Post by: holtadit on April 01, 2010, 10:43:14 am
I go first :D
Why does increasing the space between the pins in a light ray experiment improve accuracy ? Put it another way : why should there be such a large gap between each individual pin ?
Post by: Amr Fouad on April 01, 2010, 10:52:24 am
now try widening out the space..c the diff?
in other words..to avoid parallex error..
hope that helped.. :)
Post by: holtadit on April 01, 2010, 11:05:12 am
well that's simple...put ur two index fingers behind each other and try to spot smth infront of u..it's gonna be hard to spot accurately..
now try widening out the space..c the diff?
in other words..to avoid parallex error..
hope that helped.. :)
Thanks Amr. Nice analogy !
Post by: holtadit on April 01, 2010, 11:07:59 am
The examiners report also refers to the TRIANGLE METHOD alot. What is this method/how does it work.
The only way I know to calc. a gradient is using (y2-y1)/(x2-x1).
Post by: Amr Fouad on April 01, 2010, 11:11:16 am
wut the examiners do is that they use a large triangle (to increase accuracy in taking the averag).. and divide the y-side by the x-side..
so wut u should do is draw the trinagle, divide the vertical length by the horizontal one..
hope that helped again ;D
Post by: holtadit on April 01, 2010, 11:41:07 am
Whats a coherent answer ? The MS says increases the k.e. of the water (ignore heat/sound)
During Boiling of water why doesnt the temperature of the liqiuid rise ?
Post by: Adzel on April 01, 2010, 12:13:52 pm
Post by: @d!_†oX!© on April 01, 2010, 04:16:12 pm
Question 3 (b) iii)The answer refers to the concept of "latent heat of vaporization", so just read that part in your textbook to get the exact answer
Whats a coherent answer ? The MS says increases the k.e. of the water (ignore heat/sound)
During Boiling of water why doesnt the temperature of the liqiuid rise ?
Post by: °o.O-hash94-O.o° on April 01, 2010, 05:38:23 pm
I am making this thread sticky!
Post by: holtadit on April 02, 2010, 08:50:37 am
The answer refers to the concept of "latent heat of vaporization", so just read that part in your textbook to get the exact answer
It just so happens that I have a very sucky, yet expensive, textbook. :P
Stilll wanna help me ?
Post by: holtadit on April 03, 2010, 07:40:49 am
In the attached picture, would the induced e.m.f. flow in direction shown by the RED arrow if the magnet were pushed in the direction shown?
If the magnet were pulled out of the coil would the induced e.m.f. flow in the direction shown by the PINK arrow ?
ALSO in which direction does the pointer kick towards in each case and why ?
Post by: holtadit on April 03, 2010, 08:25:00 am
ONe more too: if a fuse is rated at 5A does that mean it will blow when the current is AT 5 A or when it EXCEEDS 5A ???
Post by: astarmathsandphysics on April 03, 2010, 08:56:24 am
Post by: holtadit on April 03, 2010, 09:08:04 am
I have a poor understanding of Lenz's law as its not in my textbook and probably not part of my syllabus. But I still want to understand it.
In the attached picture, would the induced e.m.f. flow in direction shown by the RED arrow if the magnet were pushed in the direction shown?
If the magnet were pulled out of the coil would the induced e.m.f. flow in the direction shown by the PINK arrow ?
ALSO in which direction does the pointer kick towards in each case and why ?
Please this question too astar.
Post by: The Golden Girl =D on April 03, 2010, 02:22:12 pm
Post by: holtadit on April 03, 2010, 02:40:54 pm
And if the magnet is pulled out of the coil the emf flows in the red arrows's direction ?
Post by: The Golden Girl =D on April 03, 2010, 02:55:23 pm
Post by: The Golden Girl =D on April 03, 2010, 02:56:09 pm
So if the magnet is pushed into the coil the emf flows in the pink arrow's direction ?
And if the magnet is pulled out of the coil the emf flows in the red arrows's direction ?
use the right hand rule of a wire and u'll get the whole thing , don't worry it's easy
Post by: holtadit on April 03, 2010, 05:00:57 pm
In diagram 2 its another circuit with an OPEN switch, voltmeter and 12V supply. NO COMPONENTS.
First question: in Diagram one would the P.D. across the wire be 0 V ? Because there should be no change in the PE of the individual charges
SECOND QUESTION: In diagram 2 would the P.D. across the OPEN switch be 12 V ?
Post by: nid404 on April 04, 2010, 06:14:34 am
In the first one, P.D across the wire would be 12V, since resistance of the wire is negligible and there is no other component....
Whenever you see a switch open, remember, no current flows, and hence, there is no P.D
Post by: Amr Fouad on April 04, 2010, 09:39:55 am
Diagrams correct....but voltage jst the opp
In the first one, P.D across the wire would be 12V, since resistance of the wire is negligible and there is no other component....
Whenever you see a switch open, remember, no current flows, and hence, there is no P.D
Hey, that is totally incorrect..
Yes it is true, in the 1st diagram, the voltage is zero. V=IR, and R=o, therefore V=0..
Again, in the second one, V=o, as I=0..
Post by: nid404 on April 04, 2010, 11:16:00 am
Post by: haris94 on April 04, 2010, 07:13:48 pm
diagram 1: 12V
diagram 2: 0V
Post by: Amr Fouad on April 04, 2010, 07:58:15 pm
ask astar.pm him if u dont believe me...
V=RI...R=0...so V=0..period.
Post by: nid404 on April 05, 2010, 07:53:41 am
I am dead sure....anyway u want to ask him...go ahead...always better to clear ur doubts
Post by: holtadit on April 05, 2010, 02:11:35 pm
Heres my next query. For a D.C. output how should I draw the waves ? The first picture (top) or second one (bottom) ?
Post by: holtadit on April 05, 2010, 03:27:19 pm
Post by: holtadit on April 05, 2010, 04:17:04 pm
Post by: Adzel on April 05, 2010, 05:47:47 pm
ans: The first picture (top)
Post by: Saladin on April 05, 2010, 06:11:31 pm
That is why, the rectified current simply looks the like original one with the bottom cut off.
Post by: haris94 on April 05, 2010, 09:17:27 pm
if the d.c output is from a bridge rectifier, the negative current is converted to positive and the output on the screen will be like diagram 2.
am i right?
Post by: Saladin on April 05, 2010, 10:03:59 pm
Post by: holtadit on April 06, 2010, 06:18:57 am
one question - applies to the same diagram above
if the d.c output is from a bridge rectifier, the negative current is converted to positive and the output on the screen will be like diagram 2.
am i right?
So your saying if a diode receives an AC input the output will be the second diagram ?
Post by: Saladin on April 06, 2010, 07:33:07 am
a diode, simply has the ability to block current, and block 100% of it.
so say u giv an alternating current.
the di-ode will block everything.
which is unlike a recitifier, which will ony block a the alternating current.
Post by: haris94 on April 06, 2010, 08:24:13 am
this means it will allow the positive current to flow and will block the negative
(an ac supply has both positive and negative current)
since the negative part is blocked, the output will be the the positive bump and the negative which is a straight line (like your first diagram)
a bridge rectifier is different. here u use 4 diodes and the negative current is converted (not blocked) to positive current
and so the output curve will be the positive bumps repeated continuously (like your second diagram)
got it ?
Post by: The Golden Girl =D on April 06, 2010, 08:25:50 pm
Okay never mind that.
Heres my next query. For a D.C. output how should I draw the waves ? The first picture (top) or second one (bottom) ?
i am srry to say that guys u r wrong ..the right one is the second one ....but as for the first one it's when a diode is used "which changes ac to dc " ;)
Post by: nid404 on April 07, 2010, 10:12:02 am
Post by: holtadit on April 16, 2010, 12:16:28 pm
Post by: Amr Fouad on April 16, 2010, 12:21:59 pm
How is the answer c ???
Thermal capacity depends on 2 things:
1. mass of object
2. Type of material
we will not use number 2 as all are made of copper..however, we will use point 1..
a tube is hollow, while a rod is not, therefore a rod is heavier, ie greater mass..
therefore, the answer should be A or C..and since C is heavier,
C is the correct answer..
got that Ari?
Post by: Amr Fouad on April 16, 2010, 12:23:19 pm
lol..so it shud be A or C :)
Post by: holtadit on April 16, 2010, 12:35:45 pm
Post by: Amr Fouad on April 16, 2010, 12:43:22 pm
Thanks again...
anytime :)
Post by: ~HyDrOgEn~ on April 18, 2010, 10:31:41 pm
Post by: Saladin on April 18, 2010, 10:35:27 pm
Post by: hmh on April 18, 2010, 10:35:46 pm
what is meant by terminal velocity? thanks!
The velocity when a falling object is no longer accerlerating; the force due to gravity is equal to the opposing force of air resistance.
Post by: ~HyDrOgEn~ on April 18, 2010, 10:40:22 pm
Post by: Amr Fouad on April 18, 2010, 10:43:21 pm
thanks another quetion , what is meant by the term efficency!
efficiency is the percentage of useful energy ouytpu.It equals:
(usefyl energy output/total energy input) x 100%
got that?
Post by: ~HyDrOgEn~ on April 18, 2010, 11:05:46 pm
Post by: holtadit on April 19, 2010, 04:47:33 pm
Consider the scenario where a layer of invar is above copper (expands more than invar).
How and why would it bend ? Any hard and fast rule to rembr this stuff ?
Post by: Saladin on April 19, 2010, 05:02:43 pm
This is because consider a circle, the outer layer will be longer than the inner layer. Similarly, because coppe expands more, it will be the outer later, and thus the bimetallic strip will bend upwards.
hope dat helps.
Post by: holtadit on April 21, 2010, 06:41:03 am
What do they mean ? Before this part I had calculated a reading of 0.003 A on an ammeter in a circuit.
Post by: nid404 on April 21, 2010, 07:19:34 am
Post by: holtadit on April 21, 2010, 09:11:54 am
Upload the paper please
hang on I have to scan it
Post by: holtadit on April 21, 2010, 09:19:02 am
Post by: nid404 on April 21, 2010, 10:03:05 am
The full scale value should be the minimum whole value which can offer good linearity and accuracy
Post by: holtadit on April 21, 2010, 10:12:18 am
Full scale deflection is the max value displayed on the ammeter...I'd suggest a full scale deflection of 0.01 A...since you measure current with power 10-3
The full scale value should be the minimum whole value which can offer good linearity and accuracy
I see, I get what you mean.
Heres another:
The pic. shows identical lamps X adn Y in series. The lamps are at normal brightness. A third lamp Z is connected in parallel to X.
What happens to the brightness of lamp y ?
Post by: Amr Fouad on April 21, 2010, 10:17:15 am
I see, I get what you mean.
Heres another:
The pic. shows identical lamps X adn Y in series. The lamps are at normal brightness. A third lamp Z is connected in parallel to X.
What happens to the brightness of lamp y ?
falls
Post by: nid404 on April 21, 2010, 10:21:06 am
Since current through the lamps X n Y decrease...current splits in a parallel circuit
Post by: holtadit on April 21, 2010, 10:21:59 am
falls
Even I said that !!!!!
My answer booklet (not the real Markscheme) says it will become BRIGHTER THAN NORMAL..... -_-
Stupid answer booklet... >:(
Post by: Amr Fouad on April 21, 2010, 10:22:26 am
Now, X and Z are connected in parallel, and BOTH are in series with Y..
Post by: Amr Fouad on April 21, 2010, 10:22:53 am
Even I said that !!!!!
My answer booklet (not the real Markscheme) says it will become BRIGHTER THAN NORMAL..... -_-
Stupid answer booklet... >:(
LOL
Post by: nid404 on April 21, 2010, 10:25:13 am
Brightness is a measure of power...At constant voltage, P=I2 R. Increase in resistance due to the addition of the 3rd lamp, cause a fall in the current
Post by: The Golden Girl =D on April 22, 2010, 12:43:51 pm
Even I said that !!!!!
My answer booklet (not the real Markscheme) says it will become BRIGHTER THAN NORMAL..... -_-
Stupid answer booklet... >:(
wait a sec, y does it increase? ...now i am confused?!!? ..can someone plz explain o.0
Post by: nid404 on April 22, 2010, 12:45:22 pm
wait a sec, y does it increase? ...now i am confused?!!? ..can someone plz explain o.0
it doesn't increase
we're explaining why it would decrease...
check our posts above...ull understand why
Post by: The Golden Girl =D on April 22, 2010, 12:47:09 pm
it doesn't increase
we're explaining why it would decrease...
check our posts above...ull understand why
thx alot :-[
Post by: nid404 on April 22, 2010, 12:48:54 pm
thx alot :-[
lol...no prob :)
Post by: saleemsamer on April 23, 2010, 11:17:55 am
Post by: astarmathsandphysics on April 23, 2010, 03:58:09 pm
Post by: holtadit on April 23, 2010, 04:01:04 pm
i have a doubt can some1 explain to me the mechanical methods of measurement of small distances it was in the 1st question of O/N 2009 i need both ways plz.
Search on youtube how to read vernier callipers. Excellent.
Post by: saleemsamer on April 23, 2010, 04:18:05 pm
http://www.youtube.com/watch?v=CdNkxw4-u-Q ( Micrometer)
http://www.youtube.com/watch?v=Vz40xmrdhyY (Vernier Caliper )
Post by: saleemsamer on April 23, 2010, 04:32:30 pm
Post by: CatAly$t on April 26, 2010, 07:12:35 pm
Post by: Cool guy on April 26, 2010, 07:24:14 pm
Post by: astarmathsandphysics on April 26, 2010, 10:20:39 pm
radioactive carbon 14 is constant ly produced in the atmosphere by caosmic rays.Plants use it to grown and animals eat the plants. a steady concentration is maintained. When the living thing dies they stop earing the plants and the carbon 14 concentration starts to fall since the carbon decays at a constant rate and is not repkaced.By measuring the concentration of carbon 14 we can say how long since the animal died.
Post by: Malak on April 29, 2010, 12:18:22 pm
Fig. 8.1 shows a long straight wire between the poles of a permanent magnet.
It is connected through a switch to a battery so that, when the switch is closed, there is a
steady current in the wire.
(wire in a direction at right angles to the page)
How can we find the direction of the movement of wire..I know by using fleming's L.H.R but there is no direction for current given?Or maybe i didnt understood the question :S
Post by: holtadit on April 29, 2010, 04:19:39 pm
2002 Nov Paper 3 Question 8:
Fig. 8.1 shows a long straight wire between the poles of a permanent magnet.
It is connected through a switch to a battery so that, when the switch is closed, there is a
steady current in the wire.
(wire in a direction at right angles to the page)
How can we find the direction of the movement of wire..I know by using fleming's L.H.R but there is no direction for current given?Or maybe i didnt understood the question :S
Read the question it says that the current flows into the page. Use Fleming Left hand rulle and it should be easy now.
Post by: Malak on April 30, 2010, 12:54:19 pm
Post by: omair on April 30, 2010, 01:23:57 pm
Post by: astarmathsandphysics on April 30, 2010, 01:36:01 pm
Post by: The Golden Girl =D on May 01, 2010, 07:05:10 am
how can we use the screw guage if there are many sheets of paper and can you explain the specific latent and specific heat capacity also how can we know which of the given objects have high heat capacity
the equation for heat capacity ...... Energy = mass * heat capacity* (temp 2 - temp1)
to find whether this material has more or less heat capacity is by using the formula as follows:
heat capacity = Energy / mass *(temp 1 - temp 2 ) ......
if it has more difference in the temperature it has low heat capacity , and vice versa.
..................................
as for the screw gauage , i never heard of it ?! so u'll have to tell me the paper that has this question so thati can help u .
...........................
specific latent heat of fusion = is the amount of heat energy given to a unit mass of a solid to change it to a liquid at a fixed temperature
specific latent heat of vaporization = is the amount of heat energy given to a unit mass of a liquid into vapor /gas at a fixed temperature
specific heat capacity = is the amount of heat energy given to a unit mass of a substance to increase temperature by 1 degree Celsius
hope i helped
Post by: sweetgirl on May 01, 2010, 08:07:47 am
Post by: holtadit on May 01, 2010, 08:14:23 am
hey any one know what are the important topics for june unit 1 and 2 :)
I dont understand. Are you talking about IGCSEs ?
Post by: Snake on May 02, 2010, 11:27:50 am
Post by: holtadit on May 02, 2010, 11:47:07 am
Can some one please explain to me how to use F.L.H.R and F.R.H.R?
(http://upload.wikimedia.org/wikipedia/commons/1/15/LeftHandOutline.png)
FLHR
Post by: The Golden Girl =D on May 02, 2010, 03:55:29 pm
um how do i revise for paper 6 and 1 phy IGCSE on the night/day before the Eaxm itself?
thx in advance
Post by: Snake on May 02, 2010, 04:00:47 pm
i got a question for everyone but i'd also like astarmaths and physics to answer me if he wishes to .
um how do i revise for paper 6 and 1 phy IGCSE on the night/day before the Eaxm itself?
thx in advance
Well my friends who have done the IGCSE told me to just do past papers for 6 and 1 with revision, however I think I'm going to just study and do a couple of pastpapers before the test and go to bed early. Hope I helped :)
Post by: The Golden Girl =D on May 02, 2010, 04:04:06 pm
Well my friends who have done the IGCSE told me to just do past papers for 6 and 1 with revision, however I think I'm going to just study and do a couple of pastpapers before the test and go to bed early. Hope I helped :)
ya i was thinkin the same thing but i still wanna get diff opinions and take the average :P ......ur the first opinion so thx :)
Post by: Cool guy on May 02, 2010, 11:30:43 pm
Post by: holtadit on May 03, 2010, 05:26:04 am
Or is it the second one ?
Post by: nid404 on May 03, 2010, 05:33:34 am
Post by: holtadit on May 03, 2010, 05:46:23 am
2nd one
I know not to doubt you, but are you sure ? :-\
Post by: nid404 on May 03, 2010, 05:50:07 am
I know not to doubt you, but are you sure ? :-\
lol...you should...nothing wrong
logically it's the 2nd one...it has to be!! lol
Post by: Snake on May 03, 2010, 08:33:58 am
Post by: haris94 on May 03, 2010, 08:34:59 am
Post by: Vin on May 04, 2010, 08:27:43 am
a permanent magnet can be demagnetized by wrapping a coil and passing alternating current
steel can be permanently magnetized by passing direct current
right>>?
also can somebody explain me the reason behind it too..i forgot :P
Post by: Ghost Of Highbury on May 04, 2010, 09:00:48 am
ALso, by placing the magnet in an alternating magnetic field which can be created by coiling it and passing an A/C current.
Passing direct current will only make it magnetized. Steel can be permanently magnetized by Stroking (Moving a magnet from one end of the item to the other repeatedly) or by Placing it in an external magnetic field.
The most common method is stroking, however there is another method which involves the magnet to be heated strongly, and allowed to be cool in a magnetic field and hammering it as it cools.
Post by: Baladya on May 04, 2010, 10:08:02 am
Demagnetize by heating the magnet strongly enuf or past the Curie Temperature.
ALso, by placing the magnet in an alternating magnetic field which can be created by coiling it and passing an A/C current.
Passing direct current will only make it magnetized. Steel can be permanently magnetized by Stroking (Moving a magnet from one end of the item to the other repeatedly) or by Placing it in an external magnetic field.
The most common method is stroking, however there is another method which involves the magnet to be heated strongly, and allowed to be cool in a magnetic field and hammering it as it cools.
Another thing, you can also place the magnet W-E and hammer it (demagnetise). Also, the heating method is the best method for demagnetising
Post by: Vin on May 04, 2010, 10:27:25 am
Post by: Ghost Of Highbury on May 04, 2010, 11:06:26 am
Post by: The Golden Girl =D on May 04, 2010, 11:30:32 am
Demagnetize by heating the magnet strongly enuf or past the Curie Temperature.for no 2 does the steel have to be moved in and out or just placed in it's place and it'll simply get demagnetized? ....... can someone plz clear my doubt in this :-\
ALso, by placing the magnet in an alternating magnetic field which can be created by coiling it and passing an A/C current.
2.Passing direct current will only make it magnetized. Steel can be permanently magnetized by Stroking (Moving a magnet from one end of the item to the other repeatedly) or by Placing it in an external magnetic field.
The most common method is stroking, however there is another method which involves the magnet to be heated strongly, and allowed to be cool in a magnetic field and hammering it as it cools.
um
Post by: Ghost Of Highbury on May 04, 2010, 11:36:04 am
Post by: The Golden Girl =D on May 04, 2010, 11:42:11 am
No need to move it, just pass an A/C current around it to demagnetize it.
thx
Post by: Ghost Of Highbury on May 04, 2010, 11:45:40 am
Post by: $H00t!N& $t@r on May 04, 2010, 01:01:33 pm
http://www.xtremepapers.net/CIE/Cambridge%20IGCSE/0625%20-%20Physics/0625_w09_qp_6.pdf (http://www.xtremepapers.net/CIE/Cambridge%20IGCSE/0625%20-%20Physics/0625_w09_qp_6.pdf)
Thanks!
Post by: Ghost Of Highbury on May 04, 2010, 01:08:07 pm
Post by: Saladin on May 04, 2010, 01:12:25 pm
Post by: Snake on May 04, 2010, 01:17:51 pm
Post by: Snake on May 04, 2010, 01:26:43 pm
Post by: holtadit on May 04, 2010, 01:26:50 pm
Please include all details including all measurements that taken.
Please go into as much detail as possible, this is to help me with the Paper 3 & 6 phy.
Also please explain how a SLIP RING commutator works.
Post by: $H00t!N& $t@r on May 04, 2010, 01:35:27 pm
The Mysterious Dude: Thanks for the diagram but you didnt include the voltmeter and the points X and Y, as asked in Q4dii (1)
Snake: I need answer fot the first part
Post by: Saladin on May 04, 2010, 01:36:15 pm
Post by: Ghost Of Highbury on May 04, 2010, 01:48:45 pm
check the image. : http://sciencecity.oupchina.com.hk/npaw/student/glossary/img/slip_rings.jpg
Post by: $H00t!N& $t@r on May 04, 2010, 02:20:42 pm
Wrong question answered, sorry.
can you please help me answer the right question? Thanks
Post by: holtadit on May 04, 2010, 03:10:25 pm
Why does the MS say the answer is the first pic ? Couldn't it also be the second pic ?
Post by: Ghost Of Highbury on May 04, 2010, 03:17:27 pm
Post by: holtadit on May 04, 2010, 03:21:00 pm
Both the images have correct answers. Could be either way.
SO would they accept either ? How sure are you ?
Post by: Ghost Of Highbury on May 04, 2010, 03:27:37 pm
A@di : try this link- http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_6.pdf)
The Mysterious Dude: Thanks for the diagram but you didnt include the voltmeter and the points X and Y, as asked in Q4dii (1)
Snake: I need answer fot the first part
Attached
Post by: Snake on May 04, 2010, 07:08:00 pm
Post by: The Golden Girl =D on May 04, 2010, 07:14:22 pm
Nov 2007 Question 4 B
paper what?
Post by: Snake on May 04, 2010, 08:52:58 pm
Post by: The Golden Girl =D on May 05, 2010, 06:04:40 am
My bad Paper 6my answer is according
to my teacher :
measure the vertical heights of the two ends of the pin and check if they r equal
to the ms:
two equal heights from bench (or other valid method)
hope i helped
Post by: Ghost Of Highbury on May 05, 2010, 06:52:18 am
SO would they accept either ? How sure are you ?
yes i am pretty sure.
Post by: Vin on May 05, 2010, 07:56:58 am
this is from 2001 paper
but i dont think this is there in the 2010 syllabus..but still wanna kno the ans..
n nothin's there in the markscheme..it says correctly drawn.. ???
Post by: ~ A.F ~ on May 05, 2010, 08:01:03 am
Post by: Vin on May 05, 2010, 08:02:31 am
Post by: Vin on May 05, 2010, 08:51:43 am
pls. excuse the drawing.. jus wanted to ask whether is it right to draw .?? this kinda ques. is in every paper..
n the ms never has ny drawings.. :)
Thanks in advance..
Post by: Snake on May 05, 2010, 09:05:14 am
Post by: holtadit on May 05, 2010, 09:08:32 am
is my answer right ?
Post by: Ghost Of Highbury on May 05, 2010, 09:17:00 am
Post by: Vin on May 05, 2010, 09:18:40 am
Which year and paper is it?
winter 2005 paper 3
Post by: holtadit on May 05, 2010, 09:26:55 am
Yes its correct. Label the lamps.
Thanks dude, please check this one too : https://studentforums.biz/index.php/topic,7291.0.html
Post by: holtadit on May 05, 2010, 09:32:48 am
hey sorry im up with another.. :)
pls. excuse the drawing.. jus wanted to ask whether is it right to draw .?? this kinda ques. is in every paper..
n the ms never has ny drawings.. :)
Thanks in advance..
There should be 3 readings taken, hence one GM tube at the top, one in the middle and one at the bottom.
This shows how the deflection would force the Beta particles up and not to the bottom, thus the lower GM tube has a lower reading than the one on the top.
Post by: Vin on May 05, 2010, 11:29:00 am
There should be 3 readings taken, hence one GM tube at the top, one in the middle and one at the bottom.
This shows how the deflection would force the Beta particles up and not to the bottom, thus the lower GM tube has a lower reading than the one on the top.
yup thts true but do v have to show tht in the drawing??..because wat u've said is supposed to answered in the following questions..
Post by: holtadit on May 05, 2010, 11:42:03 am
yup thts true but do v have to show tht in the drawing??..because wat u've said is supposed to answered in the following questions..
Draw it too. Play safe, why take any risk on an exam that will determine your future ?
Post by: Vin on May 05, 2010, 11:48:37 am
Draw it too. Play safe, why take any risk on an exam that will determine your future ?
hmmm..absolutely true..Thanks.. :)
Post by: $H00t!N& $t@r on May 05, 2010, 04:42:39 pm
Thanks
Post by: Saladin on May 05, 2010, 04:55:04 pm
The thermocouple is very sensitive and can measure temperatures from –250OC to 1500OC. It is especially useful for measuring the temperature of very small objects and rapidly changing temperatures.
(http://www.teachnet.ie/dkeenahan/images/thermocouple.jpg)
Post by: $H00t!N& $t@r on May 05, 2010, 05:57:33 pm
This is a temperature measuring device. It consists of two wires of different metals, such as copper and iron, joined together. If there is a temperature difference between the two junctions, a current flows. The current causes a deflection on a galvanometer. So, for example, if the temperature of one junction is at 0OC and the other used to measure the temperature of an object then, depending on the current that flows, it is possible to work out the temperature of the object.
The thermocouple is very sensitive and can measure temperatures from –250OC to 1500OC. It is especially useful for measuring the temperature of very small objects and rapidly changing temperatures.
(http://www.teachnet.ie/dkeenahan/images/thermocouple.jpg)
Thanks alot! you've been really helpful. I've been trying to figure out how to add rep. cz u really deserve it. Cud u tell me hw to do it. ;D Thanks again! May you have a successful future. Ameen
Post by: Saladin on May 05, 2010, 06:03:25 pm
Thanks alot! you've been really helpful. I've been trying to figure out how to add rep. cz u really deserve it. Cud u tell me hw to do it. ;D Thanks again! May you have a successful future. Ameen
Press the heart button in my post.
Post by: Vin on May 05, 2010, 07:47:31 pm
hey in the ms they say refractive index (n) = sin i / sin r ... OR sin r / sin r
so aren't they two different things??
n can some1 explain me the question too..its june 09 paper 3
Post by: ~ A.F ~ on May 05, 2010, 07:55:43 pm
if water's n= 1.5, air's n= 1/1.5
Post by: Ghost Of Highbury on May 05, 2010, 08:20:12 pm
hey in the ms they say refractive index (n) = sin i / sin r ... OR sin r / sin r
so aren't they two different things??
n can some1 explain me the question too..its june 09 paper 3
One quick tip about when to use sin r / sin i and the reverse.
Mostly, go for sin i/sin r, however, if the answer is less than 1, reverse it. Meaning, use sin r/sin i.
This is because , refractive indices are never < 1. So, whener u get the index < 1, u know that the formula u've used is incorrect.
Post by: Malak on May 05, 2010, 09:23:12 pm
One quick tip about when to use sin r / sin i and the reverse.
Mostly, go for sin i/sin r, however, if the answer is less than 1, reverse it. Meaning, use sin r/sin i.
This is because , refractive indices are never < 1. So, whener u get the index < 1, u know that the formula u've used is incorrect.
But wat if the R.I is given n we r supposed to find an Angle...Is there a way to know using which form of the equation is correct..?
Post by: haris94 on May 05, 2010, 09:33:48 pm
- if ray is going from denser to rarer, then angle of refraction will be greater than angle of incidence
- if ray is going from a rarer to a denser medium, then the angle of incidence is greater than the angle of refraction
Post by: Malak on May 05, 2010, 09:49:43 pm
Sorry, internet bad, very slow cant upload much.
Is this diagram correct for that question :S
(http://img706.imageshack.us/img706/4984/67891973.png) (http://img706.imageshack.us/i/67891973.png/)
Post by: Snake on May 05, 2010, 09:54:47 pm
Is this diagram correct for that question :S
(http://img706.imageshack.us/img706/4984/67891973.png) (http://img706.imageshack.us/i/67891973.png/)
Yes it is but remember to label the motors
Post by: The Golden Girl =D on May 06, 2010, 05:58:26 am
that this paper is very easy it;s alll abt measuring and precautions ad stuff ..the only thing u gotta do is that u should do as much past papers as u can before the exam ......
(but for me cuz i forget alot :-[ i might just make a quick revision on the heat lesson as well as the waves )
gd luck !!
Post by: Vin on May 06, 2010, 09:17:59 am
One quick tip about when to use sin r / sin i and the reverse.
Mostly, go for sin i/sin r, however, if the answer is less than 1, reverse it. Meaning, use sin r/sin i.
This is because , refractive indices are never < 1. So, whener u get the index < 1, u know that the formula u've used is incorrect.
hmmm..Thanks.. :)
Post by: Vin on May 06, 2010, 09:20:39 am
u kno last time i asked how am i supposed to study for paper 6 phy IGCSE ...... and some memebers over here answered ...well i got the answer from my tutor and here it goes :
that this paper is very easy it;s alll abt measuring and precautions ad stuff ..the only thing u gotta do is that u should do as much past papers as u can before the exam ......
(but for me cuz i forget alot :-[ i might just make a quick revision on the heat lesson as well as the waves )
gd luck !!
yup physics paper 6 is quite easy..
also they usually ask similar questions..so solvin papers as u said is really a good idea..
guess wat my first ever written paper fo igcse is phy paper 6!!! :) :)
Post by: haris94 on May 06, 2010, 09:36:26 am
good luck all!!
Post by: Malak on May 06, 2010, 10:11:13 am
if thats the case, then just keep in mind that
- if ray is going from denser to rarer, then angle of refraction will be greater than angle of incidence
- if ray is going from a rarer to a denser medium, then the angle of incidence is greater than the angle of refraction
Ohkey...Thx
And thx snake..
And Can anyone Explain me The motor effect...I cant seem to understand it :S
And wats the difference between An AC generator and a DC motor... :S
Thx
Post by: Baladya on May 06, 2010, 10:50:48 am
The motor effect i think is the thing i just told u about: when a wire has current in it, it creats a magnetic field. This magnetic field interacts with the magnet so it spins (just like u put to similar poles next to each other, they will repel and spin or smth) (this is why my dad keeps telling me not to leave electricity next to me while sleeping cuz its not healthy :P)[but m not sure of the health thing tho, cuz our teacher said that magnetic forces are okay to the body, but anyway this is just an extra thing ;D ^^]
Now my turn :D ;D
http://www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Nov/0625_w08_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Nov/0625_w08_qp_6.pdf)
Question 2. I don't want answers, i just want to understand. First, what is the motion of the current? Second, if it comes from right to left, how come the table show that ciruit 3 has the least Voltage in the Voltmeter. To me it looks like it had a longer path through wire D>C>B and then S, so its supposed to lose more voltage and the voltage difference would be more...
http://www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Nov/0625_w08_qp_03.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Nov/0625_w08_qp_03.pdf)
http://www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Nov/0625_w08_ms_3.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Nov/0625_w08_ms_3.pdf)
Also this, Question 1) d) ii) I freakin don't understand why is 0.72 wrong!! I got the speed in (i) which is 0.6 and all i have to do is multiply by 1.2. This is what the mark scheme says but they say that the answer shouldnt be 0.72 HOWWWWW??!!!
Post by: Baladya on May 06, 2010, 12:34:54 pm
The whole of a sealed, empty, dusty room is kept at a constant temperature of 15 °C. Light
shines into the room through a small outside window.
An observer points a TV camera with a magnifying lens into the room through a second
small window, set in an inside wall at right angles to the outside wall.
Dust particles in the room show up on the TV monitor screen as tiny specks of light.
(a) In the space below draw a diagram to show the motion of one of the specks of light over
a short period of time.
Post by: Malak on May 06, 2010, 02:54:30 pm
Thx alot.... :D
Question:
What is the way of making sure that when u remove electrodes from a beaker the gap between the electrodes remain same?Or anyother way of measuring the gap between the electrodes while they are immersed :S
And can anyone clearly explain what is the Parallax error and how to avoid it?
Thx...
Post by: Helium on May 06, 2010, 06:07:16 pm
When calculating the gradient of a line in PAPER 6 a mark is given for drawing a triangle 'more than half the length of the line'.
The examiners report also refers to the TRIANGLE METHOD alot. What is this method/how does it work.
The only way I know to calc. a gradient is using (y2-y1)/(x2-x1).
Well there are 2 ways to calculate the gradient.
1. By taking 2 points on the line and using (y2-y1)/(x2-x1) like you said.
2. Is by using the triangle method you take the 2 points you connect them by a tringle , By forming a traingle you calculate the differece
in y and divide by difference in x. The direction of the line will tell if the value will be positive or negative.
hope u understsand,
use this link
http://www.mathsteacher.com.au/year10/ch03_linear_graphs/02_gradient/line.htm
Its quite simple if you get used to it, and its much quicker than using th formula.
Post by: Ghost Of Highbury on May 06, 2010, 06:41:22 pm
An ac generator generates electricity by the electromagnetic induction. So basically u have only a magnet, wire, and an ammeter. Cut the field lines with the wire and u will see electricity being generated (the ammeter have a reading). On the other hand, a d.c motor works by electricity not make it. Again u have a magnet,coil around like a piece of wood or smth, split ring and brushes to allow it it to spin freely, and a POWER SUPPLY. This is the main diff, the power supply supllies the wire with electricity, when there is eletricity inside a wire, it creates a magnetic field. This magnetic fields interacts with the magnetic field of the magnet and causes the piece of wood to spin. The spinning motion cause other things to spin (for example wheals in toy cars). Also this is by d.c like the name say, while the a.c generator generates an a.c current ;) Hope this helps :)
The motor effect i think is the thing i just told u about: when a wire has current in it, it creats a magnetic field. This magnetic field interacts with the magnet so it spins (just like u put to similar poles next to each other, they will repel and spin or smth) (this is why my dad keeps telling me not to leave electricity next to me while sleeping cuz its not healthy :P)[but m not sure of the health thing tho, cuz our teacher said that magnetic forces are okay to the body, but anyway this is just an extra thing ;D ^^]
Now my turn :D ;D
http://www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Nov/0625_w08_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Nov/0625_w08_qp_6.pdf)
Question 2. I don't want answers, i just want to understand. First, what is the motion of the current? Second, if it comes from right to left, how come the table show that ciruit 3 has the least Voltage in the Voltmeter. To me it looks like it had a longer path through wire D>C>B and then S, so its supposed to lose more voltage and the voltage difference would be more...
http://www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Nov/0625_w08_qp_03.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Nov/0625_w08_qp_03.pdf)
http://www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Nov/0625_w08_ms_3.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Nov/0625_w08_ms_3.pdf)
Also this, Question 1) d) ii) I freakin don't understand why is 0.72 wrong!! I got the speed in (i) which is 0.6 and all i have to do is multiply by 1.2. This is what the mark scheme says but they say that the answer shouldnt be 0.72 HOWWWWW??!!!
Im myself confused about the circuit thing, sry can't help in that.
However the other one.
U cannot use the formula speed - distance/time for an object which is accelerating
Use the formula s = 0.5at2
s = 0.5*0.5*1.22 = 0.25 * 1.2 * 1.2 = 0.36m
and about the dust particle, yes its correct, but just make a dot for a particle. Something like the attached one.
Post by: Ghost Of Highbury on May 06, 2010, 06:49:03 pm
Quote
Thx alot....
Question:
What is the way of making sure that when u remove electrodes from a beaker the gap between the electrodes remain same?Or anyother way of measuring the gap between the electrodes while they are immersed :S
And can anyone clearly explain what is the Parallax error and how to avoid it?
Thx...
No clue about the electrodes thing. it was left unanswered here too : https://studentforums.biz/index.php/topic,1057.msg8998.html#msg8998
Parallax Error : Error in reading an instrument employing a scale and pointer because the observer's eye and pointer are not in a line perpendicular to the plane of the scale.
Avoid parallax error : Placing the eye perpendicular to the marking on the scale to be read. If you are measuring the volume of liquid in a measuring cylinder , make sure you positioned your eye to take readings at the bottom of menicus for water and top of menicus for mercury.
Post by: Baladya on May 06, 2010, 06:52:23 pm
Im myself confused about the circuit thing, sry can't help in that.
However the other one.
U cannot use the formula speed - distance/time for an object which is accelerating
Use the formula s = 0.5at2
s = 0.5*0.5*1.22 = 0.25 * 1.2 * 1.2 = 0.36m
and about the dust particle, yes its correct, but just make a dot for a particle. Something like the attached one.
WOW. 5 days for the exam and i still don't know this rule... Thanks school :-X And Thanks Aodi :D ;D :P
Post by: Ghost Of Highbury on May 06, 2010, 07:00:35 pm
WOW. 5 days for the exam and i still don't know this rule... Thanks school :-X And Thanks Aodi :D ;D :P
Your Welcome.
Post by: Snake on May 06, 2010, 07:04:35 pm
With V being Final speed and U initial speed and T time
Post by: Saladin on May 06, 2010, 07:06:53 pm
I thought the formula to find acceleration was A=V-U/T
With V being Final speed and U initial speed and T time
That is correct.
Post by: Malak on May 06, 2010, 09:03:12 pm
No clue about the electrodes thing. it was left unanswered here too : https://studentforums.biz/index.php/topic,1057.msg8998.html#msg8998
Parallax Error : Error in reading an instrument employing a scale and pointer because the observer's eye and pointer are not in a line perpendicular to the plane of the scale.
Avoid parallax error : Placing the eye perpendicular to the marking on the scale to be read. If you are measuring the volume of liquid in a measuring cylinder , make sure you positioned your eye to take readings at the bottom of menicus for water and top of menicus for mercury.
Thx alot :)
Another question :
When u wrap the string aroung something and measure that length...How do u find the circumference...
Do you multiply the length by the number of times the string is wrapped or u divide it by that number?
Post by: Hesham Mhd on May 06, 2010, 09:48:43 pm
Post by: Hesham Mhd on May 06, 2010, 09:51:14 pm
If a ray diagram is given, what should be done? i mean, when should we magnify and when should we simply draw the upside-down image? Thanks
Post by: Ghost Of Highbury on May 06, 2010, 09:57:44 pm
Post by: winnie101 on May 06, 2010, 09:58:37 pm
Thanks
Post by: Snake on May 07, 2010, 12:00:26 am
could someone plz explain to me ques. 5,7,15,18,20,and 29 form m/j 2009 paper 1 physics cie AS level
Thanks
Wrong place to post I think. Post your question again here https://studentforums.biz/index.php/board,82.0.html
Post by: Snake on May 07, 2010, 12:02:02 am
That is correct.
So why do they use 0.5AT^2? maybe he confused it with 0.5MV^2 (For Kinetic Energy)?
Woo Now I'm confused :S
Post by: nid404 on May 07, 2010, 06:34:20 am
So why do they use 0.5AT^2? maybe he confused it with 0.5MV^2 (For Kinetic Energy)?
Woo Now I'm confused :S
huh?
distance is given by ut+1/2at2
k.e= 1/2 mv2
Post by: nid404 on May 07, 2010, 09:02:31 am
Can any1 plz explain the thermal expansion? And What expands more.. solids, liquids or gases and why? Thanks in advance
Thermal expansion is a lot in itself.
http://www.docbrown.info/page03/3_52states.htm excellent stuff.
Post by: Hesham Mhd on May 07, 2010, 09:14:52 am
Post by: nid404 on May 07, 2010, 09:17:36 am
solids<liquids<gases
What else do you want to know..?
if you put pointers from the syllabus, it'll be easier for me
Post by: Hesham Mhd on May 07, 2010, 09:22:57 am
Post by: nid404 on May 07, 2010, 09:25:19 am
Post by: holtadit on May 07, 2010, 09:27:21 am
um ok, 'Describe Qualitatively the thermal expansion in solids, liquids and gases' ?
In short:
solids have strong electrostatic bonds between particles that prevent them from expanding too much.
liquids have slightly weaker bonds and can expand a bit more
gases have NO forces of attraction and can expand to fill up container and exert GREATER pressure when heated.
Post by: Hesham Mhd on May 07, 2010, 10:29:02 am
Post by: holtadit on May 07, 2010, 10:32:02 am
Thanks alot dude, and, can yu explain the thermal expansion in terms of molecules?
As the temperature rises the kinetic energy of the molecules increases as they begin to vibrate faster. Some of this energy is used to increase the spacing between individual molecules leading to expansion of material.
Post by: Hesham Mhd on May 07, 2010, 10:44:05 am
And, if we have a converging lens, when will it form a magnified, virtual image? and when will it form a real, upside-down image?
Post by: holtadit on May 07, 2010, 11:19:11 am
real, upside down = every other position except the one above.
Post by: Hesham Mhd on May 07, 2010, 11:45:53 am
Post by: Baladya on May 07, 2010, 01:45:42 pm
Can any1 plz explain the thermal expansion? And What expands more.. solids, liquids or gases and why? Thanks in advance
http://www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Jun/0625_s08_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Jun/0625_s08_qp_6.pdf)
Can somebody draw me the rays path plz...
I dont understand their stupid instructions :-X
Post by: Vin on May 07, 2010, 02:46:12 pm
http://www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Jun/0625_s08_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Jun/0625_s08_qp_6.pdf)
Can somebody draw me the rays path plz...
I dont understand their stupid instructions :-X
working on it.. :) :)
Post by: Vin on May 07, 2010, 03:07:04 pm
working on it.. :) :)
Post by: Malak on May 07, 2010, 03:53:06 pm
http://www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Nov/0625_w08_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Nov/0625_w08_qp_6.pdf)
Thx
Post by: Vin on May 07, 2010, 03:58:18 pm
Can anyone Answer 08 Nov P6 Q2 all parts...
http://www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Nov/0625_w08_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Nov/0625_w08_qp_6.pdf)
Thx
yup gimme some time..
i'll try my best.. :)
Post by: Vin on May 07, 2010, 04:22:04 pm
yup gimme some time..sorry for the delay!! :(
i'll try my best.. :)
note the symbol of resistance wires [moderators pls. check the symbol]
c) i) 1. NO the value is not close in the experiment
2.YES, value is approx. half..
ii) Resistance of battery(supply) or at connections.. strictly not wires!!! thts wat i had written in mock test prolly a month ago..:P
Post by: holtadit on May 07, 2010, 04:24:26 pm
sorry for the delay!! :(
note the symbol of resistance wires [moderators pls. check the symbol]
c) i) 1. NO the value is not close in the experiment
2.YES, value is approx. half..
ii) Resistance of battery(supply) or at connections.. strictly not wires!!! thts wat i had written in mock test prolly a month ago..:P
The resistance wires should be substituted for the symbol for a resistor. READ THE QUESTION!
Post by: Vin on May 07, 2010, 04:26:38 pm
The resistance wires should be substituted for the symbol for a resistor. READ THE QUESTION!
OOOPPPSS!! my bad!!! really sorry i'll update the image... :)
Thanks..
really sorry!! :-[
Post by: Vin on May 07, 2010, 04:31:30 pm
sorry for the delay!! :(
note the symbol of resistance wires [moderators pls. check the symbol]
c) i) 1. NO the value is not close in the experiment
2.YES, value is approx. half..
ii) Resistance of battery(supply) or at connections.. strictly not wires!!! thts wat i had written in mock test prolly a month ago..:P
I have to stop being sooo careless!!
this is were i always tend to loose out marks!!
Post by: holtadit on May 07, 2010, 04:44:45 pm
OOOPPPSS!! my bad!!! really sorry i'll update the image... :)
Thanks..
really sorry!! :-[
I have similar problems. I am good but keeping making silly errors. BUT PRACTICE MAKES PERFECT !!
Post by: Malak on May 07, 2010, 04:53:57 pm
umm...Sorry but another question...
06 Nov P6 Q5 Part e
http://www.freeexampapers.us/IGCSE/Physics/CIE/2006%20Nov/0625_w06_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2006%20Nov/0625_w06_qp_6.pdf)
Is it A or B and why...?
Thnkyew all for helping :)
Post by: Ghost Of Highbury on May 07, 2010, 04:59:43 pm
As u see, in A, there are more coils compared to B. thus as the length of the wire has increased, the resistance has increased too.
Post by: Vin on May 07, 2010, 05:23:25 pm
I have similar problems. I am good but keeping making silly errors. BUT PRACTICE MAKES PERFECT !!
Absolutely.. thts the reason i've been solving hell lot of papers this week!! X(
Post by: holtadit on May 07, 2010, 05:30:41 pm
Absolutely.. thts the reason i've been solving hell lot of papers this week!! X(
A famous person once said: 'My dear chap, IGCSEs are all about past papers.' ;)
Post by: Vin on May 07, 2010, 05:39:36 pm
A famous person once said: 'My dear chap, IGCSEs are all about past papers.' ;)
:D I suppose its one of u moderators...:)(or even u..:P)...lol
Post by: $H00t!N& $t@r on May 07, 2010, 07:04:55 pm
Calculate the value of the specific latent heat of vaporisation obtained from this experiment. Show your working.
Post by: Vin on May 07, 2010, 07:17:22 pm
A laboratory determination of the specific latent heat of vaporisation of water uses a 120W heater to keep water boiling at its boiling point. Water is turned into steam at the rate of 0.050 g/s.
Calculate the value of the specific latent heat of vaporisation obtained from this experiment. Show your working.
P= 120 W
Heat (Q) = 120 J/s
mass = 0.05 g/s
Q = mL
L= 120/0.05
= 2400 J/g
this should be right..:)
Post by: $H00t!N& $t@r on May 07, 2010, 07:37:12 pm
P= 120 W
Heat (Q) = 120 J/s
mass = 0.05 g/s
Q = mL
L= 120/0.05
= 2400 J/g
this should be right..:)
Thanks this is the answer in d ms. the thing I was confuse with is when they said: Water is turned into steam at a rate of 0.050 g/s. I thought they meant speed. So I ws wondering how to calculate that. But hw is 0.050 g/s the mass?
Post by: Snake on May 07, 2010, 07:50:47 pm
Post by: Vin on May 07, 2010, 07:52:18 pm
but did u get the concept ??
/ sec cancels out in the equation .. ;)
Post by: Vin on May 07, 2010, 07:56:19 pm
Guys what was the transformer formula? Np/Ns=Vp/Vs=Ip/Is?
Vs/Vp = Ns/Np
to find the number of turns or voltage .. depending on ques ..
Is/Ip = Vp/Vs
to find any one if other three are given ..
also theres another formula ..
Power (loss) = I2R
Post by: $H00t!N& $t@r on May 07, 2010, 09:29:44 pm
see the thing here is, as u said they hav given the "mass" as 0.05g per second .. here i didnt literally mean it as 'mass' .. it was jus for ur understanding u kno..:)
but did u get the concept ??
/ sec cancels out in the equation .. ;)
ooooohhhhhh i see what you mean. Thanks! ;D ;)
Post by: Baladya on May 07, 2010, 10:11:30 pm
Just like i thought :)
Thanks man ;)
Post by: Malak on May 07, 2010, 10:21:03 pm
06 Nov P6 (Q1 Part c) , (Q3 Part b) http://www.freeexampapers.us/IGCSE/Physics/CIE/2006%20Nov/0625_w06_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2006%20Nov/0625_w06_qp_6.pdf)
03 Nov P6 Q1 Part d http://www.freeexampapers.us/IGCSE/Physics/CIE/2003%20Nov/0625_w03_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2003%20Nov/0625_w03_qp_6.pdf)
Thx
Post by: Vin on May 07, 2010, 11:07:19 pm
06 Nov P6 1. c) 7.5 (this one is just estimation .. theres no hard and fast rule or ny formula to determine the answer .. ur answer should obiv. a little less than b) ii)
3. b) i) is attached ..
ii) should be base as less room for any error because safer to take as the pins might be of different sizes or not placed vertically/straight.
03 Nov P6 1 d) for this i had to take help from markscheme because i dont hav a hardcopy ..
same estimation part .. V= 32.41 take say 1.41 cm3 as 'missing' part
subtract it from V to get ii)
Post by: $H00t!N& $t@r on May 08, 2010, 05:55:51 am
Q4 a
I know its a kiddy question but for some reason i dont understand what scale to use for the x-axis. If I use 0.5 a/(m/s^2) = 2 units it gets hard to plot the points
Post by: Ghost Of Highbury on May 08, 2010, 06:30:17 am
x-axis : 5 units = 0.25
Post by: $H00t!N& $t@r on May 08, 2010, 06:48:21 am
y-axis : 5 units = 0.25
x-axis : 5 units = 0.25
Thanks :)
Post by: Vin on May 08, 2010, 07:17:20 am
comon more doubts .. bring it on .. im waiting :) .. tired of studyin now .. :) :)
Post by: $H00t!N& $t@r on May 08, 2010, 09:00:10 am
http://www.freeexampapers.us/IGCSE/Physics/CIE/2005%20Nov/0625_w05_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2005%20Nov/0625_w05_qp_6.pdf)
question 2a. I always get confused with such questions!! >:(
Post by: Vin on May 08, 2010, 09:10:43 am
Sorry, I have another question...
http://www.freeexampapers.us/IGCSE/Physics/CIE/2005%20Nov/0625_w05_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2005%20Nov/0625_w05_qp_6.pdf)
question 2a. I always get confused with such questions!! >:(
gimme 2 mins .. :)
Post by: Vin on May 08, 2010, 09:28:11 am
HELPP!! I cant decide whether to put three resistors or jus one .. the ms confuses me .. :@
MODERATORS pls. check ..
Post by: nid404 on May 08, 2010, 09:32:56 am
Chem and bio are my better subjects ::) :P
Post by: Malak on May 08, 2010, 11:41:05 am
HELPP!! I cant decide whether to put three resistors or jus one .. the ms confuses me .. :@
MODERATORS pls. check ..
Umm...M not sure..But my teacher told me that the 3 resistors will be in series..M confused now
Question: 02 Jun P3 Q10 http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_3.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_3.pdf)
Can anyone explain the answer aswell
And Q4. Part B iihttp://www.freeexampapers.us/IGCSE/Physics/CIE/2003%20Jun/0625_s03_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2003%20Jun/0625_s03_qp_6.pdf)
Post by: The Golden Girl =D on May 08, 2010, 01:15:42 pm
Umm...M not sure..But my teacher told me that the 3 resistors will be in series..M confused now
Question: 02 Jun P3 Q10 http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_3.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_3.pdf)
Can anyone explain the answer aswell
Question: 03 Jun P6 Q2 part B-ii http://www.freeexampapers.us/IGCSE/Physics/CIE/2003%20Jun/0625_s03_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2003%20Jun/0625_s03_qp_6.pdf)
Which direction the normal is supposed to be :S?
i can only help u with the second one cuz right now i am extremely busy :(....
okay as for the normal line my teacher said use one set square ... place the bottom of it on the surface where it is EXACTLY PERPENDICULAR to the surface and the draw the line ...
a tip from me :P ....after u do this use a protractor and measure the angle from the normal line udrew to the surface ...if it's exactly 90 then ur drawing is 100 % correct ..but if it's not it means u gotta draw it agian until u get it right .
hope i helped
Post by: $H00t!N& $t@r on May 08, 2010, 01:19:00 pm
HELPP!! I cant decide whether to put three resistors or jus one .. the ms confuses me .. :@
MODERATORS pls. check ..
so.... is this the right answer?
Post by: The Golden Girl =D on May 08, 2010, 01:21:38 pm
so.... is this the right answer?
my teacher didn't draw line AD that way but he a bit stretched it out ..in other words, he drew a line from point A and went around the voltmeter till he reached point D...
i hope i helped
Post by: The Golden Girl =D on May 08, 2010, 01:31:18 pm
thx in advacne :D
Post by: Malak on May 08, 2010, 01:49:17 pm
i can only help u with the second one cuz right now i am extremely busy :(....
okay as for the normal line my teacher said use one set square ... place the bottom of it on the surface where it is EXACTLY PERPENDICULAR to the surface and the draw the line ...
a tip from me :P ....after u do this use a protractor and measure the angle from the normal line udrew to the surface ...if it's exactly 90 then ur drawing is 100 % correct ..but if it's not it means u gotta draw it agian until u get it right .
hope i helped
Thx :)
vv Thx..
Post by: $H00t!N& $t@r on May 08, 2010, 02:17:09 pm
Umm...M not sure..But my teacher told me that the 3 resistors will be in series..M confused nowHey for the 2nd one check this out: http://www.cambridgestudents.org.uk/subjectpages/physics/igscephysics/physicsmodelanswers/0625_s03_qp_6%20model%20answers%20final.pdf (http://www.cambridgestudents.org.uk/subjectpages/physics/igscephysics/physicsmodelanswers/0625_s03_qp_6%20model%20answers%20final.pdf)
Question: 02 Jun P3 Q10 http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_3.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_3.pdf)
Can anyone explain the answer aswell
Question: 03 Jun P6 Q2 part B-ii Which direction the normal is supposed to be :S?
And Q4. Part B iihttp://www.freeexampapers.us/IGCSE/Physics/CIE/2003%20Jun/0625_s03_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2003%20Jun/0625_s03_qp_6.pdf)
hope this helps! ;)
Post by: Fastal on May 08, 2010, 02:27:55 pm
Post by: $H00t!N& $t@r on May 08, 2010, 02:36:50 pm
woah i dint know such a site existedNow you do! ;)
Post by: Fastal on May 08, 2010, 02:51:28 pm
i think it looks like the picture attached
mark schem is right
(forgot to draw switch)
Post by: Vin on May 08, 2010, 02:57:13 pm
Umm...M not sure..But my teacher told me that the 3 resistors will be in series..M confused now
Question: 02 Jun P3 Q10 http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_3.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_3.pdf)
Can anyone explain the answer aswellQuestion: 03 Jun P6 Q2 part B-ii Which direction the normal is supposed to be :S?
And Q4. Part B iihttp://www.freeexampapers.us/IGCSE/Physics/CIE/2003%20Jun/0625_s03_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2003%20Jun/0625_s03_qp_6.pdf)
The resistors are in series if u closely ..
02 Jun P3 Q10
do you want the sub parts also.. ??
Post by: Malak on May 08, 2010, 03:18:11 pm
Yeah the sub parts too....
The resistors are in series if u closely ..
02 Jun P3 Q10
do you want the sub parts also.. ??
Thx alot
Post by: $H00t!N& $t@r on May 08, 2010, 03:20:24 pm
for that question
i think it looks like the picture attached
mark schem is right
(forgot to draw switch)
Guys! now m relly confused :( im getting different answers. what is the right answer ???
Post by: Vin on May 08, 2010, 03:29:37 pm
Yeah the sub parts too....
Thx alot
ok part b) Take reading without paper in between .. Take reading with paper in between .. subtract the two to give an estimate amount of alpha particles being released .. u might no the reason to choose paper .. its a good absorber for alpha ..
c) 1. use tongs/forceps to handle the radioactive material to keep some distance ..
2. use protective clothing gloves/coat etc.
Post by: Vin on May 08, 2010, 03:31:57 pm
can someone plz explain to me paper 6 novemeber 2005 question 1) C)
thx in advacne :D
tried my best to keep it simplified .. u may draw details ..
Post by: The Golden Girl =D on May 08, 2010, 04:29:51 pm
Thx :)
vv Thx..
np probs ::)
Post by: The Golden Girl =D on May 08, 2010, 04:32:23 pm
thx in advance
Post by: Fastal on May 08, 2010, 04:38:21 pm
Guys! now m relly confused :( im getting different answers. what is the right answer ???
what i drew and what ~VIN1094~ said
are correct, i think
Post by: Snake on May 08, 2010, 04:44:26 pm
can anyone plz explain to me November 2002 question 5)a(ii) and b) paper 6
thx in advance
5A)II) The Triangle Sizes were 1.5 (Height) and 2 (Base) both CM. Just draw the same picture only magnified by x2. So Height will be 3CM and Base will be 4CM.
B)Using a set square to make sure the ruler is horizontaly straight (the ruler) and measurer the Distance.
Post by: The Golden Girl =D on May 08, 2010, 04:50:47 pm
5A)II) The Triangle Sizes were 1.5 (Height) and 2 (Base) both CM. Just draw the same picture only magnified by x2. So Height will be 3CM and Base will be 4CM.
B)Using a set square to make sure the ruler is horizontaly straight (the ruler) and measurer the Distance.
thx :D
Post by: The Golden Girl =D on May 08, 2010, 05:00:08 pm
can anyone plz explain to me November 2002 question 5)a(ii) and b) paper 6
can someone show me a drawin of it so that i understand it perfectly?
thx in advance
Post by: Malak on May 08, 2010, 05:27:39 pm
09 Jun Q5 Part a & b http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Jun/0625_s09_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Jun/0625_s09_qp_6.pdf)
09 Nov Q5 Part a http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_6.pdf)
Thx in advance
Post by: The Golden Girl =D on May 08, 2010, 05:34:29 pm
05 Jun P6 Q4 Part d - can anyone explain the answer? http://www.freeexampapers.us/IGCSE/Physics/CIE/2005%20Jun/0625_s05_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2005%20Jun/0625_s05_qp_6.pdf)
09 Jun Q5 Part a & b http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Jun/0625_s09_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Jun/0625_s09_qp_6.pdf)
09 Nov Q5 Part a http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_6.pdf)
Thx in advance
i can help u with the first one;
umm the answer is as follows :
take the time of ex: 50 oscillations and the divide the time by 50.
hope i helped
Post by: Ghost Of Highbury on May 08, 2010, 05:40:29 pm
5a) check the the 8th post : https://studentforums.biz/index.php/topic,4578.msg139947.html#msg139947
5b) with a pen/marker, mark the ends of the diameter of the circle on the ruler, remove the cylinder, find the center of the diameter and get the reading.
nov 09 - 5a) attached.
Post by: Malak on May 08, 2010, 05:45:02 pm
Question 4 was easy...Silly me..i didnt understood
Is this diagram correct?M confused with the Ammeter and variable resistor position
http://img171.imageshack.us/img171/3774/28119081.png (http://img171.imageshack.us/img171/3774/28119081.png)
N thx
Post by: The Golden Girl =D on May 08, 2010, 05:48:35 pm
Thx Both...
Question 4 was easy...Silly me..i didnt understood
Is this diagram correct?M confused with the Ammeter and variable resistor position
(http://img171.imageshack.us/img171/3774/28119081.png)
N thx
yup it is ..
u gotta kno that the ammeter is put in series ..like how u put it .....as for the voltmeter it's out in parallel like what u did .........
got it ?
anytime :D
hope i helped ...
Post by: Ghost Of Highbury on May 08, 2010, 05:49:58 pm
Thx Both...
Question 4 was easy...Silly me..i didnt understood
Is this diagram correct?M confused with the Ammeter and variable resistor position
http://img171.imageshack.us/img171/3774/28119081.png (http://img171.imageshack.us/img171/3774/28119081.png)
N thx
Correct.
By the way, check the lens rule screen drawing in my previous post. also the link.
Post by: Snake on May 08, 2010, 05:58:09 pm
yup it is ..Does it matter if the ammeter was where the Vressistor is and the Vressistor where the ammeter was?
u gotta kno that the ammeter is put in series ..like how u put it .....as for the voltmeter it's out in parallel like what u did .........
got it ?
anytime :D
hope i helped ...
Post by: The Golden Girl =D on May 08, 2010, 06:00:01 pm
Does it matter if the ammeter was where the Vressistor is and the Vressistor where the ammeter was?
in this circuit , it's doesn't matter
Post by: Snake on May 08, 2010, 06:52:07 pm
in this circuit , it's doesn't matter
Ah ok, then I was right lol
Post by: idrees on May 08, 2010, 09:16:53 pm
what the hell is a potentiometer!
i mean how does it work .. how does it divide the voltage using resistors . yeh? atleas thats what i think :S
Post by: Vin on May 08, 2010, 09:24:10 pm
Variable resistors when used in electronics are called potentiometers .. :)
Post by: idrees on May 08, 2010, 09:41:27 pm
Variable resistors when used in electronics are called potentiometers .. :)
yeah .. how does it work?
Post by: Vin on May 08, 2010, 09:47:54 pm
well like a normal resistor .. but u can increase/decrease resistance without changing the resistor .. u use a variable resistor for ur fan regulator n stuff .. or dim lights in the living room (at least my living room :) )
they can either be used as a rheostat or potential divider
Post by: the_grim_reaper on May 09, 2010, 12:31:30 am
http://www.freeexampapers.us/IGCSE/Physics/CIE/2005%20Nov/0625_w05_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2005%20Nov/0625_w05_qp_6.pdf)
Post by: Ghost Of Highbury on May 09, 2010, 05:21:50 am
Post by: thenewkid™ on May 09, 2010, 10:46:24 am
May/June 2008 p6 q2 b(i)
Thanks alot
Post by: Fastal on May 09, 2010, 10:54:58 am
Can some1 pls help me with this:
May/June 2008 p6 q2 b(i)
Thanks alot
here:)
Post by: nid404 on May 09, 2010, 10:57:19 am
Post by: Vin on May 09, 2010, 10:59:25 am
ya i kno but u get it once u click it..
Post by: nid404 on May 09, 2010, 11:01:01 am
Post by: thenewkid™ on May 09, 2010, 11:02:39 am
Post by: thenewkid™ on May 09, 2010, 11:06:26 am
Thanks
i love freekicks
Post by: Vin on May 09, 2010, 11:07:34 am
sure nytime .. luv ur trade mark .. :)
Post by: Vin on May 09, 2010, 11:09:25 am
another1 m/j 08 p6 q 1b
Thanksi love freekicks
ya i've solved this one .. gimme some time gotta hav my lunch .. i''l be bak in a tick .. :)
Post by: thenewkid™ on May 09, 2010, 11:11:33 am
Quote
here:)I wanted may june 2008 quest 2 b (i)
Post by: Ghost Of Highbury on May 09, 2010, 11:13:54 am
another1 m/j 08 p6 q 1b
Thanksi love freekicks
Stick/Attach a pin to the 10.cm mark. place the center of the cylinder exactly on the pin. remove the pin
Post by: Fastal on May 09, 2010, 11:18:07 am
here:)
oops i did the wrong question(4b)
2b(i)
yes you can write that the numbers are close enough, only 0.03 ohm difference between doubled resistance of circuit 1 and circuit 2.
2(b)(ii)
-repeats
-switch circuit off between readings.
1(b)
Find center using 2 blocks on the sideslike this --->
|()|
then extend it so that the diameter is seen, put half of the cylinder to make sure the marks match and than push it farther in.(you can draw a diagram for all of this)
Post by: thenewkid™ on May 09, 2010, 11:27:32 am
Ilv 2 take freekicks
Post by: Fastal on May 09, 2010, 11:31:08 am
Can please tell me the justification for 2 b (i)values are close enough, only 0.03 ohm difference between doubled resistance of circuit 1 and circuit 2.Ilv 2 take freekicks
Post by: thenewkid™ on May 09, 2010, 11:32:14 am
mj 2006 p6 q 1d
Post by: The Golden Girl =D on May 09, 2010, 11:32:24 am
in other words , it is included in the syllabus ?
Post by: Fastal on May 09, 2010, 11:36:45 am
Thanks 4 ans my questions
mj 2006 p6 q 1d
5.8*6*0.2=6.96 cm3
Post by: Vin on May 09, 2010, 11:38:06 am
Stick/Attach a pin to the 10.cm mark. place the center of the cylinder exactly on the pin. remove the pin
can we use a marker pen ?? to mark the centre of the cylinder (using a scale) ..
Post by: thenewkid™ on May 09, 2010, 11:39:34 am
Post by: Ghost Of Highbury on May 09, 2010, 11:40:04 am
vol = 6 * 5.8 * 0.25 = 8.7cm^3
@golden girl - yes its very important
@Vin- Yes u can, with a pin, u find the 10cm mark. mark the center of the cylinder and put it on the pin.
Post by: The Golden Girl =D on May 09, 2010, 11:40:37 am
umm By the way do we have to kno what a micrometer screw guage means? ....cuz i saw it mentioned in jun 2003 paper 6 .....
in other words , it is included in the syllabus ?
!!!!!!!!!!!!!!!!!!!!!!!!!!!?!?!!?!?!?!??! :-\
Post by: Vin on May 09, 2010, 11:42:58 am
!!!!!!!!!!!!!!!!!!!!!!!!!!!?!?!!?!?!?!??! :-\
ya its important .. i never found it in the syllabus tho .. but my teacher told both Vernier Calipers and Screw Gauge are important .. :(
Post by: Fastal on May 09, 2010, 11:48:09 am
-use and describe the use of a mechanical method for the measurement of a small distance
Post by: Vin on May 09, 2010, 11:52:36 am
i think its the use of a scale !!
Post by: Fastal on May 09, 2010, 11:56:35 am
i think its the use of a scale !!
yeah but it says small, that could mean vernier calliper too
Post by: dodi23 on May 09, 2010, 11:57:50 am
Post by: djwaqar* on May 09, 2010, 12:01:34 pm
i actually want to know the chapters which come in P6 of physics and how many questions come from one chapter...
like from moments it comes one question but the rest i dunt get it ???
Post by: Vin on May 09, 2010, 12:02:19 pm
Post by: Vin on May 09, 2010, 12:04:04 pm
yeah one question guyz....
i actually want to know the chapters which come in P6 of physics and how many questions come from one chapter...
like from moments it comes one question but the rest i dunt get it ???
nothing specific !! u should kno everythin .. light experiments .. heat .. electricity .. moments .. springs(extension) .. etc ..
solve hell lot of papers .. ;)
Post by: djwaqar* on May 09, 2010, 12:20:31 pm
Post by: the_grim_reaper on May 09, 2010, 12:45:19 pm
Post by: Malak on May 09, 2010, 01:03:18 pm
values are close enough, only 0.03 ohm difference between doubled resistance of circuit 1 and circuit 2.Um..can u explain..How is the difference 0.03?
Post by: Vin on May 09, 2010, 01:03:31 pm
I know they aren't the best pictures around there but they might help those looking for info on micrometers and vernier callipers...
good .. had to use a magnifying glass tho :P .. nyway wat book is it ?? .. :)
Post by: Vin on May 09, 2010, 01:07:53 pm
Um..can u explain..How is the difference 0.03?
what ques is it?? which paper ?? i might b abl to help ..
Post by: Malak on May 09, 2010, 01:09:01 pm
what ques is it?? which paper ?? i might b abl to help ..
08 Jun P6 Q2 b
thx
Post by: the_grim_reaper on May 09, 2010, 01:13:09 pm
Quote
nyway wat book is it ??
Not really sure. A friend of mine mailed the photos to me. He said something like "Federal Physics." Never heard of it from anyone before.....
Post by: Ghost Of Highbury on May 09, 2010, 01:15:44 pm
Um..can u explain..How is the difference 0.03?
find their respective resistance..and find the difference, it will be = 0.03 ohms.
Post by: Vin on May 09, 2010, 01:19:07 pm
08 Jun P6 Q2 b
thx
oohk .. i hav a different method .. might get complicated but fairly accurate ..
first of all the resistors are all the same .. so v can assume a specific resistance for each one .. say 2 ohm ..
For circuit 1 ==> total resistance ..
1/2 + 1/2 + 1/2 = 3/2
so = 2/3 = 0.667 ohm..
For Circuit 2 ==> total res. ..
1/4 + 1/2 = 3/4
so = 4/3 = 1.33 ohm ..
therefore it is clear tht circuit 2 double of 1 .. :)
Post by: Vin on May 09, 2010, 01:20:34 pm
Not really sure. A friend of mine mailed the photos to me. He said something like "Federal Physics." Never heard of it from anyone before.....
ohh i see .. neither did i .. :)
Post by: Fastal on May 09, 2010, 01:43:24 pm
oohk .. i hav a different method .. might get complicated but fairly accurate ..
first of all the resistors are all the same .. so v can assume a specific resistance for each one .. say 2 ohm ..
For circuit 1 ==> total resistance ..
1/2 + 1/2 + 1/2 = 3/2
so = 2/3 = 0.667 ohm..
For Circuit 2 ==> total res. ..
1/4 + 1/2 = 3/4
so = 4/3 = 1.33 ohm ..
therefore it is clear tht circuit 2 double of 1 .. :)
where does it say each resistor is 2 ohms?arent we supposed to use the calculated value fram a(ii)
Post by: Vin on May 09, 2010, 01:51:16 pm
where does it say each resistor is 2 ohms?arent we supposed to use the calculated value fram a(ii)
its not mentioned the resistors are of 2 ohms .. we can assume 2 ohms because they are the same ones being used
however u might use the readings given .. jus fo ur understanding i hav used 2 ohms ... DONT GET CONFUSED!!
I ASSUMED JUS FOR THE SIMPLE REASON because THEY R SIMILAR ;) .. ITS MENTIONED .. IF NOT NEVER ASSUME STUFF !! :) :)
Post by: The Golden Girl =D on May 09, 2010, 02:37:19 pm
I know they aren't the best pictures around there but they might help those looking for info on micrometers and vernier callipers...
i saw how they do it in youtube.com but how will the questions abt these two come ? ...... in other words , what will they ask us to do ?
thx in advance
Post by: Vin on May 09, 2010, 03:01:49 pm
i saw how they do it in youtube.com but how will the questions abt these two come ? ...... in other words , what will they ask us to do ?
thx in advance
they may give a situation and tell u to design an experiment or wat readings to tak or they might give a diagram and tell u to calculate the length ..
Post by: The Golden Girl =D on May 09, 2010, 03:04:36 pm
they may give a situation and tell u to design an experiment or wat readings to tak or they might give a diagram and tell u to calculate the length ..
it's still a bit hard for me to describe how i'll actually use it and take readings ...idk?!!? ???
Post by: bob on May 09, 2010, 03:07:05 pm
Its question 1b from physics m/j/08 paper 6
Q:The cylinder completely covers the marks on the metre rule. Describe, with the aid of
a diagram, how you would judge that the centre of the cylinder is directly above the
10.0 cm mark.
Post by: Vin on May 09, 2010, 03:12:53 pm
HELP! This type of question keeps coming up and i never know what to write! the markscheme just says "clear explanation/diagram" n even though its just a one mark question i still wanna know what to write..PLEASE HELP!
Its question 1b from physics m/j/08 paper 6
Q:The cylinder completely covers the marks on the metre rule. Describe, with the aid of
a diagram, how you would judge that the centre of the cylinder is directly above the
10.0 cm mark.
hav a look at previous posts ..1 or 2 pages before ..
Post by: Ghost Of Highbury on May 09, 2010, 03:13:35 pm
Post by: Fastal on May 09, 2010, 03:22:09 pm
Stick/Attach a pin to the 10.cm mark. place the center of the cylinder exactly on the pin. remove the pinwhile removing the pin, wont there be errors?
Post by: Ghost Of Highbury on May 09, 2010, 03:23:28 pm
Post by: Fastal on May 09, 2010, 03:27:34 pm
wat errors? once the cylinder is placed, the pin can be removed...or if u have doubts, let it be dere and carry on the experiment.
wont the pin have weight?
how would you remove the pin? are we making a whole in the cylinder and ruler. i dont get it.
Post by: Ghost Of Highbury on May 09, 2010, 03:34:57 pm
check the image. with the weight of the metal cylinder, it wud be easy to just slip it out with no movements from the cylinder.
Post by: Fastal on May 09, 2010, 03:40:12 pm
the pin is very lightweight compared to the metal cylinder...its extremely thin. the optic pin or thinner than that..how would you place the cylinder exactly on the pin?
check the image. with the weight of the metal cylinder, it wud be easy to just slip it out with no movements from the cylinder.
Post by: Ghost Of Highbury on May 09, 2010, 03:46:33 pm
If you avoid parallax error, it will be placed exactly on the pin (@10.0 cm mark)
Post by: Fastal on May 09, 2010, 03:47:17 pm
find radius
and make sure where the markings end, its 10 cm +the radius
Post by: Ghost Of Highbury on May 09, 2010, 03:48:48 pm
what about this idea?
it involves the same idea of using the pin. in both ways u have to find the center (or the radius).
any wud do..
Post by: Fastal on May 09, 2010, 04:08:46 pm
it involves the same idea of using the pin. in both ways u have to find the center (or the radius).
any wud do..
well it avoids the taking the pin out part, which may cause the cylinder to move a little
Post by: Ghost Of Highbury on May 09, 2010, 04:10:46 pm
Post by: Baladya on May 09, 2010, 05:33:21 pm
Thanks ;)
Post by: Vin on May 09, 2010, 05:39:27 pm
As dry cloth has air .. body stays warm as air is a bad conductor of heat ..:)
Post by: Naruto123 on May 09, 2010, 05:51:33 pm
What are the important instruments for physics ppr 6
because recently deyr have been VErnier scale and micrometer screw gauge poppin up
so all unhheard instruments can u guyz name ?
thx :P
Post by: holtadit on May 09, 2010, 05:53:42 pm
hey guyz lsn
What are the important instruments for physics ppr 6
because recently deyr have been VErnier scale and micrometer screw gauge poppin up
so all unhheard instruments can u guyz name ?
thx :P
Go to youtube and search for micrometer and vernier callipers. There will be several videos showing you how to use each.
Post by: Naruto123 on May 09, 2010, 05:58:31 pm
thx
Post by: Vin on May 09, 2010, 06:01:08 pm
lol i knw how yo use dem bt i wanna know if deyr r any oder such instruments i need to knw abt
thx
I dont think so .. :) stick to them for now .. :P
Post by: Naruto123 on May 09, 2010, 06:05:52 pm
okieee :P
Post by: Baladya on May 09, 2010, 06:11:50 pm
A piece cloth soaked in water does totally opposite of insulation .. water molecules evaporate and take away the heat energy with them (the heat is used up to convert water to vapor as the kinetic energy of of molecules is enough to break the water bond) . this is good wen a body is to be kept cold .. :)
As dry cloth has air .. body stays warm as air is a bad conductor of heat ..:)
And the molecules with the less energy are the ones left over which makes it cold.... bla bla. Ya man i understood that :D Just got mixed up :P
Thanks ;)
And plz stop answering people so fast, give us a chance too xD ;D jk ehehhhehe
Post by: Naruto123 on May 09, 2010, 06:18:48 pm
http://www.freeexampapers.us/IGCSE/Physics/CIE/2005%20Nov/0625_w05_qp_6.pdf
q 2 a
Post by: Vin on May 09, 2010, 06:26:42 pm
i knw this has been answered and i still dunt get it plz can any 1 explain ???????
http://www.freeexampapers.us/IGCSE/Physics/CIE/2005%20Nov/0625_w05_qp_6.pdf
q 2 a
Baladya y dont u answer this one .. :P
Post by: Naruto123 on May 09, 2010, 06:36:40 pm
Baladya y dont u answer this one .. :Plol it duznt matter who answers plz explain ?
Post by: Vin on May 09, 2010, 06:39:30 pm
Post by: Naruto123 on May 09, 2010, 06:43:58 pm
markin scheme says this
2 (a) correct symbols for resistor, voltmeter and ammeter 1
correct connections between resistors AB and BC in series with
CD in parallel with both 1
voltmeter and ammeter correctly positioned
Post by: Naruto123 on May 09, 2010, 06:44:30 pm
Post by: the_grim_reaper on May 09, 2010, 06:48:33 pm
Plus why is it necessary to use a DC voltage between the cathode and anode to create cathode rays in a vaccum?????
Post by: Vin on May 09, 2010, 07:31:25 pm
ya bt is this da answer so simple :o ???
markin scheme says this
2 (a) correct symbols for resistor, voltmeter and ammeter 1
correct connections between resistors AB and BC in series with
CD in parallel with both 1
voltmeter and ammeter correctly positioned
i see wat u say .. Thanks for correctin .. sorry .. how about this ?? :) :)
Post by: Vin on May 09, 2010, 07:38:32 pm
Really sorry guys but I still don't get the pin and cylinder thing. You keep the cylinder on the ruler and insert the pin in the gap between them or what????? Please elaborate!!!
Plus why is it necessary to use a DC voltage between the cathode and anode to create cathode rays in a vaccum?????
You place (stick) the pin horizontally, coinciding the mark on the ruler .. u place the cylinder over the pin .. u want me to show u a drawing ??
If u use a.c u wont get a steady ray .. ur cathode and anode would constantly be changing ..
Post by: Baladya on May 09, 2010, 08:07:11 pm
I need to study A LOT so m not always on so i can only answer the questions that i see unanswered yet :P
Post by: Vin on May 09, 2010, 08:13:03 pm
You wont get a chance until im here .. :P lol ..:D
By the way how is prep for the exams .. im kinda getting tensed now .. :(
Post by: Malak on May 09, 2010, 08:52:11 pm
Thx alot :D
Post by: SEL123 on May 09, 2010, 08:52:38 pm
QUestion 3
V- "Extend the straight line EF within the outline of the block to a point I. The distance FI must be exactly equal to b"
Whaaaaaaaaaaat?
b = FH
H --> p3 and p4 extended to the block
if you can explain the rest of the questions on this page I'd really appreciate it
How can FH and FI be equal
I don't get it
I attached it here
Post by: SEL123 on May 09, 2010, 08:54:48 pm
The sliding contact for a variable resistor??
Okay..look
So if the current is coming from the left (conventional current)
If you slide the contact to the left, the resistance decreases---> current increases
If you slide it to the right, the resistance increases
Just imagine it as the resistor getting bigger
Post by: Vin on May 09, 2010, 08:55:24 pm
Post by: Saladin on May 09, 2010, 09:01:12 pm
Can someone PLEASE help me with may june 06 PAPER 6 PHYSICS igcse
QUestion 3
V- "Extend the straight line EF within the outline of the block to a point I. The distance FI must be exactly equal to b"
Whaaaaaaaaaaat?
b = FH
H --> p3 and p4 extended to the block
if you can explain the rest of the questions on this page I'd really appreciate it
How can FH and FI be equal
I don't get it
I attached it here
hi5, u use gmail!
Post by: the_grim_reaper on May 09, 2010, 09:05:55 pm
Quote
ou place (stick) the pin horizontally, coinciding the mark on the ruler .. u place the cylinder over the pin .. u want me to show u a drawing ??
Yep I've got it thank you but I still don't get 1 very little thing. How does it prove that the centre is on the 10 cm mark?? :P
Post by: Vin on May 09, 2010, 09:06:57 pm
Can someone PLEASE help me with may june 06 PAPER 6 PHYSICS igcse
QUestion 3
V- "Extend the straight line EF within the outline of the block to a point I. The distance FI must be exactly equal to b"
Whaaaaaaaaaaat?
b = FH
H --> p3 and p4 extended to the block
if you can explain the rest of the questions on this page I'd really appreciate it
How can FH and FI be equal
I don't get it
I attached it here
HERE .. temme if u wan nythin more .. :)
Post by: SEL123 on May 09, 2010, 09:08:39 pm
Post by: Vin on May 09, 2010, 09:09:48 pm
Yep I've got it thank you but I still don't get 1 very little thing. How does it prove that the centre is on the 10 cm mark?? :P
for tht u mark a centre line (diameter) of the cylinder if u wan .. so the pin n the diameter sld coincide .. view frm 90o to avoid parallax error .. ;)
Post by: Vin on May 09, 2010, 09:11:27 pm
But if you measure HF and FI they're not equal...
ya so u hatva draw them in a manner so tht they are equal .. i cant do tht on the comp ..
Post by: Vin on May 09, 2010, 09:13:18 pm
hi5, u use gmail!
lol .. :D
Post by: SEL123 on May 09, 2010, 09:14:17 pm
triangle method seen [1]
More than ½ line used [1]
Gradient value correct
"triangle method seen [1]", is that y2-y1/x2-x1??
But its not possible for them to be equal...
If FI touches the line..its going to be longer
I was thinking possible that FI would be = b (4.3 cm)
And by that, it would reach a bit after the midpart of the block
Would that be wrong..?
"hi5, u use gmail!"
Haha! Yeah, I do (mhmm...stalker :P)
Post by: Vin on May 09, 2010, 09:19:29 pm
Can anyone explain The sliding contact thing...Like placing it in which position increases/decreases resistance bla bla...
Thx alot :D
A has more resistance .. winter 06 paper6 .. :P
Post by: Vin on May 09, 2010, 09:29:52 pm
And for getting the gradient they say :
I was thinking possible that FI would be = b (4.3 cm)
And by that, it would reach a bit after the midpart of the block
Would that be wrong..?
wat gradient r u talkin abt ??
nyway .. i drew on paper right now .. its possible .. its too near to G tho .. n FI is supposed to be equal to B ..
Post by: the_grim_reaper on May 09, 2010, 09:41:08 pm
Quote
for tht u mark a centre line (diameter) of the cylinder if u wan .. so the pin n the diameter sld coincide .. view frm 90o to avoid parallax error ..
THank you so much!!!! + rep! I am very thankful to you! Just one more question. I'll get a mark for this right??? :D.
Post by: Malak on May 09, 2010, 09:52:46 pm
@ Vin....Hehe i knew tht answer but was jst making sure abt the sliding contact stuff..But thx nyway:P
Post by: Vin on May 09, 2010, 09:56:12 pm
Thx Sel...
@ Vin....Hehe i knew tht answer but was jst making sure abt the sliding contact stuff..But thx nyway:P
i thought so .. id seen u answering in the past n ur smart .. so even i didnt care much to ans jus pasted a diag.. :P lol
Post by: 6394 on May 10, 2010, 02:42:12 am
??? give 2 reasons why the fulcrum should have a sharp edge!!!
i dnt hve ms for this cos its 2 old <may 1992> ;)
Post by: 6394 on May 10, 2010, 03:03:12 am
Post by: nizzy on May 10, 2010, 03:18:48 am
a diagram, how you would judge that the centre of the cylinder is directly above the
10.0 cm mark.
I saw this type of questions some other places, this was s08 in paper 6, and the MS only says: (b) clear explanation/diagram [1]
So, what would be the diagram/explanation ?
Thank you.
Post by: holtadit on May 10, 2010, 03:51:07 am
The cylinder completely covers the marks on the metre rule. Describe, with the aid of
a diagram, how you would judge that the centre of the cylinder is directly above the
10.0 cm mark.
I saw this type of questions some other places, this was s08 in paper 6, and the MS only says: (b) clear explanation/diagram [1]
So, what would be the diagram/explanation ?
Thank you.
https://studentforums.biz/index.php/topic,6468.285.html
Your question has been answered on this page. Just scroll downwards.
Post by: 6394 on May 10, 2010, 04:16:16 am
can ny1 plz draw n show???? on this kind of diag. :)
Thanks ;D
Post by: 6394 on May 10, 2010, 04:43:40 am
Post by: Adzel on May 10, 2010, 05:07:37 am
Post by: 6394 on May 10, 2010, 05:08:59 am
Post by: Adzel on May 10, 2010, 05:14:10 am
cn any1 answer this plz?
??? give 2 reasons why the fulcrum should have a sharp edge!!!
i dnt hve ms for this cos its 2 old <may 1992> ;)
1. So the rule can move more freely.
2. To easily identify the center.
Post by: SEL123 on May 10, 2010, 05:37:30 am
Like...Negative on the right and positive on the left, or the other way around
Post by: Adzel on May 10, 2010, 05:38:52 am
Post by: SEL123 on May 10, 2010, 05:46:18 am
I'm always seeing different thermistors...
One time, the line going through the resistor goes from left to right, the other time, right to left
Which should I use?!?!?
Post by: Adzel on May 10, 2010, 05:50:42 am
Post by: The Golden Girl =D on May 10, 2010, 05:54:49 am
thx in advance
Post by: SEL123 on May 10, 2010, 06:13:00 am
Post by: The Golden Girl =D on May 10, 2010, 06:24:35 am
How do you connect a voltmeter to measure the p.d across two lamps in PARALLEL?
i'll answer ur question but plz answer me mine ,k?
umm the voltmeter is always connected in parallel to lamps/resistors ..in this circuit , u draw another parallel line that looks the same as the ones u drew the lamps on but instead u put a voltmeter
hope i helped
Post by: SEL123 on May 10, 2010, 06:35:28 am
Can you re-explain that?
I didn't reallly get it...
Post by: SEL123 on May 10, 2010, 06:39:41 am
So T/s starts from 1.0
Each 5 squares = .1
So it goes:
1.0 1.1. 1.2 alll the way up till 2
for l/cm
You can start from 40
each square is = to 1
thats the only way you can do it
Post by: holtadit on May 10, 2010, 06:48:14 am
Question 1 c i
Please explain the answer - MS is useless
Post by: haris94 on May 10, 2010, 07:03:39 am
at the start, the temperature of the water is 68
suppose room temperature is 25
the difference is 43
now in the final minute, the temperature of the water is 29
the difference in temp between the water and room temperature is now only 5
your answers of t1 and t2 in b part prove the above
so the theory "rate of cooling of the hot water at any time depends on the difference between the temperature of the water at that time and room temperature" is right according to the answer
Post by: SEL123 on May 10, 2010, 07:04:27 am
At 0 seconds, the temperature is 68, then at 20 its 53
There's a temperature difference of 15 degrees
68 degrees is very far from the room temperature, so the change in the next 30 seconds is very large
But as the temperature gets closer to room temperature, the change is less.Eg:
At 270 seconds, the temperature was 28.5
At 300, its at 28
The increase is only 0.5
Post by: holtadit on May 10, 2010, 07:06:43 am
yes, answer does support the theory
at the start, the temperature of the water is 68
suppose room temperature is 25
the difference is 43
now in the final minute, the temperature of the water is 29
the difference in temp between the water and room temperature is now only 5
your answers of t1 and t2 in b part prove the above
so theory is right according to the answer
So the greater the difference between room temp. and the temp. of the water the GREATER THE RATE OF COOLING ?
Post by: thenewkid™ on May 10, 2010, 07:07:39 am
Quote
Alright I'm trying it now..
Can you re-explain that?
I didn't reallly get it...
hope this is correct
Post by: IG4ever on May 10, 2010, 07:08:59 am
Post by: haris94 on May 10, 2010, 07:09:19 am
So the greater the difference between room temp. and the temp. of the water the GREATER THE RATE OF COOLING ?
exactly
thats what the theory says in the question
we just hv to prove it
Post by: SEL123 on May 10, 2010, 07:12:28 am
I'm taking the Paper 6 exam tomorrow
I saw the october november 09 one
It was beyond easy
Does anyone think ours would be easier too??
Post by: The Golden Girl =D on May 10, 2010, 07:13:54 am
Alright
So T/s starts from 1.0
Each 5 squares = .1
So it goes:
1.0 1.1. 1.2 alll the way up till 2
for l/cm
You can start from 40
each square is = to 1
thats the only way you can do it
1.0 1.1. 1.2 alll the way up till 2 do i start it with one or 0 ?
umm okay here a somewhat drawin that inshAllah might be useful :P
l l this is a baterry k
----1---- this is lamp 1
----2---- this is lamp 2
----3---- this is the voltmeter
got it ?
By the way i kno that i didn't draw coppper wires that complete the circuit .....but if u want the drawing to be complete u chould connect the gaps i had with copper wires ,k?
Post by: thenewkid™ on May 10, 2010, 07:14:46 am
Post by: haris94 on May 10, 2010, 07:20:13 am
this is from winter 08 p6
Post by: The Golden Girl =D on May 10, 2010, 07:21:18 am
i really hope so i have it 2morrow as well
just so u kno everyone around the world is gonna have it tomorrow too ......... an evidence of this :P , is that my friend livin in oman has physics paper 6 tomorrow at the same timin , u see ::)
Post by: haris94 on May 10, 2010, 07:23:56 am
just so u kno everyone around the world is gonna have it tomorrow too ......... an evidence of this :P , is that my friend livin in oman has physics paper 6 tomorrow at the same timin , u see ::)
agreed
physics p6 is tomorrow for all igcse students around the the world
though not always same timing
Post by: thenewkid™ on May 10, 2010, 07:24:44 am
Post by: The Golden Girl =D on May 10, 2010, 07:27:37 am
then wats the fuss abt variant 1 and variant 2?
my friends who r egyptians always have pastpapers with varient one cuz in egypt they take varient 1 which is soo similar to varient 2 but maybe 2-3 questions r different , u see ........... but as for where i live everyone does varient 2 .....so i guess there isn't much of a fuss here...
Post by: thenewkid™ on May 10, 2010, 07:29:25 am
Post by: Hesham Mhd on May 10, 2010, 07:31:52 am
Post by: haris94 on May 10, 2010, 07:32:36 am
im giving variant 2 (hope its easier than variant 1 :P)
good luck to us all!
Post by: The Golden Girl =D on May 10, 2010, 07:33:33 am
Hi, if they asked yu to draw a GRAPH, how can you know if yu should draw a line of best fit? because sometimes it can also be drawn as a curve? O_o
i'm a bit confused on this too -_-
Post by: Vin on May 10, 2010, 07:34:00 am
can anyone pls tell me how to draw the circuit in question 2 a
this is from winter 08 p6
Post by: haris94 on May 10, 2010, 07:35:16 am
Hi, if they asked yu to draw a GRAPH, how can you know if yu should draw a line of best fit? because sometimes it can also be drawn as a curve? O_o
if they want line of best fit they will mention it
sometimes they ask to draw curve of best fit
Post by: thenewkid™ on May 10, 2010, 07:35:41 am
Post by: holtadit on May 10, 2010, 07:35:48 am
4 c the MS says that the refractive index is 1.43. I get 1.78.
All my measurements are correct.
WHATS WRONG !!!!
Post by: Vin on May 10, 2010, 07:36:14 am
Hi, if they asked yu to draw a GRAPH, how can you know if yu should draw a line of best fit? because sometimes it can also be drawn as a curve? O_o
Usually they mention 'draw a best fit line/curve' .. if not thn u yourself have to judge wat to do ..
Post by: haris94 on May 10, 2010, 07:37:44 am
Post by: Vin on May 10, 2010, 07:39:36 am
Summer 2008
4 c the MS says that the refractive index is 1.43. I get 1.78.
All my measurements are correct.
WHATS WRONG !!!!
lol i got 1.64 .. i think it depends on the size of the printout .. if its not according to pdf the size might change ..
Post by: Vin on May 10, 2010, 07:43:23 am
Thanks vin
sure .. :)
Guys any beautiful ideas for 1 b) ..
Post by: haris94 on May 10, 2010, 07:43:47 am
i got these readings
2.2*4.0
1.3*4.4
=1.50
Post by: holtadit on May 10, 2010, 07:46:53 am
yea it depends on your printout size
i got these readings
2.2*4.0
1.3*4.4
=1.50
Phew ! Thanks people +rep Vin
Haris I will + rep you later but Vin first since he answered faster. :)
Post by: Fastal on May 10, 2010, 07:47:49 am
sure .. :)
Guys any beautiful ideas for 1 b) ..
use thick rigid wire toconnect electrodes. remove electrodes from beaker vertically. measure.
this is what i would write at least..
Post by: holtadit on May 10, 2010, 07:48:19 am
sure .. :)
Guys any beautiful ideas for 1 b) ..
Place a wooden block of length x (whatever x is :P) in between the electrodes.
Post by: Fastal on May 10, 2010, 07:49:56 am
Place a wooden block of length x (whatever x is :P) in between the electrodes.
i dont get it
Post by: thenewkid™ on May 10, 2010, 07:50:55 am
Post by: Vin on May 10, 2010, 07:52:37 am
Place a wooden block of length x (whatever x is :P) in between the electrodes.
i thought so the same .. wood is also a non conductor .. but how would u get a block of the same size.. ?? :P
Post by: haris94 on May 10, 2010, 07:54:39 am
Post by: Vin on May 10, 2010, 07:54:49 am
use thick rigid wire toconnect electrodes. remove electrodes from beaker vertically. measure.
this is what i would write at least..
wont the resistance decrease .. ??
Post by: holtadit on May 10, 2010, 07:56:29 am
i thought so the same .. wood is also a non conductor .. but how would u get a block of the same size.. ?? :P
Supposing the gap needs to be 1 cm large.
Cut a wood block of 1 cm length. Then place the block into the beaker and shove it in between the electrodes.
DONE !
Post by: thenewkid™ on May 10, 2010, 07:56:59 am
Quote
can u take the electrodes out and measure the distance?
no they hv 2 stay inside
Post by: Fastal on May 10, 2010, 07:59:05 am
wont the resistance decrease .. ??
if you use it from the start of the experiment it wont matter, they are only investigating condution of current through the solution
Post by: Vin on May 10, 2010, 08:00:47 am
if you use it from the start of the experiment it wont matter, they are only investigating condution of current through the solution
yup ur right .. Thanks .. :)
Post by: 6394 on May 10, 2010, 08:08:24 am
Post by: thenewkid™ on May 10, 2010, 08:09:04 am
Post by: 6394 on May 10, 2010, 08:20:52 am
evn an ammeter measures current
Post by: haris94 on May 10, 2010, 08:24:05 am
thank you
Post by: Fastal on May 10, 2010, 08:30:09 am
question 4 b please
thank you
Post by: 6394 on May 10, 2010, 08:34:04 am
HELP PLZZZZZ
??? ??? ???
Post by: rahuldevnani93 on May 10, 2010, 08:54:49 am
May/June 2004 - Q3 c) ii) Should we put a different variable resistor for each lamp in parallel or only one in the beginning.
May/June 2008 - Q1 b)
May/June 2008 - Q2 - Statement is yes, How to justify?
Please reply as soon as possible
http://www.xtremepapers.net/CIE/Cambridge%20IGCSE/0625%20-%20Physics/0625_s04_qp_6.pdf
http://www.xtremepapers.net/CIE/Cambridge%20IGCSE/0625%20-%20Physics/0625_s08_qp_6.pdf
Post by: Fastal on May 10, 2010, 08:55:52 am
3b, its says draw best fit curve, but my teachher said it should be a straigt line
in the marking scheme it says "thin best fit line"
i dont understand. what do i do?
Post by: haris94 on May 10, 2010, 08:57:52 am
i cant understand ques 2 part c!!!
HELP PLZZZZZ
??? ??? ???
both predictions r correct
according to the readings in the table, potential difference in circuit 1 and 2 is more or less same
and in circuit 3, it is approximately half of 1 and 2
Post by: holtadit on May 10, 2010, 08:58:51 am
O/n 08 Paper 6
3b, its says draw best fit curve, but my teachher said it should be a straigt line
in the marking scheme it says "thin best fit line"
i dont understand. what do i do?
A curve is a curve. It has to be a smooth curve like when you draw a cumulative frequency graph in math.
Post by: Vin on May 10, 2010, 09:03:26 am
wat do we use in a thermocouple thermometer galvanometer or ammetre???????
We can use an ammeter , galvanometer and also voltmeter /digital voltmeter :)
Post by: haris94 on May 10, 2010, 09:04:38 am
O/n 08 Paper 6
3b, its says draw best fit curve, but my teachher said it should be a straigt line
in the marking scheme it says "thin best fit line"
i dont understand. what do i do?
i dont understand what the problem is
they say in the ms that it should be a thin line, not necessarily straight
a curve is a line too --- its just a curved line
Post by: Vin on May 10, 2010, 09:17:45 am
i cant understand ques 2 part c!!!
HELP PLZZZZZ
??? ??? ???
2 c) always remember "within the limits of experimental accuracy"
1. look at the readings given in table 2.1 .. this is an open ended question .. ans may be yes / no
for Yes .. values are approx. equal with diff. of 0.08 V (within the limits of experimental accuracy .. thts wat the ques says with in10%)
2.yes .. u say values are approx. half ..
Post by: Vin on May 10, 2010, 09:21:27 am
May/June 2004 - Q1 b) and c)
May/June 2004 - Q3 c) ii) Should we put a different variable resistor for each lamp in parallel or only one in the beginning.
may 2004
Q 1 b) as my fellow mates here said use a wooden block to keep the electrodes in the same dist. .. wood is a bad conductor ..
c) heat generated in wires ..
Q 3 c) jus one !!
Post by: Vin on May 10, 2010, 09:30:39 am
May/June 2008 - Q1 b)
May/June 2008 - Q2 - Statement is yes, How to justify?
Please reply as soon as possible
1 b) discussing this for the 50th time on this thread !!
use a pin n attach to the 10 cm mark .. mark the centre (diameter) if the cylinder with marker .. coincide this mark with the pin (u may also stick another pin on the diameter) .. read from 90o to avoid parallax error .. :)
c) this one has also been discussed ;) .. yes .. I in circuit 1 is double thn 2 .. :)
Post by: Vin on May 10, 2010, 09:32:11 am
both predictions r correct
according to the readings in the table, potential difference in circuit 1 and 2 is more or less same
and in circuit 3, it is approximately half of 1 and 2
sorry didnt see u'd already answered .. :P
Post by: 6394 on May 10, 2010, 09:35:37 am
By the way Thanks ;D ??? :)
Post by: 6394 on May 10, 2010, 09:36:35 am
"within the limits of experimental accuracy"
=D
Post by: princess12 on May 10, 2010, 09:37:15 am
Post by: haris94 on May 10, 2010, 09:40:14 am
sorry didnt see u'd already answered .. :P
no probs...... 8)
for calculating gradient, the ms says
triangle method seen
More than ½ line used
Gradient value correct
what do they mean by "more than 1/2 line used" ??
Post by: Vin on May 10, 2010, 09:41:24 am
this sent LOL
"within the limits of experimental accuracy"
=D
its given in the ques .. meaning tht the readings may vary a little than wat the theory has to say .. due to factors lik heat .. volume .. etc . :)
Post by: Vin on May 10, 2010, 09:45:45 am
no probs...... 8)
for calculating gradient, the ms says
triangle method seen
More than ½ line used
Gradient value correct
what do they mean by "more than 1/2 line used" ??
takin suppose last two readigns of the gradient ..
so tht u get a uniform , accurate gradient ..
Post by: haris94 on May 10, 2010, 09:48:55 am
hmm ok Thanks
Post by: key04 on May 10, 2010, 09:52:33 am
what is the meaning of induce current?
thanks
Post by: 6394 on May 10, 2010, 09:54:37 am
n is it important for the distances 2 be more than 5 cm wen putting the optic pins?????
Thank You in advance
Post by: saleemsamer on May 10, 2010, 10:20:14 am
Post by: key04 on May 10, 2010, 10:21:50 am
EMERGENCY.....................
plz answer my question..
what is induced current???????????? ???
Thanks.....................
Post by: key04 on May 10, 2010, 10:23:38 am
Hope ths help..
Post by: Baladya on May 10, 2010, 10:26:21 am
Everyone...........It is the current u get when u cross magnetic field lines with a conductive wire. This is the process in A.C Generators. U have a magnet, and a wire which is crossing the magnetic field lines. Everytime it crosses it, a current moves thro the wire (INDUCED) and if u have an ammeter in the circuit/wire u will see that there is current
EMERGENCY.....................
plz answer my question..
what is induced current???????????? ???
Thanks.....................
Post by: key04 on May 10, 2010, 10:28:05 am
Post by: key04 on May 10, 2010, 10:29:17 am
saleem i hope this help
Post by: saleemsamer on May 10, 2010, 10:30:29 am
file:///C:/Documents%20and%20Settings/Owner/Desktop/p6.PNGcan u plz upload the file cuz i cant see it this is the link from ur pc
saleem i hope this help
Post by: haris94 on May 10, 2010, 10:33:19 am
while posting, click on additional options and then attach the file
Thanks
Post by: Vin on May 10, 2010, 10:34:37 am
i have something to ask...
what is the meaning of induce current?
thanks
When electric/magnetic field lines cut each other in a coil a small amount of current is produced which deflects the reading on an ammeter ..
when u insert a magnet to and fro into a coil. some current is produced
transformers work on electromagnetic induction .. where the field lines primary coil cuts the secondary coil to either 'step up' a current or step down step up means to hav a small amount of voltage to be increased using a lesser input voltage , step down is exactly opposite .. :)
Post by: key04 on May 10, 2010, 10:35:37 am
Post by: key04 on May 10, 2010, 10:36:40 am
u guys r so generous for helping me out for everything that i ask..
Post by: saleemsamer on May 10, 2010, 10:38:35 am
ok i try though im not so sureTYVM :D
Post by: key04 on May 10, 2010, 10:39:28 am
which one of this is the correct answer?
Post by: key04 on May 10, 2010, 10:39:55 am
Post by: rawr123 on May 10, 2010, 10:40:26 am
question 1 (c) and 1 (d)
Thanks!
Post by: Vin on May 10, 2010, 10:40:45 am
ok i try though im not so sure
PLAGIARISM !! lol :D :D
here .. thts a bit incorrect.. :)
Post by: 6394 on May 10, 2010, 10:41:41 am
?????
thnkz
Post by: key04 on May 10, 2010, 10:41:47 am
u've been a great help
Post by: key04 on May 10, 2010, 10:43:19 am
Post by: Vin on May 10, 2010, 10:46:45 am
Please help me with http://www.freeexampapers.us/IGCSE/Physics/CIE/2005%20Nov/0625_w05_qp_6.pdf
question 1 (c) and 1 (d)
Thanks!
here .. sorry my handwriting s real bad ..
c) phy8
d) picture 12 .. "Measure the distance 'd' at 100 cm end from the bench using a ruler and a set square to make sure ruler's horizontal .. " ;)
Post by: Vin on May 10, 2010, 10:48:06 am
@Eisya cn i noe which yr is this frm
?????
thnkz
Post by: rawr123 on May 10, 2010, 10:50:01 am
here .. sorry my handwriting s real bad ..
c) phy8
d) picture 12 .. "Measure the distance 'd' at 100 cm end from the bench using a ruler and a set square to make sure ruler's horizontal .. " ;)
I understood everything but what did you mean by a set square?
thanks alot <3
Post by: Vin on May 10, 2010, 10:54:25 am
I understood everything but what did you mean by a set square?
thanks alot <3
You kno wats a set square right ? so usually its used to check whether a straight edged object (here ruler) is parallel to the base or exactly horizontal .. in such kind of ques .. ;)
Post by: rawr123 on May 10, 2010, 10:55:37 am
You kno wats a set square right ? so usually its used to check whether a straight edged object (here ruler) is parallel to the base or exactly horizontal .. in such kind of ques .. ;)
Ahh okay thanks alot!! ;D.
Also i got 3 posts heres a rep :).
Post by: PeaceMaker on May 10, 2010, 11:00:45 am
Thats all of my doubts of paper 6. Went through 2003 - 2009 and found that these are my problems.
Post by: saleemsamer on May 10, 2010, 11:02:36 am
Post by: rawr123 on May 10, 2010, 11:08:18 am
How do you calculate the rise and fall of a temperature? Also, Question 1, Q.3B, 4B how do you take the measurements?, 2009 OCT/NOV, i can't seem to understand what to do exactly. Also, what to do when you are asked to draw to rectangular blocks to measure something?
Thats all of my doubts of paper 6. Went through 2003 - 2009 and found that these are my problems.
I have the same problem with the rectangular blocks :(.
Post by: 6394 on May 10, 2010, 11:09:05 am
measure de distance "d" and "l" using a rule n set square and den using tan theta find the angle
hope m correct
:) ;) :P
Post by: dodi23 on May 10, 2010, 11:14:21 am
ok i got a question "Draw the line of the best fit on your graph" do we dra a straight line or what?jus draw a straight line in whinch the number of points on top of line is equal 2 number of points under the line (line of best fit) ;) :)
Post by: Vin on May 10, 2010, 11:14:29 am
How do you calculate the rise and fall of a temperature?
Rise and fall in temperature ?? look at ques 5 in the attached paper .. b) i) Initial water temperature is 22o C .. when the cylinder is added Final temp = 36 oC .. so 36 - 22 = 14oC
.. ii) Initial temp of cylinder is 100oC .. when place in water (which is 36oC)
= 100 - 36 = 64oC .. jus read the ques properly ..!! :) :)
Also, Question 1, Q.3B, 4B how do you take the measurements?, 2009 OCT/NOV, i can't seem to understand what to do exactly. Also, what to do when you are asked to draw to rectangular blocks to measure something?
Thats all of my doubts of paper 6. Went through 2003 - 2009 and found that these are my problems.
u obvi. measure by scale !!.. if ur wondering the ms ans differ because the printout which u may hav wld not be according to the pdf so the sizes may differ .. :)
Post by: Vin on May 10, 2010, 11:17:51 am
i thnk for ques <0625/06/O/N/05> 1-d u hve 2 do it thid way (lok at de pic)
measure de distance "d" and "l" using a rule n set square and den using tan theta find the angle
hope m correct
:) ;) :P
dont worry u r right .. but the ques says "suggest another method of investigating as reliably as possible the extent by which the rule is pulled down by the masses."
u dont need to worry about the angles .. :)
Post by: saleemsamer on May 10, 2010, 11:19:26 am
jus draw a straight line in whinch the number of points on top of line is equal 2 number of points under the line (line of best fit) ;) :)thx :D
Post by: big mac on May 10, 2010, 11:20:00 am
By the way, this question is mainly in holly Physics paper 6.
Post by: 6394 on May 10, 2010, 11:22:29 am
Post by: holtadit on May 10, 2010, 11:25:02 am
y do we need to view the bases of the pins when lining them up????????????
since they may not be vertical
Post by: Vin on May 10, 2010, 11:25:41 am
i can help u if u ask a specific question frm any paper .. :) :)
y dont u ask here https://studentforums.biz/index.php/board,80.0.html
Post by: Malak on May 10, 2010, 11:27:44 am
By the way...I never really saw those in P6 ?
Post by: ruruiw 60984 on May 10, 2010, 11:31:02 am
:)
Post by: dodi23 on May 10, 2010, 11:31:34 am
Hey, I have a problem with the ''light'' rays, topic, like when they give you a paper and set of question, like '' draw the normal line on the grid above '' I really have no clue how this works, I know it's so complicated to actually explain it why you're typing, so do any of you guys know a website or something for that kind off stuff? like drawing normal lines etc... with pictures and explainations, any link would be useful, thanks.
By the way, this question is mainly in holly Physics paper 6.
http://id.mind.net/~zona/mstm/physics/light/rayOptics/reflection/reflection1.html
hope it helps :) ;D ;)
Post by: dodi23 on May 10, 2010, 11:32:58 am
how do u find the mid point of a lens?
:)
its just usually there in p6
Post by: Vin on May 10, 2010, 11:34:42 am
For "SEL123" .. this is from may june 2004 .. q 3 . ;)
Post by: 6394 on May 10, 2010, 11:36:28 am
Post by: 6394 on May 10, 2010, 11:38:54 am
Thanks <ruruiw 60984>
nyc ques!!!
:P
Post by: ruruiw 60984 on May 10, 2010, 11:39:32 am
so may someone type it , i would be very thankful.. :D
Post by: 6394 on May 10, 2010, 11:41:17 am
n i really wanna noe this aswel
Post by: key04 on May 10, 2010, 11:41:42 am
Good luck 4 PHY paper 6 tomorrow!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Post by: 6394 on May 10, 2010, 11:42:06 am
:P
Post by: Vin on May 10, 2010, 11:42:18 am
I have the same problem with the rectangular blocks :(.
u simply measure the dist .. :)
Post by: 6394 on May 10, 2010, 11:42:51 am
Post by: key04 on May 10, 2010, 11:45:10 am
u simply measure the dist .. :)sorry but which question paper is this??????????
Post by: 6394 on May 10, 2010, 11:46:33 am
<The cylinder completely covers the marks on the metre rule. Describe, with the aid of
a diagram, how you would judge that the centre of the cylinder is directly above the
10.0 cm mark.>
thnk u sooo mch for ansering this 1!!!! :) :) :) :) :) :)
Post by: Vin on May 10, 2010, 11:47:44 am
Can anyone help me with the ray(lens) diagrams...Like when the image is inverted or virtual, upright, diminshed n bla bla...
By the way...I never really saw those in P6 ?
http://astarmathsandphysics.com/igcse_physics_notes/igcse_physics_notes_drawing_ray_diagrams_for_thin_lenses.html
i only kno this website !! .. :)
Post by: rawr123 on May 10, 2010, 11:48:54 am
u simply measure the dist .. :)
Thanks alot ;D
@Eisya http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Jun/0625_s09_qp_6.pdf
number 1 (a) (iii)
Post by: Malak on May 10, 2010, 11:49:15 am
u simply measure the dist .. :)
Hey can we place the rule inside the two blocks wen measuring the height...
this way :
http://img696.imageshack.us/img696/1817/78590551.png (http://img696.imageshack.us/img696/1817/78590551.png)
Post by: key04 on May 10, 2010, 11:49:51 am
Thanks alot ;D
@Eisya http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Jun/0625_s09_qp_6.pdf
number 1 (a) (iii)
Thanks rawr123
Post by: Vin on May 10, 2010, 11:50:30 am
sorry but which question paper is this??????????
oh i jus made it up .. :)
Post by: rawr123 on May 10, 2010, 11:51:21 am
Hey can we place the rule inside the two blocks wen measuring the height...
this way :
http://img696.imageshack.us/img696/1817/78590551.png (http://img696.imageshack.us/img696/1817/78590551.png)
Yes you can although i suggest putting the ruler outside and measuring between the top part of the bottom wooden block and the bottom part of the top block.
Your welcome Eisya :)
Post by: Shazizzzle on May 10, 2010, 11:51:56 am
For example, when measuring u and v in a lens diagram, do we use cm or mm?
Post by: Vin on May 10, 2010, 11:52:10 am
Thanks alot ;D
@Eisya http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Jun/0625_s09_qp_6.pdf
number 1 (a) (iii)
i knew i'd solved it in some paper !! .. :P
Post by: Vin on May 10, 2010, 11:53:12 am
In paper 6, the mark scheme in some years prefers using cm, and in others, only mm.
For example, when measuring u and v in a lens diagram, do we use cm or mm?
Never worry of such small stuff !! .. :) irs ok as long as ur ans is right .. :)
Post by: key04 on May 10, 2010, 11:54:57 am
i knew i'd solved it in some paper !! .. :Pbut u said u made up d ques????
it's from may june 2009 paper 6
Post by: key04 on May 10, 2010, 11:56:25 am
Never worry of such small stuff !! .. :) irs ok as long as ur ans is right .. :)they won't cut our marks?
bcoz i got confuse with this too...
Post by: haris94 on May 10, 2010, 11:58:09 am
unless it is specified which unit to use
Post by: rawr123 on May 10, 2010, 12:00:42 pm
they won't cut our marks?
bcoz i got confuse with this too...
It doesn't matter they'll put them both correct (whether in mm or cm) BUT if you want to use it in some equation you better make sure all the measurements are in cm or mm :).
Post by: Vin on May 10, 2010, 12:01:26 pm
but u said u made up d ques????
it's from may june 2009 paper 6
i neva said i made up the ques .. how does it matter.. i think i had at somewhere at the back of my mind .. =)
Post by: Shazizzzle on May 10, 2010, 12:02:57 pm
_____________________________
Rather than
*bump**bump**bump*
OR *bump**straight line at bottom**bump*
There was such a question here earlier.
Post by: Vin on May 10, 2010, 12:05:47 pm
*bump**straight line at bottom**bump* . is wen ac is rectified ..;)
Post by: key04 on May 10, 2010, 12:12:28 pm
It doesn't matter they'll put them both correct (whether in mm or cm) BUT if you want to use it in some equation you better make sure all the measurements are in cm or mm :).Thanks
Post by: key04 on May 10, 2010, 12:12:44 pm
no, they wont cut marksThanks
unless it is specified which unit to use
Post by: key04 on May 10, 2010, 12:13:18 pm
i neva said i made up the ques .. how does it matter.. i think i had at somewhere at the back of my mind .. =)it doesn't matter at all...
lol
Post by: Priceless on May 10, 2010, 12:15:18 pm
yup dc graph is straight .. __________________
*bump**straight line at bottom**bump* . is wen ac is rectified ..;)
who wud hv thot i wud actualy miss physics :P ::)
All da best guyz..... :)
Post by: Shazizzzle on May 10, 2010, 12:17:02 pm
DC: *straight line*
Diode: *bump* *straight line at bottom* *bump
Diode + Capacitor (smoothing): *bump* *smooth line to next bump (almost straight)* *bump*
Correct?
Post by: 6394 on May 10, 2010, 12:18:02 pm
q1 c and d
ok lok at de image n i will ask de ques as u may nt hav the ques!!!!!
c) In a laboratory exp.,wat wud u do to ensure dat the balls remained in a straight line whisslt u made ur measurements??
u may draw a diag., or draw on fig.1.1, if u wish.
d) describe how u wud take ur measurements in a practical excercise.u may draw a diag.
part a and b i answerd
Post by: ruruiw 60984 on May 10, 2010, 12:21:27 pm
why does the extension becomes greater, even though the mass and the material is the same , its just longer .?
isnt it the same mass .. means same weight of the load == same extension of spring ... :S :S
Post by: ruruiw 60984 on May 10, 2010, 12:23:38 pm
Why does the extension become larger , although the load is of the same mass and material as the previous ,.?
isnt it the same mass == same weight == same extension ??
Post by: Priceless on May 10, 2010, 12:26:52 pm
<nov 92>
q1 c and d
ok lok at de image n i will ask de ques as u may nt hav the ques!!!!!
c) In a laboratory exp.,wat wud u do to ensure dat the balls remained in a straight line whisslt u made ur measurements??
u may draw a diag., or draw on fig.1.1, if u wish.
d) describe how u wud take ur measurements in a practical excercise.u may draw a diag.
part a and b i answerd
for c).....straightness is alwayz checked using a set square
n hw wud u take ur measure measurements....im nt sure :-\
Post by: red_911 on May 10, 2010, 12:27:34 pm
Post by: thenewkid™ on May 10, 2010, 12:29:40 pm
Quote
d) describe how u wud take ur measurements in a practical excercise.u may draw a diag.
part a and b i answerd
you line up the beads between 2 blocks and then measure the distance between the blocks. then divide this by the no of beads
Post by: Priceless on May 10, 2010, 12:29:58 pm
IN november 2008 p6 , Q1 d
Why does the extension become larger , although the load is of the same mass and material as the previous ,.?
isnt it the same mass == same weight == same extension ??
im sorry i did this last yr n i dnt remb da explanation :(
Post by: Shazizzzle on May 10, 2010, 12:30:11 pm
You've got a point there.
I am analyzing.
Wait, why does the extension reduce when the load is submerged? It's because of the pressure being applied in the upward direction due to the water?
Then, if the new load is longer, and is submerged, should have a lower extension?
But wait, they say it's too long to be submerged.
does that mean it is NOT submerged, or are we meant to suppose that it is, to answer? :S ???
Post by: Priceless on May 10, 2010, 12:31:06 pm
please can anyone tell me that do we have to place the test tube vertically and the wooden blocks on the top and bottom or horizontally and wooden blocks to the left and right in june 2009 paper 6 question 1(a)(3) ?
ds wz my ig ppr last yr n i hvnt lukd at da mark scheme but i dnt thnk it shud m8r cz me n my frndz did diff thngz n v still gt A*s...so i dnt thnk it m8rs :)
Post by: red_911 on May 10, 2010, 12:32:51 pm
ds wz my ig ppr last yr n i hvnt lukd at da mark scheme but i dnt thnk it shud m8r cz me n my frndz did diff thngz n v still gt A*s...so i dnt thnk it m8rs :)haha...okey .. thanks dude :D
Post by: thenewkid™ on May 10, 2010, 12:34:14 pm
Quote
d) describe how u wud take ur measurements in a practical excercise.u may draw a diag.diagrams not tht gd sry
part a and b i answerd
you line up the beads between 2 blocks and then measure the distance between the blocks. then divide this by the no of beads
Post by: holtadit on May 10, 2010, 12:34:56 pm
...
This is considered SPAM ruruiw 60984.
Do not repeat.
Post by: 6394 on May 10, 2010, 12:38:05 pm
this method is already given in part a and b
i think it shud be by using vernier callipers or micrometre gauge <maybe>
Post by: Shazizzzle on May 10, 2010, 12:41:25 pm
I can swear the syllabus changed, because Qs in 1995 are like lengthy, weird and never seen before. :-\
Post by: 6394 on May 10, 2010, 12:52:00 pm
<0625/06/O/N/08>
its totally weird
?????????????
Post by: Adzel on May 10, 2010, 12:57:25 pm
S1 = 40.5 cm
S2 = 39.8 cm
b) i) e1 = (S1 – S0).
ii) e2 = (S2 – S0).
Simply find the difference... :P
Post by: Malak on May 10, 2010, 01:01:41 pm
Now, in p6 November 2008 Q 1 part d
why does the extension becomes greater, even though the mass and the material is the same , its just longer .?
isnt it the same mass .. means same weight of the load == same extension of spring ... :S :S
It says the the load is too long to be submerged in the beaker..It means that the extension is longer than before...As for the previous load...it could submerge in the water...And it said its the same mass and same material...But the volume could be different i suppose?
so D-i is greater
Hope u got it ?
Post by: Fastal on May 10, 2010, 01:04:24 pm
Post by: Malak on May 10, 2010, 01:05:47 pm
Don't bother with papers earlier than 2000.Lol..i think the same too...I only solved from 2002..Should i do 2001 and 2000?
I can swear the syllabus changed, because Qs in 1995 are like lengthy, weird and never seen before. :-\
Post by: holtadit on May 10, 2010, 01:06:06 pm
In less than 24 Hours the Physics Paper 6 and other IGCSE examinations will commence. Once this examination is over:
a) You MUST WAIT 24 HOURS before any discussions can take place.
b) ALL DISCUSSIONS must be held in the following thread : https://studentforums.biz/index.php/topic,7273.0.html
Good Luck to You All.
Post by: ruruiw 60984 on May 10, 2010, 01:08:25 pm
i had a problem with my conncetion and thought it didnt post ..
u guys i figured it out .. its actually simple, they measured the externsion from below the load , not the end of the spring, Therefore the longer it is, the larger the length even though it has the same mass
Post by: Fastal on May 10, 2010, 01:10:04 pm
Post by: Malak on May 10, 2010, 01:13:32 pm
Question 1 part a
http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_6.pdf)
Post by: MasterMath on May 10, 2010, 01:20:10 pm
If you have any website for pastpapers for paper 6(PHYSICS) from 2000-2002 with MS or without .. WOULD HELP ALOT!!!
Thanks
Post by: haris94 on May 10, 2010, 01:33:21 pm
http://www.freeexampapers.com/Dndex.php?d=SUdDU0UvUGh5c2ljcy9DSUU=
Post by: Shazizzzle on May 10, 2010, 01:34:47 pm
fiducial marker please? ???
Fiducial point, as in a point for recognition or a point you can familiarize with.
For example, when a pendulum bob is swinging, you pick a point, e.g when the pendulum is the furthermost left, and you begin counting from that point. When it returns to that point again, you count one complete cycle has been done.
Meaning, where to begin counting from.
Post by: haris94 on May 10, 2010, 01:35:54 pm
Can anyone confirm the answer for me
Question 1 part a
http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_6.pdf)
the eye should be 90 degrees to the ruler
Post by: PeaceMaker on May 10, 2010, 01:36:13 pm
Rise and fall in temperature ?? look at ques 5 in the attached paper .. b) i) Initial water temperature is 22o C .. when the cylinder is added Final temp = 36 oC .. so 36 - 22 = 14oC
.. ii) Initial temp of cylinder is 100oC .. when place in water (which is 36oC)
= 100 - 36 = 64oC .. jus read the ques properly ..!! :) :)
u obvi. measure by scale !!.. if ur wondering the ms ans differ because the printout which u may hav wld not be according to the pdf so the sizes may differ .. :)
Thanks! +rep, Well do you know how to solve the other doubs i have which are all from oct/november 2009! Also, how do you measure the illuminated object thingy when it tells you the apparatus is drawn 1/fifth of actual size....what do they mean by it? again thank you and to anyone who answer my doubts.
Post by: Vin on May 10, 2010, 01:36:29 pm
Can anyone confirm the answer for me
Question 1 part a
http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_6.pdf)
how about this .. moved the ruler down .. pasted another eye ..
never solved this one tho .. i better do ..
Post by: Vin on May 10, 2010, 01:40:23 pm
Thanks! +rep, Well do you know how to solve the other doubs i have which are all from oct/november 2009! Also, how do you measure the illuminated object thingy when it tells you the apparatus is drawn 1/fifth of actual size....what do they mean by it? again thank you and to anyone who answer my doubts.
which ques frm oct/november 2009 ??
you jus hav to multiply the measured length by 5 .. they mean the actual thing is 5 times bigger than the fig. drawn .. :)
Post by: nid404 on May 10, 2010, 01:42:07 pm
Post by: Vin on May 10, 2010, 01:43:55 pm
hey guys , Does anyone have a summary or notes to ALL the precautions and stuff for ALL experiments and ..
If you have any website for pastpapers for paper 6(PHYSICS) from 2000-2002 with MS or without .. WOULD HELP ALOT!!!
Thanks
why dont u ask here ..
https://studentforums.biz/index.php/board,80.0.html
Post by: haris94 on May 10, 2010, 01:45:09 pm
how about this .. moved the ruler down .. pasted another eye ..
never solved this one tho .. i better do ..
and also ruler should be closer to the block
i dont know if this matters, but i thought eye should be 90 degrees to the ruler
Post by: Vin on May 10, 2010, 01:46:22 pm
Hey Vin, you're doing a great job :)
Thanks .. im almost done wid phy paper 6 .. duuno wat to do so helping ppl !!.. :)
Post by: Vin on May 10, 2010, 01:51:26 pm
and also ruler should be closer to the block
oh ya sorry didnt think abt tht..
but i thought eye should be 90 degrees to the ruler
i dont get u .. i guess it is 90 degrees right .. ooohh if ur talkin literally srry i couldnt rotate the eye.. :P pasted from the ques paper itself .. :)
Post by: Angelica on May 10, 2010, 01:55:53 pm
hey guys , Does anyone have a summary or notes to ALL the precautions and stuff for ALL experiments and ..www.xtremepapers.com
If you have any website for pastpapers for paper 6(PHYSICS) from 2000-2002 with MS or without .. WOULD HELP ALOT!!!
Thanks
Post by: PeaceMaker on May 10, 2010, 01:59:16 pm
which ques frm oct/november 2009 ??
you jus hav to multiply the measured length by 5 .. they mean the actual thing is 5 times bigger than the fig. drawn .. :)
I posted the Ques in my post a few pages back about all my doubts.
Post by: Vin on May 10, 2010, 02:00:56 pm
Fiducial point, as in a point for recognition or a point you can familiarize with.
For example, when a pendulum bob is swinging, you pick a point, e.g when the pendulum is the furthermost left, and you begin counting from that point. When it returns to that point again, you count one complete cycle has been done.
Meaning, where to begin counting from.
thanks +rep
Post by: NeoMarmar on May 10, 2010, 02:03:43 pm
Well I have one for you. June 2004 Paper 6 Question 3 a
I suppose the ammeter should be on the right and the voltmeter should be on the bottom, correct?
I'm a bit tense so I'm not fully sure.
Post by: haris94 on May 10, 2010, 02:06:39 pm
its from O/N 2002 p6 -- attached
Post by: Baladya on May 10, 2010, 02:07:51 pm
Wow, I didn't know such a forum existed. Too bad I'm too late, though :-\yes Neo
Well I have one for you. June 2004 Paper 6 Question 3 a
I suppose the ammeter should be on the right and the voltmeter should be on the bottom, correct?
I'm a bit tense so I'm not fully sure.
Post by: haris94 on May 10, 2010, 02:08:43 pm
Wow, I didn't know such a forum existed. Too bad I'm too late, though :-\
Well I have one for you. June 2004 Paper 6 Question 3 a
I suppose the ammeter should be on the right and the voltmeter should be on the bottom, correct?
I'm a bit tense so I'm not fully sure.
yup
you're right
voltmeter is always in parallel and ammeter is always connected in series
Post by: Vin on May 10, 2010, 02:08:58 pm
Wow, I didn't know such a forum existed. Too bad I'm too late, though :-\
Welcome to SF !! :)
Post by: Adzel on May 10, 2010, 02:12:26 pm
Q2) part (c) Statment: Position B
Justification: ???????
Post by: Baladya on May 10, 2010, 02:18:06 pm
http://www.xtremepapers.net/CIE/index.php?dir=Cambridge%20IGCSE/0625%20-%20Physics/&file=0625_w09_qp_6.pdf (http://www.xtremepapers.net/CIE/index.php?dir=Cambridge%20IGCSE/0625%20-%20Physics/&file=0625_w09_qp_6.pdf)
Q2) part (c) Statment: Position B
Justification: ???????
Justification means that u should get evidence. So say that in 30 sec it cooled to 56 while A cooled to 65 (so it cooled more) and say that at the end it was 30 while A is 48. This shows that it cooled faster in less time
Post by: Adzel on May 10, 2010, 02:19:59 pm
Post by: saleemsamer on May 10, 2010, 02:27:26 pm
thx in advance :)
Post by: Adzel on May 10, 2010, 02:29:27 pm
Post by: Baladya on May 10, 2010, 02:29:49 pm
oct/nov p6 q3 d i and ii any1 and plz correct answers
thx in advance :)
Which year?
And kindly put a link to it plz..
Post by: xMilishax on May 10, 2010, 02:31:09 pm
oct/nov p6 q3 d i and ii any1 and plz correct answers
thx in advance :)
Which year?
Post by: saleemsamer on May 10, 2010, 02:32:16 pm
Which year?srry 2009\
Post by: Saladin on May 10, 2010, 02:32:53 pm
(d)Using a set square, to measure the change in height
Post by: PeaceMaker on May 10, 2010, 02:36:26 pm
(c) Put the mid point of the protractor at the point between the desk and the metre rule touch. You have to measure the angle from the right.
(d)Using a set square, to measure the change in height
So is that the use of set square? to measure the change in height or change in anything?
Post by: saleemsamer on May 10, 2010, 02:37:18 pm
thx in advance
Post by: Baladya on May 10, 2010, 02:42:11 pm
oct/nov 2009 (sry ::)) p6 q3 d i and ii any1 and plz correct answers
thx in advance
The purpose is to change the resistance...
Post by: Adzel on May 10, 2010, 02:43:01 pm
(c) Put the mid point of the protractor at the point between the desk and the metre rule touch. You have to measure the angle from the right.
(d)Using a set square, to measure the change in height
Can you draw both diagrams please...
Thanks in advanced
Post by: thenewkid™ on May 10, 2010, 02:46:47 pm
Thanks
Post by: Shazizzzle on May 10, 2010, 02:51:04 pm
Okay, seriously, guys, Ask questions! The only way I can test I'm well prepared. :P
Post by: xMilishax on May 10, 2010, 02:51:52 pm
m/j 2006 p6 q 5a
Thanks
You can draw a diagram showing two equal heights from the bench.
Post by: thenewkid™ on May 10, 2010, 02:53:33 pm
Post by: Shazizzzle on May 10, 2010, 02:54:36 pm
m/j 2006 p6 q 5a
Thanks
Umm, you use set squares. Those triangle thingys in your geo box, if you don't know that they are.
Place one in between the stand on the left and the metre rule, and on between a stand you add on your own somewhere in the middle and the metre rule, or between the metre rule and the stand on the left.
The set squares should show a perfect, exact fit at the corners, proving they are 90 deg. and this exactly horizontal.
Post by: xMilishax on May 10, 2010, 02:54:59 pm
Thanks
You're welcome. :)
Post by: Dr.virus007™ on May 10, 2010, 02:55:35 pm
Post by: Shazizzzle on May 10, 2010, 02:55:48 pm
Post by: Malak on May 10, 2010, 02:57:24 pm
The purpose is to change the resistance...
Hey does it matter if the voltmeter is up or down?? No rite...it jst has to b parallel?
Post by: PeaceMaker on May 10, 2010, 02:58:02 pm
Thats all of my doubts of paper 6. Went through 2003 - 2009 and found that these are my problems."
This is my post, i hope most of it gets answered, thanks :D
Post by: thenewkid™ on May 10, 2010, 02:58:41 pm
Quote
A research ship uses an echo-sounder to locate a shoal fish .It receives back an echo 37.1 ms after a sound is transmitted .Work out the depth of the shoal below the ship.(speed of sound in water=1400 m/s).
use speed=d/t
Post by: haris94 on May 10, 2010, 02:58:47 pm
Hey does it matter if the voltmeter is up or down?? No rite...it jst has to b parallel?
nope, doesn't matter
Post by: Adzel on May 10, 2010, 02:59:26 pm
m/j 2006 p6 q 5a
Thanks
Her ya' go...
Post by: Adzel on May 10, 2010, 03:00:46 pm
Can you draw both diagrams please...
Thanks in advanced
Post by: Fastal on May 10, 2010, 03:01:02 pm
A research ship uses an echo-sounder to locate a shoal fish .It receives back an echo 37.1 ms after a sound is transmitted .Work out the depth of the shoal below the ship.(speed of sound in water=1400 m/s).
s=d/t
1400=d/0.371s
d=519.4
since the sound goes to and back
divide by 2
519.4/2=259.7
thus its 260 meters
Post by: Adzel on May 10, 2010, 03:02:46 pm
Post by: Dr.virus007™ on May 10, 2010, 03:02:57 pm
Post by: aoas on May 10, 2010, 03:03:27 pm
oct/nov 2009 (sry ::)) p6 q3 d i and ii any1 and plz correct answers
thx in advance
(http://img686.imageshack.us/img686/6651/94081674.jpg)
Post by: thenewkid™ on May 10, 2010, 03:04:44 pm
Quote
"How do you calculate the rise and fall of a temperature? Also, Question 1, Q.3B, 4B how do you take the measurements?, 2009 OCT/NOV, i can't seem to understand what to do exactly. Also, what to do when you are asked to draw to rectangular blocks to measure something?
in 3b tk the readings off the meters shown in the next diagram
Post by: Dr.virus007™ on May 10, 2010, 03:05:03 pm
When calculating the gradient of a line in PAPER 6 a mark is given for drawing a triangle 'more than half the length of the line'.
The examiners report also refers to the TRIANGLE METHOD alot. What is this method/how does it work.
The only way I know to calc. a gradient is using (y2-y1)/(x2-x1).
For the triangle method......1/2 x Base x Height
Post by: Shazizzzle on May 10, 2010, 03:05:40 pm
"How do you calculate the rise and fall of a temperature? Also, Question 1, Q.3B, 4B how do you take the measurements?, 2009 OCT/NOV, i can't seem to understand what to do exactly. Also, what to do when you are asked to draw to rectangular blocks to measure something?
Thats all of my doubts of paper 6. Went through 2003 - 2009 and found that these are my problems."
This is my post, i hope most of it gets answered, thanks :D
For example, a beaker of water is at 20 deg. C. After adding a heated metal at 100 deg. C, the temp of the water is 32 deg. C, suppose.
temperature rise of the water will be: Final - Initial = 32 - 20 = 12 deg. C.
Similarly, as the temp of the water is now 32, and the heated metal was at 100 deg. C, it's fall in temp will be: Initial - Final = 100 - 32 = 68 deg. C.
For the measurements of Q4 B,
they've asked you to take an average value.
Attempt measuring the diameter of the lens, first horizontally, then vertically.
You might seem to be getting two different values.
Take the average of those values, i.e 1st + 2nd/2 .
Post by: Adzel on May 10, 2010, 03:06:51 pm
Umm, you use set squares. Those triangle thingys in your geo box, if you don't know that they are.
Place one in between the stand on the left and the metre rule, and on between a stand you add on your own somewhere in the middle and the metre rule, or between the metre rule and the stand on the left.
The set squares should show a perfect, exact fit at the corners, proving they are 90 deg. and this exactly horizontal.
Can you draw your diagram please.
Post by: haris94 on May 10, 2010, 03:07:07 pm
O/N 2002 p6
Post by: Dr.virus007™ on May 10, 2010, 03:08:24 pm
s=d/t
1400=d/0.371s
d=519.4
since the sound goes to and back
divide by 2
519.4/2=259.7
thus its 260 meters
the ans iz 26 according to them but i dnt get it(They need the depth*)
Post by: thenewkid™ on May 10, 2010, 03:09:25 pm
Quote
giv me the answer........
check the back of the bk ;)
Post by: Adzel on May 10, 2010, 03:10:59 pm
- OR Repeat the experiment more than once, and get the average.
Post by: Fastal on May 10, 2010, 03:11:26 pm
the ans iz 26 according to them but i dnt get it(They need the depth*)
i was wrong its is 26 meters, got the second millisecond conversion wrong
this is right
s=d/t
1400=d/0.0371s
d=51.94
since the sound goes to and back
divide by 2
51.94/2=25.97
thus its 26.0 meters
Post by: thenewkid™ on May 10, 2010, 03:12:55 pm
Post by: haris94 on May 10, 2010, 03:14:14 pm
@ haris94: - Move pivot to 50.3 cm mark
- OR Repeat the experiment more than once, and get the average.
yea makes sense
ok...Thanks
Post by: aoas on May 10, 2010, 03:14:59 pm
question 3 b please
O/N 2002 p6
Ans. to Q3 "B" P6 NOV 2002
1)Reset the clock to zero.
2)Remove the 50g brass from the boiling water by one hand and press the clock to start with the other hand.
3)After a certain period of time, place the brass into the cold water while pressing the clock to stop with the other hand to find the recorded time.
Post by: aoas on May 10, 2010, 03:17:02 pm
CAN SOMEONE PLEASE WRITE ME ALL THE SUBJECTS I SHOULD STUDY FOR PAPER 6 FOR PHYSICS
THXX
Post by: Adzel on May 10, 2010, 03:17:21 pm
Anyone?
Post by: haris94 on May 10, 2010, 03:19:46 pm
Ans. to Q3 "B" P6 NOV 2002
1)Reset the clock to zero.
2)Remove the 50g brass from the boiling water by one hand and press the clock to start with the other hand.
3)After a certain period of time, place the brass into the cold water while pressing the clock to stop with the other hand to find the recorded time.
umm i think u r looking at the wrong paper
cause that does not relate to my question at all
Post by: thenewkid™ on May 10, 2010, 03:20:03 pm
Post by: Adzel on May 10, 2010, 03:21:20 pm
Post by: haris94 on May 10, 2010, 03:21:37 pm
Post by: Vin on May 10, 2010, 03:21:43 pm
Can you draw both diagrams please...
Anyone?
Post by: Shazizzzle on May 10, 2010, 03:21:53 pm
Ans. to Q3 "B" P6 NOV 2002
1)Reset the clock to zero.
2)Remove the 50g brass from the boiling water by one hand and press the clock to start with the other hand.
3)After a certain period of time, place the brass into the cold water while pressing the clock to stop with the other hand to find the recorded time.
The correct answer is to use 50.3 cm mark as the centre, i.e move the pivot to the 50.3 cm mark.
Or, use polystyrene to add to the end to balance it at 50.0 cm exactly.
Post by: Adzel on May 10, 2010, 03:23:09 pm
Post by: haris94 on May 10, 2010, 03:23:26 pm
The correct answer is to use 50.3 cm mark as the centre, i.e move the pivot to the 50.3 cm mark.
Or, use polystyrene to add to the end to balance it at 50.0 cm exactly.
yea i know but i think he has mistaken the paper
Thanks By the way
Post by: aoas on May 10, 2010, 03:24:01 pm
umm i think u r looking at the wrong paper
cause that does not relate to my question at all
oh yeah that's right ..
i answered paper 6 nov 2000 question 3 b
Post by: thenewkid™ on May 10, 2010, 03:25:34 pm
Quote
URGENT !!
CAN SOMEONE PLEASE WRITE ME ALL THE SUBJECTS I SHOULD STUDY FOR PAPER 6 FOR PHYSICS
THXX
they'll mostly ask you to measure stuff, electricity and circuit diagrams refraction reflection etc of light temperature
Post by: polltery on May 10, 2010, 03:25:54 pm
Post by: rahuldevnani93 on May 10, 2010, 03:26:32 pm
Guys this paper is May/ June 2009 and the question 5 b) is hitting my head.
The answer in the markscheme is :-
- Readings taken at either side/diameter of cylinder
- Position of mid point found
- Mark position of centre
Please give me this answer in a diagram if possible !
thank you
Post by: haris94 on May 10, 2010, 03:27:01 pm
oh yeah that's right ..
i answered paper 6 nov 2000 question 3 b
lol no probs
Thanks By the way
Post by: Adzel on May 10, 2010, 03:27:39 pm
By the way can you explain for me a bit more please (second part)
Post by: Shazizzzle on May 10, 2010, 03:29:50 pm
Can someone tell how will the diagram look like?.? ???
Post by: thenewkid™ on May 10, 2010, 03:30:52 pm
Quote
Can someone tell how will the diagram look like?.?
Post by: Malak on May 10, 2010, 03:31:33 pm
http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_6.pdf)
Thanks in advance
Post by: Adzel on May 10, 2010, 03:34:02 pm
http://www.xtremepapers.net/CIE/Cambridge%20IGCSE/0625%20-%20Physics/0625_s09_qp_6.pdf
Guys this paper is May/ June 2009 and the question 5 b) is hitting my head.
The answer in the markscheme is :-
- Readings taken at either side/diameter of cylinder
- Position of mid point found
- Mark position of centre
Please give me this answer in a diagram if possible !
thank you
Here ya' go;
Post by: rahuldevnani93 on May 10, 2010, 03:36:18 pm
Post by: thenewkid™ on May 10, 2010, 03:37:19 pm
Thanks
Post by: rahuldevnani93 on May 10, 2010, 03:37:29 pm
The answer in the markscheme is :-
- Readings taken at either side/diameter of cylinder
- Position of mid point found
- Mark position of centre
Post by: Shazizzzle on May 10, 2010, 03:37:36 pm
Question 3 part c ii and iii
http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_6.pdf)
Thanks in advance
using the graph you've made, you take the corresponding values of the time taken, at 20 deg. c, and at 30 deg. C, from the graph, and you take their ratio.
I.e., draw a dotted line from 20 deg c, where the line meets the curve, continue on to the y axis and use the value you get.
Simple division.
You will see the ratio of 20/30 and 40/50 is increasing by a set interval.
use that interval to predict the answer of 50/60.
Post by: xMilishax on May 10, 2010, 03:38:13 pm
Question 3 part c ii and iii
http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_6.pdf)
Thanks in advance
c)i)As the temperature of the water is increased, the time taken to dissolve the sugar is decreased.
c)ii)=450/160 = 45:16, =70/24 = 35:12
Hope this helps. :)
Post by: Shazizzzle on May 10, 2010, 03:39:46 pm
Because the marking scheme says it different :(
The answer in the markscheme is :-
- Readings taken at either side/diameter of cylinder
- Position of mid point found
- Mark position of centre
The marking scheme is correct.
Okay, suppose the diameter of the cylinder is 2 cm.
Mark the center of the cylinder.
Place the cylinder at 10.0 cm.
If it's diameter was 2 cm, you should be able to see exactly to the left of the cylinder, 9 cm, and to the right, 11 cm. This will prove that the centre is indeed on 10.
Post by: Adzel on May 10, 2010, 03:40:13 pm
Question 3 part c ii and iii
http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_6.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_6.pdf)
Thanks in advance
According to my graph;
(ii) 450
----- = 2.81
160
(iii)
70
---- = 2.92
24
Post by: polltery on May 10, 2010, 03:41:10 pm
Post by: red_911 on May 10, 2010, 03:41:56 pm
and
also in june 2005 question 4(c) ask about T being proptional to m .. but the mark scheme says that the answer is "NO" as T/m increases as m decreases ..why do we have to take T/m ??? ???
Post by: rahuldevnani93 on May 10, 2010, 03:42:54 pm
The marking scheme is correct.
Okay, suppose the diameter of the cylinder is 2 cm.
Mark the center of the cylinder.
Place the cylinder at 10.0 cm.
If it's diameter was 2 cm, you should be able to see exactly to the left of the cylinder, 9 cm, and to the right, 11 cm. This will prove that the centre is indeed on 10.
HEyy Shazizzzle, Please if possible draw a diagram !! please...
Post by: Malak on May 10, 2010, 03:43:09 pm
Post by: holtadit on May 10, 2010, 03:43:47 pm
how do u find the gradient by the triangle method?
Thanks
Divide the change in Y value by the change in x value
Post by: Shazizzzle on May 10, 2010, 03:44:15 pm
Wat about the iii part...predicting the value...?
The ratio is to remain the same in all.
It'll also be 2.5-ish or around.
Same as the upper two values.
Post by: Malak on May 10, 2010, 03:44:51 pm
using the graph you've made, you take the corresponding values of the time taken, at 20 deg. c, and at 30 deg. C, from the graph, and you take their ratio.
I.e., draw a dotted line from 20 deg c, where the line meets the curve, continue on to the y axis and use the value you get.
Simple division.
You will see the ratio of 20/30 and 40/50 is increasing by a set interval.
use that interval to predict the answer of 50/60.
Oh get it :D Thanks
Post by: 6394 on May 10, 2010, 03:47:14 pm
some 1 plz telme this: wen dey ask ask us to draw graph wid x axis startin frm 0.1 n y axis startin from 10 den do we have 2 put dese zigzag thingy ???????????
Post by: Shazizzzle on May 10, 2010, 03:47:28 pm
Divide the change in Y value by the change in x value
That is, draw the traingle.
then use two points A & B.
And apply the same formula!
Post by: 6394 on May 10, 2010, 03:48:09 pm
Post by: Shazizzzle on May 10, 2010, 03:48:55 pm
@ adzel wat do u do aftr placing the pin horizontly on 10 cm on the scale n
some 1 plz telme this: wen dey ask ask us to draw graph wid x axis startin frm 0.1 n y axis startin from 10 den do we have 2 put dese zigzag thingy ???????????
That zig zag thing is called a 'break'.
It is NOT required for physics.
Only in maths.
As they've made the grid already.
Post by: Adzel on May 10, 2010, 03:49:56 pm
Because the marking scheme says it different :(
The answer in the markscheme is :-
- Readings taken at either side/diameter of cylinder
- Position of mid point found
- Mark position of centre
This is correct then;
Post by: red_911 on May 10, 2010, 03:53:51 pm
hey please help me in june 2007 question 3(b)1 .. how is R propotional to 1/d square ?plzz any1 answer my questions :-\ :-\ :-\ :-\ :-\ ??? ??? ???
and
also in june 2005 question 4(c) ask about T being proptional to m .. but the mark scheme says that the answer is "NO" as T/m increases as m decreases ..why do we have to take T/m ??? ???
Post by: Shazizzzle on May 10, 2010, 03:56:40 pm
plzz any1 answer my questions :-\ :-\ :-\ :-\ :-\ ??? ??? ???
The resistance of AB is 7.92.
Of CD: 1.98.
Now, the diameter of CD TWICE of AB.
however, the resistance is not HALF of AB. The resistance is ONE FOURTH i.e ONE QUARTER of Ab.
If it were half of AB, then it would be proportional to 1/d.
as it is ONE FOURTH, it is proportional to 1/d^2.
Post by: 6394 on May 10, 2010, 03:59:44 pm
loadz Thanks
Post by: 6394 on May 10, 2010, 04:00:33 pm
:P
Post by: red_911 on May 10, 2010, 04:01:44 pm
The resistance of AB is 7.92.thanks alot ;D ;D ... do u know asnwer to my other question ?
Of CD: 1.98.
Now, the diameter of CD TWICE of AB.
however, the resistance is not HALF of AB. The resistance is ONE FOURTH i.e ONE QUARTER of Ab.
If it were half of AB, then it would be proportional to 1/d.
as it is ONE FOURTH, it is proportional to 1/d^2.
Post by: Shazizzzle on May 10, 2010, 04:02:31 pm
plzz any1 answer my questions :-\ :-\ :-\ :-\ :-\ ??? ??? ???
Although T is dropping as M does, the interval between the consecutive Ts are not the same.
To be proportional, there needs to be drop by a constant value, K. A set interval.
here, however, it first shows a deep drop from 0.9 to 0.78. Then 0.73 a short drop to 0.63.
the intervals have to be a fixed ratio.
True, I'm confused of why the mark scheme mentioned T/m. :S
Oh yes. To be directly proportional... the ratio also has to be increasing.
i.e T/m should also increase as m does. I think. :S
Post by: Mathewness on May 10, 2010, 04:03:48 pm
Question 2, (c)
How do you do that?
Post by: red_911 on May 10, 2010, 04:07:30 pm
November 2005 Paper 6
Question 2, (c)
How do you do that?
4+1.978=5.978 aprox. 6 .... resistance of wire ab and ac is added ... :)
Post by: big mac on May 10, 2010, 04:08:51 pm
1) May/June 2006 = Question 3:
http://www.freeexampapers.us/IGCSE/Physics/CIE/2006%20Jun/0625_s06_qp_6.pdf
You don't need to give me accurate measurements when they ask, just draw the thing.
Here is the same kind of thing:
2) http://www.freeexampapers.us/IGCSE/Physics/CIE/2006%20Jun/0625_s06_qp_6.pdf
Question 4.
I prefer you do the second one, it's more complicated, you can draw the diagram on paint, thank you!!
Post by: Baladya on May 10, 2010, 04:10:47 pm
To which pole does the plotting compass's arrow point?
I also can't manage to understand diff between a potential divider and potentiometer. With pics plz :)
Who wants a cookie 8) 8)?
Post by: red_911 on May 10, 2010, 04:10:55 pm
Although T is dropping as M does, the interval between the consecutive Ts are not the same.to be directly propotional the ratio has to be increasing or decreasing in a ratio ...anywayz thanks .. lets hope that someone else helps us on june 2005 question 4(c) :o
To be proportional, there needs to be drop by a constant value, K. A set interval.
here, however, it first shows a deep drop from 0.9 to 0.78. Then 0.73 a short drop to 0.63.
the intervals have to be a fixed ratio.
True, I'm confused of why the mark scheme mentioned T/m. :S
Oh yes. To be directly proportional... the ratio also has to be increasing.
i.e T/m should also increase as m does. I think. :S
Post by: xMilishax on May 10, 2010, 04:11:30 pm
Thanks in advance. :)
Post by: Baladya on May 10, 2010, 04:13:23 pm
This question has been killing me for a while, I really suck when it comes to this stuff.
1) May/June 2006 = Question 3:
http://www.freeexampapers.us/IGCSE/Physics/CIE/2006%20Jun/0625_s06_qp_6.pdf
You don't need to give me accurate measurements when they ask, just draw the thing.
Here is the same kind of thing:
2) http://www.freeexampapers.us/IGCSE/Physics/CIE/2006%20Jun/0625_s06_qp_6.pdf
Question 4.
I prefer you do the second one, it's more complicated, you can draw the diagram on paint, thank you!!
For the second one... do u mean question 5? cuz 4 doesnt have a question of drawing
Post by: Airhead on May 10, 2010, 04:13:52 pm
I also can't manage to understand diff between a potential divider and potentiometer.
I think they're pretty much the same thing. The only difference is that the potentiometer is an application of a potential divider :)
Post by: xMilishax on May 10, 2010, 04:14:04 pm
A cookie for the one who answers my questions ;D
To which pole does the plotting compass's arrow point?
I also can't manage to understand diff between a potential divider and potentiometer. With pics plz :)
Who wants a cookie 8) 8)?
It points towards north pole.
Post by: big mac on May 10, 2010, 04:17:31 pm
For the second one... do u mean question 5? cuz 4 doesnt have a question of drawing
yeah yeah sorry lol.
Post by: Vin on May 10, 2010, 04:18:21 pm
This question has been killing me for a while, I really suck when it comes to this stuff.
1) May/June 2006 = Question 3:
http://www.freeexampapers.us/IGCSE/Physics/CIE/2006%20Jun/0625_s06_qp_6.pdf
You don't need to give me accurate measurements when they ask, just draw the thing.
here .. :)
Post by: Baladya on May 10, 2010, 04:18:39 pm
How do you use a screw gauge? Can anybody please explain.
Thanks in advance. :)
Make sure it closes completely and the scale is 0 when its closed. Open the jaws, and put the object, close it. A scale on the barrel (scale next to jaw) shows the thickness in millimeters. Lets say the object has a thickness of 5.82. The scale on the barrel will show 5.5 and a lil bit. To know this lil bit, u have another scale on the thimble (the one next to barrel) this will tell u to add a certain amount to the 5.5. In this case it will show 0.32. U already have 5.5, now just add 0.38 to it and u will have 5.82
If u dont understand tell me...
Post by: Mathewness on May 10, 2010, 04:19:06 pm
4+1.978=5.978 aprox. 6 .... resistance of wire ab and ac is added ... :)
Thanks man.
General question about resistance wires; what are they exactly? And how would we draw them in a circuit?
For example how would we draw two resistance wires?
Post by: Shazizzzle on May 10, 2010, 04:19:55 pm
I think they're pretty much the same thing. The only difference is that the potentiometer is an application of a potential divider :)
A potential divider is when you have two resistors in a circuit, and the one with the higher resistance, has the higher p.d across it.
A potentiometer is a component yo use, usually like a rheostat, with a slider across a resistor, that varies the p.d across what's connecter to the slider. i.e full voltage, no resistance.
Full resistance, no voltage.
Post by: red_911 on May 10, 2010, 04:20:20 pm
here .. :)its wrong ..see the question again ... the line IJ should be inside the block
Post by: red_911 on May 10, 2010, 04:21:58 pm
Thanks man.draw a wire and a resistor on it ,,, i mean a rectangular block ( the symbol of a resistor) ;D ;D
General question about resistance wires; what are they exactly? And how would we draw them in a circuit?
For example how would we draw two resistance wires?
Post by: Baladya on May 10, 2010, 04:22:24 pm
yeah yeah sorry lol.
Here u go :D
Post by: xMilishax on May 10, 2010, 04:23:10 pm
Make sure it closes completely and the scale is 0 when its closed. Open the jaws, and put the object, close it. A scale on the barrel (scale next to jaw) shows the thickness in millimeters. Lets say the object has a thickness of 5.82. The scale on the barrel will show 5.5 and a lil bit. To know this lil bit, u have another scale on the thimble (the one next to barrel) this will tell u to add a certain amount to the 5.5. In this case it will show 0.32. U already have 5.5, now just add 0.38 to it and u will have 5.82
If u dont understand tell me...
Thank you. :)
Post by: Shazizzzle on May 10, 2010, 04:23:47 pm
here .. :)
Shouldn't JI be INSIDE the block? :S :S
That's how I got it.
Post by: Baladya on May 10, 2010, 04:24:08 pm
A potential divider is when you have two resistors in a circuit, and the one with the higher resistance, has the higher p.d across it.Thanks man ;)
A potentiometer is a component yo use, usually like a rheostat, with a slider across a resistor, that varies the p.d across what's connecter to the slider. i.e full voltage, no resistance.
Full resistance, no voltage.
Post by: wstrawberries on May 10, 2010, 04:24:28 pm
Thank you so much for your help.
Post by: Vin on May 10, 2010, 04:24:53 pm
Here u go :D
gud one +rep .. :)
Post by: Baladya on May 10, 2010, 04:26:20 pm
It points towards north pole.Hey guys is this right? cuz i thought it showed where the field lines are going by pointing towards the south (field lines going in S) and pointing away from North (field lines going out of N)?? Or is he correct?
Post by: Baladya on May 10, 2010, 04:27:07 pm
gud one +rep .. :)
Hahaha I dont need ur sh*t man...
Nah just kidding xD Appreciated :D
Post by: Mathewness on May 10, 2010, 04:27:48 pm
draw a wire and a resistor on it ,,, i mean a rectangular block ( the symbol of a resistor) ;D ;D
So how would you draw the circuit in question 2 (a) paper 6 november 08?
Post by: helpmekthanks on May 10, 2010, 04:29:55 pm
Post by: Airhead on May 10, 2010, 04:30:19 pm
Hey guys is this right? cuz i thought it showed where the field lines are going by pointing towards the south (field lines going in S) and pointing away from North (field lines going out of N)?? Or is he correct?
Yeah - a compass always points towards the Magnetic North Pole of the Earth :l
Post by: Shazizzzle on May 10, 2010, 04:31:40 pm
In october november 2001, on pg 9..There is a question about temperature change. How do we determine which can reached its final temperature first and the initial temperature of water?
Thank you so much for your help.
The one that smoothened out earlier was the one that reached it's final temp most early. i.e R.
You continue all the three curves backwards, roughly. They meet at a point. That point is the initial room temperature. :P
Post by: Shazizzzle on May 10, 2010, 04:33:26 pm
How do i make sure electrodes are the same length apart after i take them out of the water to measure? that questions been KILLING me.. :D.
You don't say how. :P You just say you have to. :p
But...
I guess you can use some wool, or rectangular block in between while taking 'em out.
or use a tong to pull 'em out? :S i.e a clipper.
Post by: TheLonelyIsland on May 10, 2010, 04:37:15 pm
Thx, good luck to everyone! ;)
Post by: polltery on May 10, 2010, 04:39:24 pm
Post by: Mathewness on May 10, 2010, 04:46:39 pm
Can someone help me wid Q B givin in the following img.! .. (give ur Ans, diagram and explanation if possible)
Yes, Id like an answer + explanation for this as well
Post by: Vin on May 10, 2010, 04:49:44 pm
Hi, can someone plz answer the whole of q4, oct/nov 2009, p6... I just can`t wrap my mind around the readings, I always get a different one... It`s the focal length, that they just tell you to measure, the diameter and the thickness... I don`t get it, but I think that`s clear by now :P
Thx, good luck to everyone! ;)
See it depends on ur print out .. the printout size may vary with the ms .. it might not be the pdf size .. :)
Post by: Vin on May 10, 2010, 04:52:14 pm
CHECK THE PREVIOUS POSTS .. IM TIRED SOLVING THIS QUES 50th TIME .. !!
Post by: Baladya on May 10, 2010, 04:54:03 pm
Yeah - a compass always points towards the Magnetic North Pole of the Earth :lThanks :D
woooohohoh VIN, chill man xD ;D
poor guy is frustrated from exams xD
Post by: aoas on May 10, 2010, 04:54:17 pm
for part (a) : a diagram please
and part (b)
thxx
Post by: Mathewness on May 10, 2010, 04:58:03 pm
CHECK THE PREVIOUS POSTS .. IM TIRED SOLVING THIS QUES 50th TIME .. !!
Which question are you talking about?
Post by: Vin on May 10, 2010, 05:00:03 pm
here .. ;)
Post by: Vin on May 10, 2010, 05:00:58 pm
Yes, Id like an answer + explanation for this as well
Post by: Mathewness on May 10, 2010, 05:02:15 pm
here .. ;)
Oh, thanks. This is correct yea? ;D
Post by: PeaceMaker on May 10, 2010, 05:03:48 pm
Post by: Baladya on May 10, 2010, 05:04:09 pm
V and A
and part (b)
thxx
Post by: Vin on May 10, 2010, 05:06:00 pm
Oh, thanks. This is correct yea? ;D
It should be .. because 50 ppl. hav already watched this before .. :)
Post by: Mathewness on May 10, 2010, 05:07:05 pm
It should be .. because 50 ppl. hav already watched this before .. :)
Thanks dude. :D Repped.
Post by: Baladya on May 10, 2010, 05:07:29 pm
Q5 2009, may/june. Would be greatful if someone could solve it for me or tell me how to solve it because if such a question came, id be able to solve it.My friend asked me about this today and i was clueless :P
By the way Vin xD hehehehee ;D
Post by: Vin on May 10, 2010, 05:11:12 pm
Q5 2009, may/june. Would be greatful if someone could solve it for me or tell me how to solve it because if such a question came, id be able to solve it.
working on it .. it'll tak some time .. :)
Post by: Airhead on May 10, 2010, 05:14:25 pm
working on it .. it'll tak some time .. :)
Part b is a little weird - I tried something but I don't think it's right :l
Post by: Shazizzzle on May 10, 2010, 05:14:42 pm
It's just a Paper 6.
Chillax guys, will you. :) :P XD
Post by: xMilishax on May 10, 2010, 05:20:42 pm
Part b is a little weird - I tried something but I don't think it's right :l
Yeah, I don't get that part either. :-\
Post by: Adzel on May 10, 2010, 05:24:50 pm
Q5 2009, may/june. Would be greatful if someone could solve it for me or tell me how to solve it because if such a question came, id be able to solve it.
My attempt;
Post by: NightHawkerr on May 10, 2010, 05:28:21 pm
Okay so I've been solving past papers, and you know the questions about the measuring x or h or whatever, well I measured that with my ruler, and when i checked in the marking scheme, it used to have an answer near to that but never the same. So will i be penalized in tomorrow's exam? Also the marking scheme doesnt really mention the uncertainties. And every past paper has a question which asks us to measure the length of a line. :/ :-[
Post by: Mathewness on May 10, 2010, 05:31:45 pm
Umm. Hey guys!
Okay so I've been solving past papers, and you know the questions about the measuring x or h or whatever, well I measured that with my ruler, and when i checked in the marking scheme, it used to have an answer near to that but never the same. So will i be penalized in tomorrow's exam? Also the marking scheme doesnt really mention the uncertainties. And every past paper has a question which asks us to measure the length of a line. :/ :-[
Don't worry about that, it's just when you print them out they get resized.
In the real thing they dont get resized.
Post by: Shazizzzle on May 10, 2010, 05:32:35 pm
In the real thing tomorrow, all booklets will be the same.
Printing or photocopying edits the size. Not to worry. :)
Post by: Vin on May 10, 2010, 05:32:36 pm
Post by: xMilishax on May 10, 2010, 05:34:24 pm
Umm. Hey guys!
Okay so I've been solving past papers, and you know the questions about the measuring x or h or whatever, well I measured that with my ruler, and when i checked in the marking scheme, it used to have an answer near to that but never the same. So will i be penalized in tomorrow's exam? Also the marking scheme doesnt really mention the uncertainties. And every past paper has a question which asks us to measure the length of a line. :/ :-[
Hey, this has been asked a lot of times here already. As you aren't solving the original paper differences in readings occur and that's why you are getting a slightly different answers! This will not be the case in the exam tomorrow as each student will have the original copy. Plus, I don't think they penalise for small differences so don't worry. :)
Post by: Vin on May 10, 2010, 05:35:07 pm
My attempt;
didnt see u'd already posted .. :)
Post by: xMilishax on May 10, 2010, 05:39:09 pm
centre marked on the cylinder .. coinciding the pin below .. :) :)
Thank you. :)
Post by: Vin on May 10, 2010, 05:41:47 pm
Post by: Adzel on May 10, 2010, 05:47:35 pm
Post by: Malak on May 10, 2010, 05:50:25 pm
@ VIN : Read the question properly, it said "Load Q is placed carefully on the balenced metre rule"...It IS balanced before placing the Load Q..After u plave the load the rule gets tilted :)
Post by: Fastal on May 10, 2010, 05:51:00 pm
@ VIN : Read the question properly, it said "Load Q is placed carefully on the balenced metre rule"...
it says rule correctly tilted in markscheme
the rule is still balanced.
Post by: polltery on May 10, 2010, 05:51:23 pm
Post by: Adzel on May 10, 2010, 05:52:37 pm
Post by: thenewkid™ on May 10, 2010, 05:53:53 pm
Post by: Fastal on May 10, 2010, 05:54:09 pm
can someone show me how will this look like?... i have made it but still .. i want to clarify my ans! .. Thanks!
here:)
double click black box to see
Post by: Vin on May 10, 2010, 05:54:59 pm
that it covers the markings on the rule. Load Q is placed carefully on the balanced metre rule
with its centre at the 84.2 cm mark. The rule does not slip on the pivot.
YOU read the question properly .. :P :D :D dude jus kiddin' it happens :)
Post by: Adzel on May 10, 2010, 05:55:35 pm
good luck 2 everyone 4 2morrows exam. may Allah help us all
InshAllah :)
Post by: NightHawkerr on May 10, 2010, 05:56:01 pm
Thanks alot. :)
By the way in May/June 2004, Q4b) ,
Why is the image upside down?
Post by: Shazizzzle on May 10, 2010, 05:58:09 pm
What a relief :D
Thanks alot. :)
By the way in May/June 2004, Q4b) ,
Why is the image upside down?
It's a convex lens.
When the object is NOT within the focal length of the lens, it is inverted, ALWAYS. :)
Also, is the image we draw supposed to be 5 times magnified too?
Post by: Shazizzzle on May 10, 2010, 06:00:29 pm
InshAllah, it'll be easy, and will go awesome for everyone. InshAllah!
Best of luck! :)
Post by: Baladya on May 10, 2010, 06:02:19 pm
This is what my book says... but how come the electrons go down (srry for bad quality). If u use Flemingooo's left hand rule, the current is ur middle finger(so points to the left [direction of electrons]), the field is ur second finger (pointing into the paper[direction of magnetic field]) and so ur thumb will be pointing up, which shows how the electrons will be deflected...How come they show it going down?
Post by: NightHawkerr on May 10, 2010, 06:05:03 pm
It's a convex lens.
When the object is NOT within the focal length of the lens, it is inverted, ALWAYS. :)
Also, is the image we draw supposed to be 5 times magnified too?
So how do we know where's the focal length in the diagram?
Yeah the ms says it'll be upside down, and i think it'll also be magnified since the magnification is 5.2
Post by: The Golden Girl =D on May 10, 2010, 06:08:35 pm
hope i helped
gd luck people of da universe ..allah yiwafi8na jamee3an , AMEEN!!
Post by: Malak on May 10, 2010, 06:09:11 pm
So how do we know where's the focal length in the diagram?I dnt think so we hav to draw it as magnified...If that would be the case they would mention it...Atleast in MS
Yeah the ms says it'll be upside down, and i think it'll also be magnified since the magnification is 5.2
Post by: Shazizzzle on May 10, 2010, 06:09:59 pm
So how do we know where's the focal length in the diagram?
Yeah the ms says it'll be upside down, and i think it'll also be magnified since the magnification is 5.2
Well, they say the image forms on the screen.
If it were within the focal length, the upright image would be virtual thus impossible to project.
So, the only image projectable, is an upside down one. :)
Post by: Adzel on May 10, 2010, 06:11:25 pm
OK then....By the way what's a set square
Post by: NightHawkerr on May 10, 2010, 06:12:58 pm
Well, they say the image forms on the screen.
If it were within the focal length, the upright image would be virtual thus impossible to project.
So, the only image projectable, is an upside down one. :)
owh okay, i get it. Thanks alot :)
Post by: Malak on May 10, 2010, 06:16:26 pm
Its a rule which u use to check if an object is Perpendicular or wtte :P
(http://img535.imageshack.us/img535/5776/91370952.jpg)
Post by: Adzel on May 10, 2010, 06:20:54 pm
Post by: Hesham Mhd on May 10, 2010, 06:22:15 pm
Post by: Baladya on May 10, 2010, 06:23:02 pm
"An electron beam is equivilent to an electric current, but without the wire. It can bla bla bla.... In this diagram, the magnetic field is at right angles to the electron beam, so the beam is deflected."
This is what my book says... but how come the electrons go down (srry for bad quality). If u use Flemingooo's left hand rule, the current is ur middle finger(so points to the left [direction of electrons]), the field is ur second finger (pointing into the paper[direction of magnetic field]) and so ur thumb will be pointing up, which shows how the electrons will be deflected...How come they show it going down?
Cmon guys helpsss :D
Thanks ;)
Post by: Malak on May 10, 2010, 06:25:31 pm
Explain more with an aid of a diagram please...Umm...For example...Here to make sure that the rule correctly positioned
http://img3.imageshack.us/img3/8131/76681659.png (http://img3.imageshack.us/img3/8131/76681659.png)
U get it??
Post by: Adzel on May 10, 2010, 06:27:52 pm
Post by: Shazizzzle on May 10, 2010, 06:28:45 pm
What is the main question? :S
Why the glass stopper was heated?
Why it was heated for a long time?
Or, why was it heated in boiling WATER?
I mean, where does the emphasis lie?
If they meant long time, then obviously so that evenly and completely, the glass stopper fully reaches 100 deg. C, i.e as it has a hight sp. ht. capacity and may take longer.
If, why specifically in boiling WATER and not directly, well because, the glass would crack on direct contact with the heater.
What exactly is the ans? MS, anyone?
Also, the same question, part (e), is the answer:
This is because it has a greater size and thus greater mass comparatively, and thus has a higher thermal capacity and so will gain more internal energy, and transfer more of it to the water as compared to the smaller one.
That is the answer I wrote. Kindly correct! :)
Post by: Ivo on May 10, 2010, 06:30:42 pm
on 0625/05/O/N/09 Q.2 iv) Where I have to record the temp. readings, in the mark scheme it says temperatures decreasing - does that mean I won't get the mark if one of them is the same e.g. 85, 84, 83, 83, 81, 81, 80, 79. Therefore, does it mean all the temp. readings have to be decreasing, and so I won't get the mark in the example above?
Also, for the last marking point for that question, where it says "evidence of temperatrues to 1 degrees" does that mean I shouldn't right 37.5 degrees?
Here are the links to the papers and MS:
http://www.xtremepapers.net/CIE/Cambridge%20IGCSE/0625%20-%20Physics/0625_w09_qp_5.pdf (http://www.xtremepapers.net/CIE/Cambridge%20IGCSE/0625%20-%20Physics/0625_w09_qp_5.pdf)
http://www.xtremepapers.net/CIE/Cambridge%20IGCSE/0625%20-%20Physics/0625_w09_ms_5.pdf (http://www.xtremepapers.net/CIE/Cambridge%20IGCSE/0625%20-%20Physics/0625_w09_ms_5.pdf)
Many thanks in advance!
Post by: Shazizzzle on May 10, 2010, 06:47:13 pm
I helped so many of you! :O
ANSWER my post, Please! :P
Post by: TheLonelyIsland on May 10, 2010, 07:13:02 pm
Thx!! ;)
Post by: Shazizzzle on May 10, 2010, 07:17:46 pm
I.e, either at the bottom, or at the top, but in parallel to the whole thing, for all three lamps.
| |
|_ _ (X) _ _ |
| |
|_ _ (X) _ _ |
| |
|_ _ (X) _ _ |
| |
|_ _ (V) _ _ |
Post by: TheLonelyIsland on May 10, 2010, 07:27:05 pm
Post by: princess12 on May 10, 2010, 07:30:24 pm
Post by: Malak on May 10, 2010, 07:33:25 pm
what we should take wiyh us for exam of physics ??? ???As in equipment / stationery??
Post by: MasterMath on May 10, 2010, 07:42:17 pm
should you draw the rule and the cylinder and mark the center of the cylinder AND THEN DRAW ANOTHER Rule under it to measure the distance or the diagram without extra ruler is enough?
Post by: xMilishax on May 10, 2010, 07:43:03 pm
Umm, in May/June 2001, Q4, part (b),
What is the main question? :S
Why the glass stopper was heated?
Why it was heated for a long time?
Or, why was it heated in boiling WATER?
Also, the same question, part (e), is the answer:
This is because it has a greater size and thus greater mass comparatively, and thus has a higher thermal capacity and so will gain more internal energy, and transfer more of it to the water as compared to the smaller one.
That is the answer I wrote. Kindly correct! :)
The answer I wrote to part b) is - To make sure that the glass stopper reaches about 100 degree celcius.
And you are absolutely correct with your part e) answer! Heat capacity of the larger glass stopper is more so greater heat energy is transferred. :)
Thanks for all your hard work. ;D
Good luck!
Post by: xMilishax on May 10, 2010, 07:44:33 pm
I have one question.. you guys know for the questions where they tell you the cylinder placed on the rule covers the mark..
should you draw the rule and the cylinder and mark the center of the cylinder AND THEN DRAW ANOTHER Rule under it to measure the distance or the diagram without extra ruler is enough?
This has already been done. Please check previous posts! :)
Post by: diva_sparkles on May 10, 2010, 08:05:53 pm
Umm, in May/June 2001, Q4, part (b),
What is the main question? :S
Why the glass stopper was heated?
Why it was heated for a long time?
Or, why was it heated in boiling WATER?
I mean, where does the emphasis lie?
If they meant long time, then obviously so that evenly and completely, the glass stopper fully reaches 100 deg. C, i.e as it has a hight sp. ht. capacity and may take longer.
If, why specifically in boiling WATER and not directly, well because, the glass would crack on direct contact with the heater.
What exactly is the ans? MS, anyone?
Also, the same question, part (e), is the answer:
This is because it has a greater size and thus greater mass comparatively, and thus has a higher thermal capacity and so will gain more internal energy, and transfer more of it to the water as compared to the smaller one.
That is the answer I wrote. Kindly correct! :)
Post by: PeaceMaker on May 10, 2010, 08:07:31 pm
Post by: Shazizzzle on May 10, 2010, 08:08:23 pm
Thank you. :)
Post by: DCS guy on May 10, 2010, 08:32:57 pm
Q4 b
what should i draw after the triangle?
can someone show me.... ;D
Post by: Malak on May 10, 2010, 08:34:09 pm
p6/MJ/2004Thats the only thing ur supposed to draw..
Q4 b
what should i draw after the triangle?
can someone show me.... ;D
Post by: DCS guy on May 10, 2010, 08:37:09 pm
Thats the only thing ur supposed to draw..
oh! ok!
thx
Post by: Malak on May 10, 2010, 08:37:44 pm
oh! ok!nytime :)
thx
Post by: helpmekthanks on May 10, 2010, 08:43:22 pm
Thanks :)
http://www.freeexampapers.us/IGCSE/Physics/CIE/2006%20Nov/0625_w06_qp_6.pdf
Post by: Malak on May 10, 2010, 08:53:59 pm
November 2006 3) b) ii)
Thanks :)
http://www.freeexampapers.us/IGCSE/Physics/CIE/2006%20Nov/0625_w06_qp_6.pdf
http://img714.imageshack.us/img714/8662/62783363.png (http://img714.imageshack.us/img714/8662/62783363.png)
Post by: DCS guy on May 10, 2010, 09:18:04 pm
Q4 (a)
where do i draw the pins?
Post by: DCS guy on May 10, 2010, 09:18:44 pm
ON 2004
:o
Post by: Shazizzzle on May 10, 2010, 09:19:00 pm
Laters! :)
Take care! AH!
And
BEST OF LUCK FOR TOMORROW! :)
be confident. InshAllah, it'll be easy! (=
Post by: DCS guy on May 10, 2010, 09:19:38 pm
Right, I'm off people.GOOD LUCK!!!
Laters! :)
Take care! AH!
And
BEST OF LUCK FOR TOMORROW! :)
be confident. InshAllah, it'll be easy! (=
Post by: Malak on May 10, 2010, 09:24:52 pm
srry
ON 2004
:o
http://img189.imageshack.us/img189/3418/50268355.png
here...
Post by: DCS guy on May 10, 2010, 09:26:15 pm
http://img189.imageshack.us/img189/3418/50268355.pngthx! :D
here...
Post by: Malak on May 10, 2010, 09:27:28 pm
thx! :D
Welcome :)
GoodLuck Everyone!!
Post by: big mac on May 10, 2010, 09:32:35 pm
Post by: Malak on May 10, 2010, 09:41:52 pm
Hey everyone, I'm having a lot of problems with finding the gradient of the line in the graph, I consistanly see this question in ever paper, can anyone please explain this to me in detail? I'm clueless about this, I think we have to draw a triangle or something? would be much appreciated if you show me a labelled diagram please, thanks
Draw a triangle that way for any graph
http://img96.imageshack.us/img96/7507/56248804.png
Post by: princess12 on May 10, 2010, 09:42:45 pm
Post by: Ivo on May 10, 2010, 11:47:52 pm
Post by: The Golden Girl =D on May 11, 2010, 03:21:17 am
Are the diagrams essentially the same? Sorry about the bad handwriting!
ya !!
Post by: Vin on May 11, 2010, 03:47:33 am
HEY PEOPLE GOOD LUCK .. DO WELL .. PLS. TAKE TOTAL ADVANTAGE OF THE HELP PROVIDED BY PPL IN THE PAST .. :) :)
:D do well guys .. ;)
Post by: $H00t!N& $t@r on May 11, 2010, 08:07:01 am
cnt believe its time for me to do IGs. Im really nervous!
By the way what time is your exam? My exam is at 1:30 so i still have time to revise
Post by: Fastal on May 11, 2010, 08:08:19 am
@Vin thx same to you.
cnt believe its time for me to do IGs. Im really nervous!
By the way what time is your exam? My is at 1:30 so i still have time to revise
which exam physics p6?
exams are still going n for that paper?
Post by: $H00t!N& $t@r on May 11, 2010, 08:12:48 am
Yeah do u do physics? dont you have an exam today?
which exam physics p6?
exams are still going n for that paper?
Post by: The Golden Girl =D on May 11, 2010, 08:13:53 am
which exam physics p6?
exams are still going n for that paper?
FYI the timing differs around the world hence exam timing r different too!!!
Post by: dodi23 on May 11, 2010, 08:38:36 am
its 10:30 now,,,im nervous!!! :-\ :-\
Post by: ruruiw 60984 on May 11, 2010, 08:54:14 am
may someone help me in May/June 2003 Q 4b ii) . why did we divide by 4 ??
it seems simply , i just dont know why by 4 ..
Good luck to all.. :D
Same here dodi23
Post by: holtadit on May 11, 2010, 08:57:36 am
im doing physics p6 at 3 in ksa!!!!
its 10:30 now,,,im nervous!!! :-\ :-\
Its one of the easiest Paper 6’s ever. I just finished it.
DON’T ask me any questions about whats coming as that would be against the rules.
Post by: Fastal on May 11, 2010, 09:05:01 am
Post by: Adzel on May 11, 2010, 09:15:58 am
Post by: $H00t!N& $t@r on May 11, 2010, 09:29:44 am
Good luck every1 for the physics exam and the ones after this!
Post by: Vin on May 11, 2010, 09:32:24 am
"An electron beam is equivilent to an electric current, but without the wire. It can bla bla bla.... In this diagram, the magnetic field is at right angles to the electron beam, so the beam is deflected."
This is what my book says... but how come the electrons go down (srry for bad quality). If u use Flemingooo's left hand rule, the current is ur middle finger(so points to the left [direction of electrons]), the field is ur second finger (pointing into the paper[direction of magnetic field]) and so ur thumb will be pointing up, which shows how the electrons will be deflected...How come they show it going down?
YA so it is right !! it is supposed to go down .. check again !! index finger diagonally up .. middle finger pointing left .. thumb down !!
Post by: Baladya on May 11, 2010, 09:50:28 am
YA so it is right !! it is supposed to go down .. check again !! index finger diagonally up .. middle finger pointing left .. thumb down !!
ya but in the book its going to the right... Magentic field in the paper, movement down. (its just the camera changed it). So how?
Post by: Vin on May 11, 2010, 09:59:15 am
I think they might hav considered the beam of electron as a conventional current in the opposite direction .. which book is it ..By the way ??
Post by: Ghost Of Highbury on May 11, 2010, 10:02:59 am
yes, its about the conventional current..
Post by: Baladya on May 11, 2010, 10:04:25 am
Vin its the IGCSE Collin thingy book :D
Post by: Vin on May 11, 2010, 10:13:57 am
Oh i hate collins .. dunno abt phy but i hate its chemistry .. can u believe its thinner thn my notebook !!
Post by: astarmathsandphysics on May 11, 2010, 10:16:07 am
Post by: Baladya on May 11, 2010, 11:03:36 am
Oh i hate collins .. dunno abt phy but i hate its chemistry .. can u believe its thinner thn my notebook !!
It has nothing in it...
Post by: Baladya on May 11, 2010, 11:06:33 am
Post by: astarmathsandphysics on May 11, 2010, 11:09:47 am
The 1/2 is cos accelerations is from rest
on a velocity time graph the distance is area under curve - a triangle so area =1/2base*height hence the 1/2
Post by: Ghost Of Highbury on May 11, 2010, 11:10:36 am
Distance =
u = inital velocity
v = final velocity
t = time
a = acceleration
u is generally -, so the formula boils down to
Distance =
1/2 = 0.5
Therefore,
Distance = 0.5at2
Post by: Vin on May 11, 2010, 11:12:02 am
Hey VIN. I asked u a question b4 and u said for accelerating objects u do this formula: 0.5ta (timeXacceleration) K but why the 0.5????????????
whoa wen did i say tht ??
Post by: Baladya on May 11, 2010, 11:13:16 am
1/2 at^2
The 1/2 is cos accelerations is from rest
on a velocity time graph the distance is area under curve - a triangle so area =1/2base*height hence the 1/2
No i want speed not distance. Cuz there was a question (cant remember what paper) and it said what is the speed. So i did: DISTANCE/TIME. However the answer was diff. and Vin told me to do 0.5at to find the SPEED. ???
Post by: Baladya on May 11, 2010, 11:14:00 am
whoa wen did i say tht ??
maybe u said o.5at^2... i dont remember what exactly :P but u said it here :D :P
Post by: dodi23 on May 11, 2010, 11:14:31 am
Post by: Vin on May 11, 2010, 11:14:58 am
v = u + at
s= 1/2 (v+u) * t
s = ut + 1/2 at2
v2 = u2 + 2as
..
Post by: Vin on May 11, 2010, 11:17:57 am
maybe u said o.5at^2... i dont remember what exactly :P but u said it here :D :P
lol i may make mistakes while solving a sum but i always remember the formula .. !! =)
Post by: Ghost Of Highbury on May 11, 2010, 11:19:15 am
Remember the formula dont get confused
v=u+at
v^2 = u^2 + 2as
S=(u+v)/2 *t
S = ut + 0.5at^2
Post by: Baladya on May 11, 2010, 11:19:41 am
baladya>>i love ur signiture :P :P
HAHAHA Do u know how many people told me that xD
Thanks VIN, Aodi, and Sir :D :D
Post by: PeaceMaker on May 11, 2010, 02:55:38 pm
Post by: Shazizzzle on May 11, 2010, 03:19:53 pm
Post by: 33oomar on May 11, 2010, 03:37:59 pm
Post by: holtadit on May 11, 2010, 03:48:00 pm
General Note :
NO DISCUSSING DETAILS OF THE EXAMINATION !
WAIT TILL 24 HOURS have PASSED
Post by: Fastal on May 11, 2010, 05:30:31 pm
in physics, do we give answers to 2dp or 3sf,
my friends were saying 2 dp is preferred as it is written in the syllabus, but i cant find it anywhere
Post by: Baladya on May 11, 2010, 06:00:39 pm
i have a major questionm too not sure of that, but i think u can give it to any of them... Also depends on the question, if it needs decimals then dont round to the nearest whole digit ;). Not sure tho :)
in physics, do we give answers to 2dp or 3sf,
my friends were saying 2 dp is preferred as it is written in the syllabus, but i cant find it anywhere
Post by: holtadit on May 11, 2010, 06:10:30 pm
i have a major question
in physics, do we give answers to 2dp or 3sf,
my friends were saying 2 dp is preferred as it is written in the syllabus, but i cant find it anywhere
You MUST choose either 2 SF or 3 SF
Post by: haris94 on May 11, 2010, 06:27:57 pm
Paper 6 was easy but confusing at some parts. But i think i messed up *sighs* i wrote some answers by pencil and forgot to write them with pen because i didn't have enough time. Will they put marks on it or not? if not then i think i'll be getting D or E in paper 6. :(
i hv heard that they do not correct anything done in pencil
but for your sake i hope im wrong
Post by: The Golden Girl =D on May 11, 2010, 09:14:20 pm
Paper 6 was easy but confusing at some parts. But i think i messed up *sighs* i wrote some answers by pencil and forgot to write them with pen because i didn't have enough time. Will they put marks on it or not? if not then i think i'll be getting D or E in paper 6. :(
be optimistic and pray cuz god helps everyone ........ " allah yijeeb da3awat ida3i so id3ei Allah ino Allah yiwaf8ak !! ...... ithi8 fi illah wa allah rah yisa3dak ;) "
Post by: The Golden Girl =D on May 11, 2010, 09:20:19 pm
Paper 6 was easy but confusing at some parts. But i think i messed up *sighs* i wrote some answers by pencil and forgot to write them with pen because i didn't have enough time. Will they put marks on it or not? if not then i think i'll be getting D or E in paper 6. :(
one of the moderators whose my friend "nid404" said the followin
I went through a tough time last year when I wrote my french listening paper in pencil...lol..but the paper was good. They were kind enough to let go of my folly, I ended up with an A* CIE can be good sometimes
" she is soo gonna kill me if she sees me postin this :P , actually she won't ::) "
Post by: Vin on May 11, 2010, 09:37:46 pm
Of course not .. shes really sweet .. :)
Post by: The Golden Girl =D on May 12, 2010, 06:53:26 am
Of course not .. shes really sweet .. :)
i kno ::) lol :P
Post by: WARRIOR on May 12, 2010, 02:21:20 pm
I did paper 6 phyics yestreday and i was wondering... the graph for the heat ..the beaker...everyone drew a cure ..but i drew a best fit...how many marks will i lose? and is a best fit graph wrong Sad i feel depressed really..i should have aced paper 6 Sad now my chanced for an A* has decreased Sad o lord Sad
By the way i posted this in the forum of all examinations of 2010..no one answrd :( im hopin some1 asnwes here thx
bttw i did first variant
Post by: Vin on May 12, 2010, 02:33:20 pm
check again i replied twice .. ;)
Post by: SEL123 on May 12, 2010, 04:39:23 pm
I finished the angles stuff at EXACTLY one hour
Then I guessed for the next two pages the answers, while the papers were being taken.
I'm going to have to do AMAZINGLY in paper 1 and 6 to get an A, because the curve for this year is going to be pretty high...
When they ask for justification USING your results
Do we have to say exactly using numbers???
Post by: SEL123 on May 12, 2010, 04:43:49 pm
Number 10 B
There's a thermistor and a transistor
b- State and explain how the circuit may be modified so that the lamp switches on at different temperatures.
The mark scheme says:
change value of R1/use variable res/swap R1 with something
brief explanation in terms of potential divider
How EXACTLY, should we change R1, or where should we use the variable resistor...And I don't get how we explain it "in terms of potential divider"
Post by: SEL123 on May 12, 2010, 05:05:41 pm
Does anyone know if there are IGs in Lebanon.?
Post by: holtadit on May 12, 2010, 05:17:41 pm
May June 2007
Number 10 B
There's a thermistor and a transistor
b- State and explain how the circuit may be modified so that the lamp switches on at different temperatures.
The mark scheme says:
change value of R1/use variable res/swap R1 with something
brief explanation in terms of potential divider
How EXACTLY, should we change R1, or where should we use the variable resistor...And I don't get how we explain it "in terms of potential divider"
There is a designated thread for these kind of dicussions here :
https://studentforums.biz/index.php/topic,7273.msg200847/boardseen.html#new
Post by: J.Darren on May 13, 2010, 07:14:23 pm
May June 2007Thermistor.
Number 10 B
There's a thermistor and a transistor
b- State and explain how the circuit may be modified so that the lamp switches on at different temperatures.
The mark scheme says:
change value of R1/use variable res/swap R1 with something
brief explanation in terms of potential divider
How EXACTLY, should we change R1, or where should we use the variable resistor...And I don't get how we explain it "in terms of potential divider"
As the temperature increases, the resistance in the thermistor decreases. It is a definiton, as thermistor is made up of semi-conductors.
The lower part of the circuit gets more share of the resistance, more current can then flow through it, thus switching on the lamp.
Post by: WARRIOR on May 19, 2010, 10:19:54 am
question 10 (c)
why do u calculat power and it says energy
Post by: Vin on May 19, 2010, 11:26:09 am
http://www.xtremepapers.net/CIE/Cambridge%20IGCSE/0625%20-%20Physics/0625_w09_qp_31.pdf
question 10 (c)
why do u calculat power and it says energy
10 a)
i) By using a Step Up Transformer
ii) less energy lost from power lines
b) I = P/V
= 55000/22000
= 2.5 A
c) It says "rate of loss of energy"
amount of heat energy transferred to heat due to the resistance of the wires is directly proportional to the square of the current so I2R
P = I2R
= 2.52 * 3
= 18.75 W
Post by: Ghost Of Highbury on May 19, 2010, 11:30:06 am
http://www.xtremepapers.net/CIE/Cambridge%20IGCSE/0625%20-%20Physics/0625_w09_qp_31.pdf
question 10 (c)
why do u calculat power and it says energy
Energy Transferred = Power * Time
Power = I^2 * R
Energy Transferred = I^2 * R * t
t = 1
I = 2.5
R = 3
18.75J..
or 18.75W per second.
Post by: WARRIOR on May 19, 2010, 12:06:37 pm
Post by: Vin on May 19, 2010, 12:10:11 pm
Energy Transferred = Power * Time
18.75J..
or 18.75W per second.
hey jus a doubt .. isnt Watt already Joule/second ??
Post by: J.Darren on May 19, 2010, 12:32:43 pm
hey jus a doubt .. isnt Watt already Joule/second ??Yes, as Watt = Work done (J) / Time (s)
Post by: WARRIOR on May 19, 2010, 04:15:45 pm
Post by: Ghost Of Highbury on May 19, 2010, 04:22:07 pm
hey jus a doubt .. isnt Watt already Joule/second ??
yess..it is, the ms says W, so i rote 18.75W
Post by: Ghost Of Highbury on May 19, 2010, 04:23:40 pm
from where do we get p = v^2/r
p = i^2*r
p = v*i
v = ir
p = i^2r..
Post by: WARRIOR on May 19, 2010, 04:26:57 pm
p = i^2*r
p = v*i
v = ir
p = i^2r..
I said P = V^2 / R... NOT
P = I^2 X R
Post by: Ghost Of Highbury on May 19, 2010, 04:29:44 pm
I said P = V^2 / R... NOT
P = I^2 X R
my bad, maybe that wasnt for me..
Post by: Ghost Of Highbury on May 19, 2010, 04:33:43 pm
I said P = V^2 / R... NOT
P = I^2 X R
p = v*i
v = ir
i = v/r
p = v*(v/r)
p = v^2/r
Post by: WARRIOR on May 19, 2010, 05:08:56 pm
Post by: Ghost Of Highbury on May 19, 2010, 05:13:26 pm
its simple formula mixed here and there..
u cud use all the formulas in other ones to get new ones..
Post by: WARRIOR on May 19, 2010, 05:16:00 pm
huh?yea i understand
its simple formula mixed here and there..
u cud use all the formulas in other ones to get new ones..
anwyya thanks :)
Post by: Ghost Of Highbury on May 19, 2010, 05:16:54 pm
Post by: WARRIOR on May 19, 2010, 05:48:25 pm
6 (b) (2)
15000?
Post by: J.Darren on May 19, 2010, 05:55:42 pm
http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Jun/0625_s09_qp_3.pdfThe area has no impact on the pressure when in a liquid, the pressure would be the same as 6 b i, 30,000 Pa.
6 (b) (2)
15000?
Post by: WARRIOR on May 19, 2010, 06:05:11 pm
The area has no impact on the pressure when in a liquid, the pressure would be the same as 6 b i, 30,000 Pa.o o new fact :o
thanks!
Post by: Ghost Of Highbury on May 19, 2010, 06:06:43 pm
The area has no impact on the pressure when in a liquid, the pressure would be the same as 6 b i, 30,000 Pa.
yes, the pressure exerted by a liquid = h*density*g
g = gravitational force..
h = height..
density = of the liquid..
not on the area..
Post by: Snake on May 20, 2010, 06:57:23 am
Post by: Snake on May 20, 2010, 08:21:19 am
Post by: The Golden Girl =D on May 20, 2010, 08:25:41 am
Guys can you please give me notes on the last section of Physics syllabus (Radiation). Much appreciated peeps :)
i guess u can find it here :
http://www.astarmathsandphysics.com/igcse_physics_notes_menu.html
Post by: Vin on May 20, 2010, 08:26:14 am
check here if u want notes
http://freeexampapers.com/Dndex.php?d=SUdDU0UvUGh5c2ljcy9DSUUvUmVzb3VyY2Vz
Post by: Vin on May 20, 2010, 08:30:10 am
Also guys small doubt here. P1 2009 oct/nov Q31. I dont understand why it is C.
dude its D .. variant 1 .. thermistor .. as temperature increases resistance decreases so reading in ammeter increases
variant 2 .. C because 5A is the only one which 6A .. to protect the wire carrying a current of 6A a smaller value of fuse should be used .. its not 3A because the fuse would "beak" and the appliance ca no longer be used
..
hello u there ??
Post by: Snake on May 20, 2010, 08:48:27 am
Post by: Vin on May 20, 2010, 08:50:21 am
yea .. 6A .. otherwise the wire might melt of high temperature
Post by: Snake on May 20, 2010, 08:51:38 am
i guess u can find it here :
http://www.astarmathsandphysics.com/igcse_physics_notes_menu.html
Used this one, but I'm wondering if there is another site or something, thxk.
Post by: The Golden Girl =D on May 20, 2010, 08:54:28 am
Used this one, but I'm wondering if there is another site or something, thxk.
maybe VIN or A@di have , ask them ;)
Post by: Vin on May 20, 2010, 10:33:21 am
http://freeexampapers.com/Dndex.php?d=SUdDU0UvUGh5c2ljcy9DSUUvUmVzb3VyY2VzLzQgUmFkaW9hY3Rpdml0eQ==
http://www.freeexampapers.us/IGCSE/Physics/CIE/Resources/Radioactivity%202009%20pp1-22.pdf
check for some more .. here
http://freeexampapers.com/Dndex.php?d=SUdDU0UvUGh5c2ljcy9DSUUvUmVzb3VyY2Vz
Post by: J.Darren on May 20, 2010, 01:08:37 pm
Yea I was talking about variant 2, thanks for explaining. so it had to be less then 6, because 6v is the most the wire can carry?A. 1 A - Would not serve the purpose as the appliance normally uses a current of 3 A, the fuse would be useless if it melts before the appliance can be switched on normally.
B. 3 A - Again there is no point at introducing a fuse if the appliance normally uses a current of 3 A, the fuse would be useless if it melts before the appliance can be switched on normally.
C. 5 A - When operating at normal, the current would rise to 4 A at maximum, we don't want a fuse with terminating current at 4 A or below. The cable to the appliance is designed for currents up to 6 A, hence 6 A is teh maximum that it can carries, nor do we want that.
D. 13 A - The cable to the appliance is designed for currents up to 6 A. A current that is larger than 6 A would damage the cable, we want a fuse that would automatically melts before the cable is in peril of damaging.
Post by: 2010 on May 20, 2010, 01:10:58 pm
Even though i've studied this chapter from 3 different books, i'm not able to solve most past paper question related to the topic....
Post by: WARRIOR on May 20, 2010, 01:24:17 pm
Can someone please tell me what i am supposed to know in RADIOACTIVITY..?
Even though i've studied this chapter from 3 different books, i'm not able to solve most past paper question related to the topic....
what questions ? ill explain them to you if i can
Post by: Fastal on May 20, 2010, 01:36:47 pm
P=hdg only applicable to liquids
cuz i used that formula for air pressure in a past paper
Post by: 2010 on May 20, 2010, 01:38:43 pm
what questions ? ill explain them to you if i canActually my teacher told me that we should try solving papersds from 1995 onwards because they are repeating questions from old papers..
There's no specific question....i'm just not able to solve any question related to radioactivity (from scattering to isotopes to hteir absorbing properties) :(
Post by: WARRIOR on May 20, 2010, 01:48:35 pm
Actually my teacher told me that we should try solving papersds from 1995 onwards because they are repeating questions from old papers..ATOMIC PHYSICS.
There's no specific question....i'm just not able to solve any question related to radioactivity (from scattering to isotopes to hteir absorbing properties) :(
You should know verythign is made of extreemtly small atoms and at the centre there is a nucleas Which contain nucleons ( protons + neutrons ) .Around the nuclease there are electrons but we totally ignore that they exist in physics ( atomic anway )
You should know the charge and atomic mass unit
charge masss
Electrons -1 1/1840 ..which is basically zero and you can say that in exmas
protons + 1 1
nuetron - 0 1
We have elements and we have proton numbers ( DOWN ) 6 and mass number (UP) 14
Proton number tells you the amount of protons adn electron 14
Mass number ttells what is in the nucleus ( protons + neutrons ). So for exacmple , If element is C
6
the proton number down ( 6 ) which means also has 6 protons and eleectron . The mass number up, tellls us proton + nucleans and we know proton therefore neutron = 14-6=8
ISOTOPS
ATOMS OF SAME ELEMENT WITH DIFFEENT NUCLEON NUMBER BUT SAME PROTON NUMBER
127 131
EX IODINE IODINE
53 53
IM COMPLETEING ..HOLD ON
Post by: WARRIOR on May 20, 2010, 01:56:20 pm
THE GOLD EXPERIMENT ( ALPHA PARTICLES ARE + )
ALPHA PARTICLES WRER FIRE THROUGH VERY THIN GOLD FOIL AND A DETECTOR WAS MOVED AROUND THE FOIL TO CHECK THE MOVEMENTS ( I.E DEFLECTION - TWISTS - ETC)
http://www.iop.org/activity/education/Teaching_Resources/Teaching%20Advanced%20Physics/Atomic%20and%20Nuclei/Images%20500/img_mid_5329.gif
this is whats happening ^ ..you see the yellow point in the middle of of the clouds,, see how small the nucleus is compared to it?
ANYWAY YOU HAVE TO EXPLAIN WHAT IS GOING ON !
THE ALPHA PARTICLES GOING STRAIGHT WIHTOUT DEFLECTION TELLS THAT THE ATOM IS NEARLY ALL EMPTY!! SPACE APART FROM THE NUCLEUS! AND SO..
THE ALPHA PATICLES THAT WERE DEFLECTED BY SMALL ANGLES SHOW US THAT THE NUCLEAS WHICH REPELLED ALPHA PARTICLS WHICH PASSED VERY VERY VERY VERY VERY CLOSE TO IT GOT REPELLED ..TELLS US THAT NUCLEUS IS POSOTIVE. AND SO
THE ALPHA PARTICLES (ABOUT 1 IN 8000 ) WERE SURPRISINGLY BOUNCED BACK !!!!!!!!!!!!!!!!> THIS TELLS US THAT THE ALPHA PATICLES COLLIDED WITH THE TINY WEENY TINY WEENY POSITIVE NUCLEASE , SO IT TELLS US THAT IT HAS A LAAAAARGE MASSSSSSSSSSSSSSSSSS altho it is very very very teeeny weeny space between the atom but it has a high masss
Post by: WARRIOR on May 20, 2010, 02:10:47 pm
UNSTABLLE NUCLEASE BREAKS UP AND RELEASES ENRGY IN FORM OF RADIOACTIVITY
WE ARE ALL EXPOSED TO BACKGROUND RADIOACTIVITY by radioactive materials in rocks , the air etc but this is very small so it doesnt affect us and does not produce any noticeable affects on our health!
BACKGROUND RADTIATION IS = 20 COUNT PER MINUTE but sicne radioacttivity is A RANDOM process it varies slightily
now we have 3 types of radiation
ALPHA PARTICLES
an alpha particle is made up of 2 protons and 2 neutrons .
It has posotive charrge (2 + ) .
Can be stopped by few mm paper or a few cm of air thats why you can avoid alpha radiation by stayin 6cm away from it !
Mass 4 units ( VERY HEAVY thats why its hard to deflect towards the negative plates )
Speed : slooooooooow caz its heavvvyyyyyyy 10% SPEED OF LIGHT
Ability to ionise : STRONG !! +4 ..OMG!!! :o :o :o
DEFELCTION BY ELECTRIC FIELD : DEFLECT A LITTLE TOWARDS THE NEGATIVE PLATES
DEFLECTIIN BY MAGNETIC FIELD : DEFLECT SAME DIRECTION OF WIRE ( LEFT HAND FLEM.) BUT DIFFRENT DIRECTION OF BETA
DETECTORs : PHOTOHRAPHIC FILM. CLOUD CHAMBER . THINE WINDOW G-M TUBE . SPARK COUNTER
BETA PARTICLE
Define : Fast moving electron ( light ) emitte from the nuclease when a neturon splits up into a proton and an elctron !.
It has -ve charve ( -1)
Can be stopped by a few mm of Aluminium
MASS 1/1840 = 0
SPEED : 50% SPEED OF LIGHT FAST OMG OMG
Abiltiy to ionise : Weak -1 nooblet
Deflection by electric field : tWARD +VE PLATE
deflection by mag """"""""" : OPPOSITE DIRECTION OF WIRE
DETECTORS : PHOTGRPAHIC GILM. CLOUD CHAMBER . G-M TUBE
GAMMA RAYS
IS A WAVE WIHT VERY VERY SHORT WAVELENGTH ( SHRTEST ) .I
LOOOOOOOOOL NO CHRGE AHAHHAHAHAH
MASS : ZEROOOOOOOO NOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOBY
SPEED : SPEED OF LIGHT :o :o :o :o :o :o :o WOOOOAAAH!
REMEMBER : REDUCED BUT NOT STOPPED BY LEAD!!!!!!!!!!!
Abillity to ionis : pffffffffttttt very weak as no charge..almost neglectable !
DEFLECTION BY ELEC : NO
DEFLECT BY MAGE : NO
DETECECTORS : PHOT FILM . CLOUD CHAMBER . G-M TUBE
Post by: J.Darren on May 20, 2010, 02:16:24 pm
EVIDENCE FOR THE NUCLEAR MODELSay for instance when a beam of alpha particle is released at the gold nucleus, it gets diverged into three paths : one that shoots directly at the gold nucleus, one that goes past the gold nucleus, one that travels away from the gold nucleus.
THE GOLD EXPERIMENT ( ALPHA PARTICLES ARE + )
ALPHA PARTICLES WRER FIRE THROUGH VERY THIN GOLD FOIL AND A DETECTOR WAS MOVED AROUND THE FOIL TO CHECK THE MOVEMENTS ( I.E DEFLECTION - TWISTS - ETC)
http://www.iop.org/activity/education/Teaching_Resources/Teaching%20Advanced%20Physics/Atomic%20and%20Nuclei/Images%20500/img_mid_5329.gif
this is whats happening ^ ..you see the yellow point in the middle of of the clouds,, see how small the nucleus is compared to it?
ANYWAY YOU HAVE TO EXPLAIN WHAT IS GOING ON !
THE ALPHA PARTICLES GOING STRAIGHT WIHTOUT DEFLECTION TELLS THAT THE ATOM IS NEARLY ALL EMPTY!! SPACE APART FROM THE NUCLEUS! AND SO..
THE ALPHA PATICLES THAT WERE DEFLECTED BY SMALL ANGLES SHOW US THAT THE NUCLEAS WHICH REPELLED ALPHA PARTICLS WHICH PASSED VERY VERY VERY VERY VERY CLOSE TO IT GOT REPELLED ..TELLS US THAT NUCLEUS IS POSOTIVE. AND SO
THE ALPHA PARTICLES (ABOUT 1 IN 8000 ) WERE SURPRISINGLY BOUNCED BACK !!!!!!!!!!!!!!!!> THIS TELLS US THAT THE ALPHA PATICLES COLLIDED WITH THE TINY WEENY TINY WEENY POSITIVE NUCLEASE , SO IT TELLS US THAT IT HAS A LAAAAARGE MASSSSSSSSSSSSSSSSSS altho it is very very very teeeny weeny space between the atom but it has a high masss
Also if it is a beam of alpha particle, you may as well treat it as a current and use Fleming's Left-hand rule in calculating whether it is traveling away or into the paper as alpha particle is positively charged. In the case for beta particle, reverse the direction of the current.
Post by: J.Darren on May 20, 2010, 02:24:41 pm
RADIOACTIVITY ( UNSTABLE ELEMENTS )Those radiation is called radioactive decay. We have alpha particle decay where 2 protons and 2 neutrons (Helium) is gone from a Radium-226 nucleus, the proton number got reduced to 86, a Radon nucleus is formed. In a beta decay a neutron in Iodine-131 gets converted to a proton, forming Xenon-131 (same mass number, but an increase in the proton number), an electron and anantineutrino is released. There is another type of beta-decay where a proton gets converted into a neutron, an electron and neutrino is released.
UNSTABLLE NUCLEASE BREAKS UP AND RELEASES ENRGY IN FORM OF RADIOACTIVITY
WE ARE ALL EXPOSED TO BACKGROUND RADIOACTIVITY by radioactive materials in rocks , the air etc but this is very small so it doesnt affect us and does not produce any noticeable affects on our health!
BACKGROUND RADTIATION IS = 20 COUNT PER MINUTE but sicne radioacttivity is A RANDOM process it varies slightily
now we have 3 types of radiation
ALPHA PARTICLES
an alpha particle is made up of 2 protons and 2 neutrons .
It has posotive charrge (2 + ) .
Can be stopped by few mm paper or a few cm of air thats why you can avoid alpha radiation by stayin 6cm away from it !
Mass 4 units ( VERY HEAVY thats why its hard to deflect towards the negative plates )
Speed : slooooooooow caz its heavvvyyyyyyy 10% SPEED OF LIGHT
Ability to ionise : STRONG !! +4 ..OMG!!! :o :o :o
DEFELCTION BY ELECTRIC FIELD : DEFLECT A LITTLE TOWARDS THE NEGATIVE PLATES
DEFLECTIIN BY MAGNETIC FIELD : DEFLECT SAME DIRECTION OF WIRE ( LEFT HAND FLEM.) BUT DIFFRENT DIRECTION OF BETA
DETECTORs : PHOTOHRAPHIC FILM. CLOUD CHAMBER . THINE WINDOW G-M TUBE . SPARK COUNTER
BETA PARTICLE
Define : Fast moving electron ( light ) emitte from the nuclease when a neturon splits up into a proton and an elctron !.
It has -ve charve ( -1)
Can be stopped by a few mm of Aluminium
MASS 1/1840 = 0
SPEED : 50% SPEED OF LIGHT FAST OMG OMG
Abiltiy to ionise : Weak -1 nooblet
Deflection by electric field : tWARD +VE PLATE
deflection by mag """"""""" : OPPOSITE DIRECTION OF WIRE
DETECTORS : PHOTGRPAHIC GILM. CLOUD CHAMBER . G-M TUBE
GAMMA RAYS
IS A WAVE WIHT VERY VERY SHORT WAVELENGTH ( SHRTEST ) .I
LOOOOOOOOOL NO CHRGE AHAHHAHAHAH
MASS : ZEROOOOOOOO NOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOBY
SPEED : SPEED OF LIGHT :o :o :o :o :o :o :o WOOOOAAAH!
REMEMBER : REDUCED BUT NOT STOPPED BY LEAD!!!!!!!!!!!
Abillity to ionis : pffffffffttttt very weak as no charge..almost neglectable !
DEFLECTION BY ELEC : NO
DEFLECT BY MAGE : NO
DETECECTORS : PHOT FILM . CLOUD CHAMBER . G-M TUBE
Half-life is the time it takes for a radioactive isotope to halve its size in a decay.
Alpha particle and beta particle would ionise Argon gas inside a Geiger-Muller tube, this is due to their respective positive / negative charge.
By the way in an experiment that requires to measure the number of alpha / beta particles emitted, be sure to subtract the background reading.
Post by: WARRIOR on May 20, 2010, 02:28:19 pm
Post by: WARRIOR on May 20, 2010, 02:43:04 pm
AN ION IS AN ATOM WHICH GAINED OR LOST ELECTRONS
RADIATION CAN IONISE AIR BY KNOCKIN ELECTRONS FROM ATOM
FROM ABOVE WE KNO THE BEST ALPHA THEN BETA THEN GAMMA
SPARK COUNTER
http://www.promma.ac.th/chemistry/element_property/images/spark.gif
RADIUM IOONISES AIR . POSOTIVE IONS MOVE TO CATHODE AND NEGATIVE MOVE TO ANODE. ALPHA PARTICLES CAN BE DETECED USING SPARK COUNTER SINCE ALPHA PARTICELS ARE EXCELLENT AT IONISING
G-M TUBE
http://williamson-labs.com/images/gmtube-273.gif
A tube that contains a high voltage inside a metal case that is earthed
WHY HIGH VOLTAGE ? TO ATTRACT THE CHARGED FROM TO ANODE ADN CATHODE
remember the g-m tube can detect radiations but CANNOT differentiate between the three types.
When radiation enters the tube it ionise the gas inside the tube adn there is flow of charge w hich prouduces a spark from the wire to the case. Th e posotive ions move to the cathode adn the negative electrons move to anode.
An ampliver connected to the tube clicks every time there is a spark
HOW TO DIFFERNTANE??
WELL YOU HAVE TO GET THE RADIOACTIVE SOURCE and put PAPER , ALUMINIUM AND LEAD BETWEEN the source adn the DETECTOR! (remember some can pass and some cant!)
remember always take BACKGROUND RADIATION FIRST! lets say its 20 !!
so example COUNTS PER MIN ABSORBER USED
4000 NON
2700 THIN PAPER
20 aluminium
this means some counnts are stopped ! that means this source produced ALPHA PARTICELS SINCE ITS STOPPED BY PAPER !
but wait !!!!!!!! counts did go to 20 ..that means there is also soem other radioacttive stuff.. NOW WE ADD ALUMINIUM and counts dropped to 20 that means there are beta particels!!!!!!!! but count dropped to 20 and so there are no otehr radioactive like gamma..but if there was gamma then there would still be counts!
CLOUD CHAMBER
IM NOT SURE IF ITS ON SYLLABUS SO I WONT EXPLAIN UNTIL SOME1 TELLS ME ITS ON :p
Thin window is necssary so that ALPHA PARICLES CAN ENTER G-M TUBE ( REMMBER ITS STOPPED BY PAPER !)
Post by: WARRIOR on May 20, 2010, 02:56:39 pm
KEEP ALL RADIOACTIVE IN LEAD CONTAINORS . ( LEAD STOPS ALPHA BETA AND REDUCES GAMMA)
KEEP AS FAR AWAY FROM SOURCE AND USE TONGS TO HANDLE
KEEP EXPOSURE TIME AS SHORT AS POSSIBLE
BURY WASTES DEEP IN GROUND
RADIACTIVTY BADGE
-------------------------------
RADIOACTIVE DECAY
NUCLEI OF ATOMS OF A RADIOACTIVE SUBST ARE UNSTABLE AND SOONER OR LATER THEY WIL BREAK UP OR DECAY FORMIN A MORE STABLE ONE . THIS MEANS A NEW ELEMEMTN IS FORMED . NO ONE KNOWS WHEN A NUCLEAUS WIL BREAK UP , IT IS ENTIRELY RANDOM PROCESS
ALPHA DECAY
WHN A SUBTANCE EMITES ALPHA PARTICLES IT LOSES TWO PRTOTNS AND 2 NEUTRONS FROM ITS NUCLEUS
THE NUCLEON NUMBER IS REDUCED BY 4 AND PROTON NUMBER REDDUCED BY 2
EQUATION
A A-4 + 4
X ----> Y a
Z Z-2 2
BETA DECAY
RELEASE WHN A NETURON SPLITS UP INTO A PROTON AND AN ELECTRON
EQUATION
A A 0
X ---> Y + e
Z Z+ 1 -1
Gamma decay
No affect on nucleas of an atom as it has no mass or charge !
Post by: WARRIOR on May 20, 2010, 03:09:38 pm
TIME TKEN FOR THE ACTIVITY OF THE SOURCE TO HALVE
THE HALF LIFE IS TH ETIME TAKE FOR THE SOURCE TO LASE HALF ITS RADIOACTIVE ATOMS
DECAY IS RANDOM
Some isotopes have a short half -life and they decay very quick while others have a vey long adn take a long time. Value of half life is not affected by temp , presure etc.
EXAMPLE :
IODIE 131 HAS A HALF LIFE OF 8 DAYS WHEN IT DECAYS IT TURNS TO XENON 131
IF WE START OFF WITH 80MILLION IODINE 131 , EIGHT DAYS LATER THERE WILL BE 40 MILLION IDIOEN 131. THE NUMBER OF XENON-131 NUCLEI ARE INCREASE FROM ZERO TO 40 MILLION
Another 8 days ...HALF OF 40 IS ..HMMM .. 20 !..SO 20MILLION IDONE 131 AND XENEON WILL BE 60 M ...GET THE POINT??
DECAY CURVE
TOO HARD TO EXPLAIN SO YOU SHOULD VIISIT THIS SITE
http://www.astarmathsandphysics.com/igcse_physics_notes/igcse_physics_notes_radioactivity_and_half_life.html
Post by: WARRIOR on May 20, 2010, 03:18:32 pm
TO DETECT CRACKS IN UNDERGROUND PIPES. THE RADIOACTIVE GAS LEAKS OUT THRO THE CRACK AND CAN BE DETECED THE A G-M COUNTER
TYPE OF SOURCE : BETA EMITTER CAZ IT CAN PENTERATE SOIL AND PIPES . ALSO USE 1 WITH SHORT HALF LIFE SO ITS RAADIOACTIVITY DOESNT CONITUE FOR LONG TIME SO IT DOESN POISON PEOPLE
why not gamma why not alpha ? ask yourself?
---------------------------
IN PAPER FACTORIES WHERE THICKNESS OF PAPER IS MEASURES BY SHOWING HOW MUCH RADIATION PASSES THRO THE PAPER. IF TOO MUCH RAD. PASSES TRHO , THEN PAPER IS TOO THIN
TYEP OF SOUURC : BETA CAZ CAN EASILY PASS TRHO PAPER AND COUNTS CAN BE DECREASSED BY THICK PAPER WITH LONG HALF LIFE SO THAT ITS ACTIVITY IS CONSTANT .DUUH U DONT WANT IT TO FINISH DO YA? DOO YAAA ?????
why not gamma why not alpha ? ask yourself?
---------------------------------
EQUIPMENT IS HOSPITALS ARE STERILISED USING RADIATION
TYPE OF SORUCE GAMMA EMITTER WITH RASONABLY SHORT HALF LIFE S
GAMMA KILLS BACTERIA :@ :@
----------------------------------------
CHEEEEEEEEERS ATOMIC PHYS IS DONE
Post by: Helium on May 20, 2010, 04:23:51 pm
Its in phys syllabus i know whats hooke law but the i use says nothing about that expression. :-\
Post by: WARRIOR on May 20, 2010, 04:27:37 pm
It says that force is proportiional to extension
F IS FORCE
K IS SPRING CONSTANT X IS EXTENSION
The constant is defined as how much force is need to stretch the spring by 1m adn the unit is N/m or N/mm or N/cm
K = F/x
a spring with a large spring constant is hard to stretch ( needs alot of force ) while one with small spring constant need less
Post by: 2010 on May 20, 2010, 04:41:22 pm
That really helped!:D
Post by: Vin on May 20, 2010, 05:03:55 pm
2010 luv ur signature !! XD
Post by: Fastal on May 20, 2010, 05:30:18 pm
guys isanyone?
P=hdg only applicable to liquids
cuz i used that formula for air pressure in a past paper
Post by: Vin on May 20, 2010, 05:31:51 pm
anyone?
which paper ?? depends on the context ..
Post by: Helium on May 20, 2010, 05:45:01 pm
this is about springs
It says that force is proportiional to extension
F IS FORCE
K IS SPRING CONSTANT X IS EXTENSION
The constant is defined as how much force is need to stretch the spring by 1m adn the unit is N/m or N/mm or N/cm
K = F/x
a spring with a large spring constant is hard to stretch ( needs alot of force ) while one with small spring constant need less
Thanks that was a very good explanation ;D
Post by: guMnam on May 21, 2010, 07:32:27 am
Post by: WARRIOR on May 21, 2010, 07:37:36 am
@ kimo jesus......are u a teacher or wat..:P nice stuff gud work:Dlol no :P im doing the ig with you guys :p
just a good skool i guess and some stuff i plainly taken off the book ::)
Post by: WARRIOR on May 21, 2010, 07:58:44 am
October november 2004
Describe the action of a tranistor?
can you say When voltage accross the base and emitter iis large enough the transistor switches on and aloows a large current to pass
mark scheme asnwers : http://www.freeexampapers.us/IGCSE/Physics/CIE/2004%20Nov/0625_w04_ms_3.pdf ( question 10 2)
i dont understand any ^
Post by: Vin on May 21, 2010, 08:18:02 am
10 a) a transistor can be used as a switch
b) the base current of the transistor can be varied, works only when Voltage in base is greater than 0.6 V , small change in base current can produce a large change in collector or emitter current
Post by: WARRIOR on May 21, 2010, 08:47:08 am
10 a) a transistor can be used as a switch
b) the base current of the transistor can be varied, works only when Voltage in base is greater than 0.6 V , small change in base current can produce a large change in collector or emitter current
ok but what do u mean by
Post by: Vin on May 21, 2010, 09:01:27 am
there are two current paths through a transistor .. base emitter and collector emitter which is via base ..A voltage or current applied to the terminals changes the current flowing through another pair of terminals.Because the output power can be much more than the controlling input power, the transistor provides amplification of a signal.
The essential usefulness of a transistor comes from its ability to use a small signal applied between one pair of its terminals to control a much larger signal at another pair of terminals. This property is called gain. A transistor can control its output in proportion to the input signal, that is, can act as an amplifier.
Post by: WARRIOR on May 21, 2010, 09:08:51 am
there are two current paths through a transistor .. base emitter and collector emitter which is via base ..A voltage or current applied to the terminals changes the current flowing through another pair of terminals.Because the output power can be much more than the controlling input power, the transistor provides amplification of a signal.i see thanks !
The essential usefulness of a transistor comes from its ability to use a small signal applied between one pair of its terminals to control a much larger signal at another pair of terminals. This property is called gain. A transistor can control its output in proportion to the input signal, that is, can act as an amplifier.
Post by: Vin on May 21, 2010, 09:18:58 am
just a property .. u jus hav to know them .. nothing to understand i suppose ..
Post by: Ghost Of Highbury on May 21, 2010, 09:22:02 am
u have to understand them..very important..
check june 07 Q10 b)...abt transistors..
a guy called "cooldude" had answered it beautifully ...if u want i can get that explanation for u..
Post by: Vin on May 21, 2010, 09:34:48 am
yea please .. our teacher never taught us properly .. :\
thanks .. :)
Post by: Ghost Of Highbury on May 21, 2010, 09:54:56 am
see if we want to change the temperature at which the lamp switches on, we have to change the value of resistance R1. if we increase the value of the resistance then more voltage will flow through the transistor and if we decrease the voltage then less voltage will flow through the transistor. therefore if we assume that the amount of heat falling on the thermistor is constant then when we increase or decrease the value of R1 so will the value of the voltage passing through the tranistor will change. so if we want to make the lamp switch on at a different temperature we change the value of R1 because if the heat is falling on the thermistor and thus its resistance decreasing then if the base voltage is enough to switch on the transistor it will light however decreasing the value of the resistor R1 will cause the voltage flowing through the transistor to be too less to switch it on (this is if we want to make the temperature at which the lamp lights more; just explain the opposite thing if u want the temperature at which the transistor lights lower than it is and also u dnt need to expalin all this, ive done this to help u understand it and if u want a shortened version ill be happy to help). therefore in short the temperature at which the lamp lights can be changed by changing the value of R1. (the lamp lights when the base voltage becomes enough for the lamp to switch on)
Post by: WARRIOR on May 21, 2010, 10:11:25 am
ans10b)
see if we want to change the temperature at which the lamp switches on, we have to change the value of resistance R1. if we increase the value of the resistance then more voltage will flow through the transistor and if we decrease the voltage then less voltage will flow through the transistor. therefore if we assume that the amount of heat falling on the thermistor is constant then when we increase or decrease the value of R1 so will the value of the voltage passing through the tranistor will change. so if we want to make the lamp switch on at a different temperature we change the value of R1 because if the heat is falling on the thermistor and thus its resistance decreasing then if the base voltage is enough to switch on the transistor it will light however decreasing the value of the resistor R1 will cause the voltage flowing through the transistor to be too less to switch it on (this is if we want to make the temperature at which the lamp lights more; just explain the opposite thing if u want the temperature at which the transistor lights lower than it is and also u dnt need to expalin all this, ive done this to help u understand it and if u want a shortened version ill be happy to help). therefore in short the temperature at which the lamp lights can be changed by changing the value of R1. (the lamp lights when the base voltage becomes enough for the lamp to switch on)
hmm llook how i thought of it and tell me if its right or wrong
When Temp is high n the thermistor its resistance decreases... therefore the resistance accruse teh base and emittor is high enough to switch on the transistor and therfore lamp is on
If thermitor has low voltage thn the normal resisor has high voltage.( lets say total voltage is 10 ) so if u increase the resistance of the varable resistor from x to x ..it will get more voltage..and so there will be less voltage for the thermistor ..and so heat wil have to decrease it by less amount ! to get to a low resistance where low voltage
makes sence? nope.
Post by: WARRIOR on May 21, 2010, 10:13:39 am
why does the value of R1 affect the voltage of the transistor..? why not the theristor ?
crap im confused :(
Post by: Ghost Of Highbury on May 21, 2010, 10:42:48 am
wait a minute
why does the value of R1 affect the voltage of the transistor..? why not the theristor ?
crap im confused :(
If we want the lamp to switch on at a different temperature, say higher temperature.
The normal heat on the transistor reduces the resistance of the thermistor, thus more voltage flows through the transistor and switches on the lamp.
HOWEVER, we dont want the lamp to switch on because of normal heat, wen need higher temp. to switch it on, what to do we do??
for this, we need to decrease the resistance of R1, which allows more voltage to flow through R1, thus reducing the voltage flowing through the transistor. For more voltage to flow through the transistor again, a higher temperature (more heat ) will be required which will reduce the resistance of the thermistor further, and thus the lamp will switch on again.
Post by: WARRIOR on May 21, 2010, 10:55:46 am
If we want the lamp to switch on at a different temperature, say higher temperature.i got i got it now
The normal heat on the transistor reduces the resistance of the thermistor, thus more voltage flows through the transistor and switches on the lamp.
HOWEVER, we dont want the lamp to switch on because of normal heat, wen need higher temp. to switch it on, what to do we do??
for this, we need to decrease the resistance of R1, which allows more voltage to flow through R1, thus reducing the voltage flowing through the transistor. For more voltage to flow through the transistor again, a higher temperature (more heat ) will be required which will reduce the resistance of the thermistor further, and thus the lamp will switch on again.
but if teh resistance of R1 i low doesnt it mean less voltage goes to it?
Post by: Ghost Of Highbury on May 21, 2010, 11:00:58 am
i got i got it now
but if teh resistance of R1 i low doesnt it mean less voltage goes to it?
Decreasing the resistance will allow more current to pass through it thus decreasing the voltage at the thermistor.
Post by: guMnam on May 21, 2010, 11:42:40 am
Post by: astarmathsandphysics on May 21, 2010, 11:55:58 am
eg 12V with an output resistance of 4ohm and circuit resistance of 2 ohm
output voltage=4/(4+2)*12=8V
Post by: WARRIOR on May 21, 2010, 12:02:58 pm
potential divider divides voltage in ratio of resistances.does it matter where the lamp is?
eg 12V with an output resistance of 4ohm and circuit resistance of 2 ohm
output voltage=4/(4+2)*12=8V
to the right of the thermistor or to the right of the normal resistor?
Post by: guMnam on May 21, 2010, 12:08:50 pm
potential divider divides voltage in ratio of resistances.sry i didnt get it...can u elaborate
eg 12V with an output resistance of 4ohm and circuit resistance of 2 ohm
output voltage=4/(4+2)*12=8V
Post by: ambitious94 on May 21, 2010, 12:24:00 pm
I'm new to the forum, and found this thread rlly helpful. Man, some of u r rlly smart :) and very helpful too!
I have a couple of questions that i found trouble with while solving in the past papers. All these questions are mainly from Nov 07 (Ppr 3)
1) How do u draw a diagram to represent a sound wave or a longitudinal wave? I usually draw vertical lines with spacings for compressions and rarefactions, is that correct? How would you mark the wavelength on it?
2) Secondly, in electromagnetic induction, wat is more appropriate to say: am e.m.f is induced, or a current, or a voltage? :S
3) How many cms of Al sheets would be required to completely block B-particles from a source?
4) In Nov 07, can anyone please explain how to draw the logic gates, and why!! I thought abt making it a NAND gate, but it was wrong. What's your theory abt this?
Thanks in advance :)
Post by: guMnam on May 21, 2010, 01:17:45 pm
Hi,actually u can use both emf and voltage but voltage is beter
I'm new to the forum, and found this thread rlly helpful. Man, some of u r rlly smart :) and very helpful too!
I have a couple of questions that i found trouble with while solving in the past papers. All these questions are mainly from Nov 07 (Ppr 3)
1) How do u draw a diagram to represent a sound wave or a longitudinal wave? I usually draw vertical lines with spacings for compressions and rarefactions, is that correct? How would you mark the wavelength on it?
2) Secondly, in electromagnetic induction, wat is more appropriate to say: am e.m.f is induced, or a current, or a voltage? :S
3) How many cms of Al sheets would be required to completely block B-particles from a source?
4) In Nov 07, can anyone please explain how to draw the logic gates, and why!! I thought abt making it a NAND gate, but it was wrong. What's your theory abt this?
Thanks in advance :)
Post by: Ghost Of Highbury on May 21, 2010, 01:26:12 pm
Hi,
I'm new to the forum, and found this thread rlly helpful. Man, some of u r rlly smart :) and very helpful too!
I have a couple of questions that i found trouble with while solving in the past papers. All these questions are mainly from Nov 07 (Ppr 3)
1) How do u draw a diagram to represent a sound wave or a longitudinal wave? I usually draw vertical lines with spacings for compressions and rarefactions, is that correct? How would you mark the wavelength on it?
2) Secondly, in electromagnetic induction, wat is more appropriate to say: am e.m.f is induced, or a current, or a voltage? :S
3) How many cms of Al sheets would be required to completely block B-particles from a source?
4) In Nov 07, can anyone please explain how to draw the logic gates, and why!! I thought abt making it a NAND gate, but it was wrong. What's your theory abt this?
Thanks in advance :)
http://www.antonine-education.co.uk/Physics%20A%20level/Unit_2/Waves/Progressive_Waves/wav_9.gif
Post by: WARRIOR on May 21, 2010, 01:48:13 pm
If we want the lamp to switch on at a different temperature, say higher temperature.oki doki thanks man ! i understood it ..my concept was wrogn but i used to goet right asnwers for some reason .. now that i understand it <3 cheers + rep !
The normal heat on the transistor reduces the resistance of the thermistor, thus more voltage flows through the transistor and switches on the lamp.
HOWEVER, we dont want the lamp to switch on because of normal heat, wen need higher temp. to switch it on, what to do we do??
for this, we need to decrease the resistance of R1, which allows more voltage to flow through R1, thus reducing the voltage flowing through the transistor. For more voltage to flow through the transistor again, a higher temperature (more heat ) will be required which will reduce the resistance of the thermistor further, and thus the lamp will switch on again.
Post by: ambitious94 on May 21, 2010, 02:53:39 pm
actually u can use both emf and voltage but voltage is beterthanks :)
Post by: guMnam on May 21, 2010, 03:01:53 pm
thanks :)anetyme mate:D
Post by: Ghost Of Highbury on May 21, 2010, 03:23:29 pm
oki doki thanks man ! i understood it ..my concept was wrogn but i used to goet right asnwers for some reason .. now that i understand it <3 cheers + rep !
It was written by cooldude, as i said. Part of the thanks goes to him. Glad the latter explanation helped too :P
Post by: ambitious94 on May 21, 2010, 03:59:03 pm
Both questions r from Nov 2008:
1) Q5(c) Using a 40W heater, 16.3g of ice is melted in 2 minutes. The heater is then switched off. In a further 2 minutes, 2.1g of ice is melted.
Calculate the value of specific latent heat of fusion of ice from these results.
2) Q6(b) What's the formula for the refractive index? sinr/sini or sini/sinr? Which is the incident and refracted ray? :S
Post by: holtadit on May 21, 2010, 04:12:41 pm
new doubts...;)
Both questions r from Nov 2008:
1) Q5(c) Using a 40W heater, 16.3g of ice is melted in 2 minutes. The heater is then switched off. In a further 2 minutes, 2.1g of ice is melted.
Calculate the value of specific latent heat of fusion of ice from these results.
2) Q6(b) What's the formula for the refractive index? sinr/sini or sini/sinr? Which is the incident and refracted ray? :S
COnfused with the same question.... Why do you do 16.3 - 2.1 ???
Post by: Vin on May 21, 2010, 04:21:03 pm
power is nothing but Joules per second
heat (Q) = 40 J/sec * 120 sec
Q = 4800 J
mass = 16.3-2.1 = 14.2
as the mass melted by the heater is only till 2.1g
4800 = 14.2 * L
L= 338 J/g
lemme check the other ques
ALWAYS formula for refractive index depends from which medium it passes
eg .
From denser to rarer (glass to air) = sin r /sin i
From rarer to denser (air to glass = sin i / sin r
here its(glass to air) = sin r /sin i
sin r/sin 30 = 1.49
sin r = sin (30) * 1.49
r = sin-1(0.745)
=48.2 o
Post by: Ghost Of Highbury on May 21, 2010, 04:21:30 pm
COnfused with the same question.... Why do you do 16.3 - 2.1 ???
"see the question in a different way/manner.... u see 16.3 is not lost by the heater only... they gave u a hint tht excess heat (not from the heater ) was also applied to the ice..
what u need to do, is to take out tht excess heat (by subtracting) and u get the actuall heat supplied by the heater (which is needed for the equation)"
Post by: J.Darren on May 21, 2010, 04:28:34 pm
new doubts...;)heat is gained from the surroundings in the experiment, by measuring for another two minutes, you can work out the effect of heat gained from the surroundings (ice that were melted due to those heat), subtract that from the total amount of ice melted will get you the full amount of ice melted due to the energy supplied by the heater.
Both questions r from Nov 2008:
1) Q5(c) Using a 40W heater, 16.3g of ice is melted in 2 minutes. The heater is then switched off. In a further 2 minutes, 2.1g of ice is melted.
Calculate the value of specific latent heat of fusion of ice from these results.
2) Q6(b) What's the formula for the refractive index? sinr/sini or sini/sinr? Which is the incident and refracted ray? :S
Specific latent heat of fusion = ML
40 x 120 = (16.3 - 2.1) L
L = 338 J / g
n = sin i / sin r (from rarer to denser medium. if it is from denser to rarer medium, such as glass to air, then take the reciprocal, sin r / sin i)
Post by: Ghost Of Highbury on May 21, 2010, 04:30:20 pm
heat is gained from the surroundings in the experiment, by measuring for another two minutes, you can work out the effect of heat gained from the surroundings (ice that were melted due to those heat), subtract that from the total amount of ice melted will get you the full amount of ice melted due to the energy supplied by the heater.
Specific latent heat of fusion = ML
40 x 120 = (16.3 - 2.1) L
L = 338 J / g
n = sin i / sin r (from rarer to denser medium. if it is from denser to rarer medium, such as glass to air, then take the reciprocal, sin r / sin i)
yes, thats correct.
another thing to remember , is that the refractive index cannot be less than 1...so if u get a value less than 1, reverse the formula..
Post by: key04 on May 21, 2010, 04:34:14 pm
how was the exams???
i hope it was good.........
does anyone know any good website 4 bio,chem n phy notes???
i do need it...........
plz tell me......
Thanks in advance
Post by: WARRIOR on May 21, 2010, 04:36:02 pm
yes, thats correct.it depends if ur calculatin the angle of refraction/incidenc in a less dense medium its less than one
another thing to remember , is that the refractive index cannot be less than 1...so if u get a value less than 1, reverse the formula..
"""""""""""""""""""""""""""""""""""""""""""""""""""in a more dece medium its more than one
but when its for exaplm : calculate the refrative index from speeds. SPEED OF LIGHT IN AIR/ SPEED OF LIGHHT IN MEDIUM its always above 1
Post by: WARRIOR on May 21, 2010, 04:44:12 pm
http://www.freeexampapers.us/IGCSE/Physics/CIE/2003%20Nov/0625_w03_qp_3.pdf
question 11 (a) part 2
With flemmings L.H.R ..the wire moves up.. so beta particles should move the opposite way shouldnt it?
Post by: J.Darren on May 21, 2010, 05:07:56 pm
hmm confusionIt goes into the page ... Take a look at the final question of June 06.
http://www.freeexampapers.us/IGCSE/Physics/CIE/2003%20Nov/0625_w03_qp_3.pdf
question 11 (a) part 2
With flemmings L.H.R ..the wire moves up.. so beta particles should move the opposite way shouldnt it?
Post by: WARRIOR on May 21, 2010, 05:21:11 pm
It goes into the page ... Take a look at the final question of June 06.look at mark scheme :O
it says moves at smooth curve 90* to the magnetic field out of the page!
http://www.freeexampapers.us/IGCSE/Physics/CIE/2003%20Nov/0625_w03_ms_1+2+3+5+6.pdf
13th page
Post by: J.Darren on May 21, 2010, 05:27:49 pm
look at mark scheme :Ohttp://www.freeexampapers.us/IGCSE/Physics/CIE/2006%20Jun/0625_s06_ms_3.pdf
it says moves at smooth curve 90* to the magnetic field out of the page!
http://www.freeexampapers.us/IGCSE/Physics/CIE/2003%20Nov/0625_w03_ms_1+2+3+5+6.pdf
13th page
Fourth page :O
Post by: WARRIOR on May 21, 2010, 05:31:16 pm
http://www.freeexampapers.us/IGCSE/Physics/CIE/2006%20Jun/0625_s06_ms_3.pdfTHAT MEANS THERE IS A MISTAKE RIGHT :o :o :o :o :o :o :o :o :o :o :o :o
Fourth page :O
not my mistke cool
Post by: J.Darren on May 21, 2010, 05:46:10 pm
THAT MEANS THERE IS A MISTAKE RIGHT :o :o :o :o :o :o :o :o :o :o :o :oI do apologise. Clearly I have misread the question (November 03), I thought they are referring to a beam of alpha particle instead of beta particle :(
not my mistke cool
Post by: Vin on May 21, 2010, 05:47:08 pm
THERE IS NO PROB WITH THE MS
http://www.furryelephant.com/player.php?subject=physics&jumpTo=re/9D2s5
Post by: Fastal on May 21, 2010, 05:49:51 pm
"see the question in a different way/manner.... u see 16.3 is not lost by the heater only... they gave u a hint tht excess heat (not from the heater ) was also applied to the ice..
what u need to do, is to take out tht excess heat (by subtracting) and u get the actuall heat supplied by the heater (which is needed for the equation)"
yeah but it says
"16.3g of ice was melted in 2 minutes USING THE HEATER."
and "FURTHER 2.1g was melted"
cie messed up
Post by: J.Darren on May 21, 2010, 05:50:25 pm
wat u guys talking about ??I misread the question, that's all.
THERE IS NO PROB WITH THE MS
http://www.furryelephant.com/player.php?subject=physics&jumpTo=re/9D2s5
Post by: J.Darren on May 21, 2010, 05:52:28 pm
yeah but it saysReply #875 :D
"16.3g of ice was melted in 2 minutes USING THE HEATER."
and "FURTHER 2.1g was melted"
cie messed up
Post by: Vin on May 21, 2010, 05:53:50 pm
I misread the question, that's all.
Oh im sorry, i didnt see ur reply ;)
Post by: ambitious94 on May 21, 2010, 05:54:24 pm
heat is gained from the surroundings in the experiment, by measuring for another two minutes, you can work out the effect of heat gained from the surroundings (ice that were melted due to those heat), subtract that from the total amount of ice melted will get you the full amount of ice melted due to the energy supplied by the heater.But isn't it somewhat illogical. I mean isn't some of the heat from the heater still not present in the ice? It could be acting too. :S Anyways, thanks for all the help, all of u, it's helped me a lot! ;D
Post by: ambitious94 on May 21, 2010, 05:55:12 pm
yeah but it saysi totally agree with u :) XD
"16.3g of ice was melted in 2 minutes USING THE HEATER."
and "FURTHER 2.1g was melted"
cie messed up
Post by: WARRIOR on May 21, 2010, 05:55:26 pm
I misread the question, that's all.well then my mistake
can u explain why into out of paper????
With L.H. rule the connvectional current goes upwards..so electron should go downwards shouldnt it??
FIELD IS DOWN FIRST FINGER ( POINTING TOWRDS ME )
SECOND ( TO THE RIGHT )
THUMB IS UP
whats wrong?
Post by: Fastal on May 21, 2010, 05:57:17 pm
heat is gained from the surroundings in the experiment, by measuring for another two minutes, you can work out the effect of heat gained from the surroundings (ice that were melted due to those heat), subtract that from the total amount of ice melted will get you the full amount of ice melted due to the energy supplied by the heater.
Specific latent heat of fusion = ML
40 x 120 = (16.3 - 2.1) L
L = 338 J / g
n = sin i / sin r (from rarer to denser medium. if it is from denser to rarer medium, such as glass to air, then take the reciprocal, sin r / sin i)
OHICOMPLETELYUNDERSTAD,
THANKYOU
+rep
Post by: Fastal on May 21, 2010, 05:58:14 pm
i totally agree with u :) XD
read post#875
cie didnt mess up lol
Post by: Vin on May 21, 2010, 05:59:12 pm
Post by: Vin on May 21, 2010, 06:00:44 pm
Q = mL
power is nothing but Joules per second
heat (Q) = 40 J/sec * 120 sec
Q = 4800 J
mass = 16.3-2.1 = 14.2
as the mass melted by the heater is only till 2.1g
4800 = 14.2 * L
L= 338 J/g
lemme check the other ques
ALWAYS formula for refractive index depends from which medium it passes
eg .
From denser to rarer (glass to air) = sin r /sin i
From rarer to denser (air to glass = sin i / sin r
here its(glass to air) = sin r /sin i
sin r/sin 30 = 1.49
sin r = sin (30) * 1.49
r = sin-1(0.745)
=48.2 o
i believe i explained it even before ::) ::) jk doesnt matter who explained before .. glad u got it ;)
Post by: Fastal on May 21, 2010, 06:02:31 pm
i believe i explained it even before ::) ::) jk doesnt matter who explained before .. glad u got it ;)
yeah but what Darren said maid more sense(sorry)
Post by: WARRIOR on May 21, 2010, 06:04:42 pm
i believe i explained it even before ::) ::) jk doesnt matter who explained before .. glad u got it ;)well then my mistake
can u explain why into out of paper?Huh?
With L.H. rule the connvectional current goes upwards..so electron should go downwards shouldnt it??
FIELD IS DOWN FIRST FINGER ( POINTING TOWRDS ME )
SECOND ( TO THE RIGHT )
THUMB IS UP
whats wrong?
for the october question please explain !
Post by: The Golden Girl =D on May 21, 2010, 06:06:07 pm
i believe i should mainly concentrate on memorizing the notes very well ,and i think that past papers r not a necessity as practsing for paper 6 , u kno what i mean
so what do u suggest? ....answer ASAP plz
Post by: Vin on May 21, 2010, 06:07:33 pm
well then my mistake
can u explain why into out of paper?Huh?
With L.H. rule the connvectional current goes upwards..so electron should go downwards shouldnt it??
FIELD IS DOWN FIRST FINGER ( POINTING TOWRDS ME )
SECOND ( TO THE RIGHT )
THUMB IS UP
whats wrong?
for the october question please explain !
Use this interactive site .. keep pressing space to get further explanation .. still u didnt get it ask ..
http://www.furryelephant.com/content/radioactivity/discovery-radioactivity-nucleus/flemings-left-hand-rule-alpha-beta/
Post by: WARRIOR on May 21, 2010, 06:08:22 pm
poeple how should i study for paper 3 physicswell defintly go over the notes first but past papers are as important as notes ! but go over all the notes first ..shouldnt take much ! then enjoy owning past papers
i believe i should mainly concentrate on memorizing the notes very well ,and i think that past papers r not a necessity as practsing for paper 6 , u kno what i mean
so what do u suggest? ....answer ASAP plz
PS; SOME1 ASNWER MY QEUSTION?
Post by: J.Darren on May 21, 2010, 06:10:44 pm
well then my mistakeYou flip the direction of the finger that represent the current.
can u explain why into out of paper?Huh?
With L.H. rule the connvectional current goes upwards..so electron should go downwards shouldnt it??
FIELD IS DOWN FIRST FINGER ( POINTING TOWRDS ME )
SECOND ( TO THE RIGHT )
THUMB IS UP
whats wrong?
for the october question please explain !
In the case for beta particle
The finger : To the left.
Index finger : Towards you.
Thumb : Downwards.
Post by: J.Darren on May 21, 2010, 06:11:30 pm
well defintly go over the notes first but past papers are as important as notes ! but go over all the notes first ..shouldnt take much ! then enjoy owning past papersI think for Physics it is vital to understand the concepts, even more so compared to the other subjects ...
PS; SOME1 ASNWER MY QEUSTION?
Post by: Vin on May 21, 2010, 06:13:07 pm
poeple how should i study for paper 3 physics
i believe i should mainly concentrate on memorizing the notes very well ,and i think that past papers r not a necessity as practsing for paper 6 , u kno what i mean
so what do u suggest? ....answer ASAP plz
paper 6 or 3 ??
for physics, yes study your notes very well .. also solve as many ques as possible from past papers or ur text book .. i took 2 days to do tht before my mock.. each and every question in the book and never did any past papers and got A* in the mock .. i was really benefited tht time .. i was SO freaking lacking behind in physics !! now im solving solely past papers.. also i'll study notes before the day of the exam
BEST OF LUCK !! :D :D
Post by: The Golden Girl =D on May 21, 2010, 06:15:55 pm
paper 6 or 3 ??
for physics, yes study your notes very well .. also solve as many ques as possible from past papers or ur text book .. i took 2 days to do tht before my mock.. each and every question in the book and never did any past papers and got A* in the mock .. i was really benefited tht time .. i was SO freaking lacking behind in physics !! now im solving solely past papers.. also i'll study notes before the day of the exam
BEST OF LUCK !! :D :D
thx alot
Post by: WARRIOR on May 21, 2010, 06:17:13 pm
You flip the direction of the finger that represent the current.since thumb is downwoards does the mean beta particles are downwards or convection current wire moves downwards?
In the case for beta particle
The finger : To the left.
Index finger : Towards you.
Thumb : Downwards.
Post by: Vin on May 21, 2010, 06:20:39 pm
since thumb is downwoards does the mean beta particles are downwards or convection current wire moves downwards?
ALPHA PARTICLES ARE +VE SO THEY MOVE LIKE CONVENTIONAL CURRENT .. i.e. THEY MOVE IN THE DIRECTION OF WHICH U POINT
BETA ARE -VE CHARGES SO THEY MOVE IN THE OPPOSITE DIRECTION .. THEY ARE MOST DEFLECTED BY THE MAGNETIC FIELD
Post by: WARRIOR on May 21, 2010, 06:25:44 pm
ALPHA PARTICLES ARE +VE SO THEY MOVE LIKE CONVENTIONAL CURRENT .. i.e. THEY MOVE IN THE DIRECTION OF WHICH U POINTthat means they should move into the page?
BETA ARE -VE CHARGES SO THEY MOVE IN THE OPPOSITE DIRECTION .. THEY ARE MOST DEFLECTED BY THE MAGNETIC FIELD
my thumb pointed up when i used convecitonal current..so now it should point down with ebta particles?
Post by: J.Darren on May 21, 2010, 06:28:49 pm
that means they should move into the page?Ditto. In the case for beta particle, reverse the direction of the current. Equally, the thumb should be pointing upside down if that is the case as the direction of the magnetic field remains unchanged.
my thumb pointed up when i used convecitonal current..so now it should point down with ebta particles?
Post by: WARRIOR on May 21, 2010, 06:37:55 pm
Ditto. In the case for beta particle, reverse the direction of the current. Equally, the thumb should be pointing upside down if that is the case as the direction of the magnetic field remains unchanged.looooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooool :O
im moving teh position of my finger :/ i didnt twist my hand to get the direction !!!!! looool i was jst changin position of my figners lool what an idiot !!!!!! christ !! thanks guys u both saved me big time ! and sorry for makin u go crazy !
Post by: guMnam on May 21, 2010, 06:51:31 pm
looooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooool :Ohmm it happens sumtimes wen u study too much ;)
im moving teh position of my finger :/ i didnt twist my hand to get the direction !!!!! looool i was jst changin position of my figners lool what an idiot !!!!!! christ !! thanks guys u both saved me big time ! and sorry for makin u go crazy !
Post by: WARRIOR on May 22, 2010, 07:27:47 am
Question 8 (A) part 2
why is resistance of lamp 4/.4??? = 10 Ohms..10 Ohms would be resistanc of the whole circuit !! + the coild of wire , or do we pretend that tthe coil of wire doesnt have resistance?? ( but then in part (B) it tells you the wire has resistance hmm)?? ???
Why dont we use 1.5 / .4??
Thanks in advanced!
Post by: holtadit on May 22, 2010, 07:34:02 am
There is low heat on the thermistor.
SO Its resistance RISES
P.D. across thermistor RISES
As the Resistance of R1 is LESS THAN the resistance of the THERMISTOR the Voltage output to the Transistor is LARGER than 0.6V.
So the transistor switches on and the lamp lights.
-------------------------------------------------------------------------------------------------------------------------------------
Would this get me 3 marks ? Is the explanation correct ? Its from summer 2007 paper 3 Question 10
Post by: WARRIOR on May 22, 2010, 07:46:53 am
Okay.MOST PROBABLY YEAH..
There is low heat on the thermistor.
SO Its resistance RISES
P.D. across thermistor RISES
As the Resistance of R1 is LESS THAN the resistance of the THERMISTOR the Voltage output to the Transistor is LARGER than 0.6V.
So the transistor switches on and the lamp lights.
-------------------------------------------------------------------------------------------------------------------------------------
Would this get me 3 marks ? Is the explanation correct ? Its from summer 2007 paper 3 Question 10
my teachers explanation waas :
Heat decreases the resistance of thermistor. The voltage accrose base and emittor is enough to swicht on the transistor and lamp lights
hmm it doesnt tell you high or low temperature so you choose whatver u want
Post by: holtadit on May 22, 2010, 07:52:58 am
Anyone with a DEFINITE answer as to whether my above answer is correct/wrong.
Post by: guMnam on May 22, 2010, 08:04:42 am
Okay.i dont effing get it....c the thing needed to switch on the transistor is...tht one of the resistors in the potenial divider has to be more and the other has to be less than tht of the pd of the circuit??? is it like tht ???
There is low heat on the thermistor.
SO Its resistance RISES
P.D. across thermistor RISES
As the Resistance of R1 is LESS THAN the resistance of the THERMISTOR the Voltage output to the Transistor is LARGER than 0.6V.
So the transistor switches on and the lamp lights.
-------------------------------------------------------------------------------------------------------------------------------------
Would this get me 3 marks ? Is the explanation correct ? Its from summer 2007 paper 3 Question 10
Post by: Fastal on May 22, 2010, 08:10:35 am
i dont effing get it....c the thing needed to switch on the resistor is...tht one of the resistors in the potenial divider has to be more and the other has to be less than tht of the pd of the circuit??? is it like tht ???
i dont understand this either.
Post by: NidZ- Hero on May 22, 2010, 08:38:25 am
Post by: WARRIOR on May 22, 2010, 08:42:12 am
i dont effing get it....c the thing needed to switch on the transistor is...tht one of the resistors in the potenial divider has to be more and the other has to be less than tht of the pd of the circuit??? is it like tht ???
My teacher was a examiner and used to correct exams of igcse . she told me to rwright this any time it comes up ( transistor ) no matter The reading resistance of LDR or thermister you say the following ( if its increase right increase if its dec right dec )
in this case an LDR WITH LIGHT . ( and it says the bulb switches on )
So light decreases ristance of thermistor . Voltage acros base and emimitor is high enough to swtich transistor on and bulb lights
another case:
thermistort without heat . ( and it says fire alarm is off )
so thermistor has high resistance , voltage acrose base and emmitor is nto hight enough to switch transistor on and bulb doesnt light
get my point?
Post by: guMnam on May 22, 2010, 08:44:15 am
can any one help me wid 2004 m/j p3 phy Q2 (c) can ny one tell me wats de rght answer 4 this :)answer thanzed?:pthe kinetic energy of the rok decreases...some of it is transformed into sound of splash...sum of it makes the water move ..and some of it is still there ans it is sink in the water..:D
Post by: holtadit on May 22, 2010, 08:44:44 am
can any one help me wid 2004 m/j p3 phy Q2 (c) can ny one tell me wats de rght answer 4 this :)answer thanzed?:p
Okay when you drop a rock in water what happens ? You HEAR a splash. So sound energy is one answer.
Next, all energy EVENTUALLY lands up as HEAT. SO ALWAYS write heat energy. That should be enough for 2 marks. ;)
You remind me of Nid. :P
Post by: guMnam on May 22, 2010, 08:56:27 am
My teacher was a examiner and used to correct exams of igcse . she told me to rwright this any time it comes up ( transistor ) no matter The reading resistance of LDR or thermister you say the following ( if its increase right increase if its dec right dec )yea i get tht part the only thing i dont uderstand is the relation between th two resistor..one of the is thermistor in our case...yea just fill in this for me.. in order to turn on the transistor the resistance of the thermistor should be______ and the resistance of the2nd resistor is ________. this makes the voltage across the base and emitor high enough to turn the transistor on..options ...high and low
in this case an LDR WITH LIGHT . ( and it says the bulb switches on )
So light decreases ristance of thermistor . Voltage acros base and emimitor is high enough to swtich transistor on and bulb lights
another case:
thermistort without heat . ( and it says fire alarm is off )
so thermistor has high resistance , voltage acrose base and emmitor is nto hight enough to switch transistor on and bulb doesnt light
get my point?
Post by: WARRIOR on May 22, 2010, 09:08:09 am
yea i get tht part the only thing i dont uderstand is the relation between th two resistor..one of the is thermistor in our case...yea just fill in this for me.. in order to turn on the transistor the resistance of the thermistor should be______ and the resistance of the2nd resistor is ________. this makes the voltage across the base and emitor high enough to turn the transistor on..options ...high and lowit doesnt matter what it is..if the resistance of thermister r or high or low it doesnt matter. as logn as bulb is on ...that means there is enough voltage . and the resistance of teh second resstance does not affect anythign !! unless if tehre is a variable resistor !!
check may june 2007 question 10 ..varible resistor part
man im gonna stop advising you about this topic caz i dunno anythin about it i jsut learnt it by heart!
Post by: guMnam on May 22, 2010, 09:14:09 am
it doesnt matter what it is..if the resistance of thermister r or high or low it doesnt matter. as logn as bulb is on ...that means there is enough voltage . and the resistance of teh second resstance does not affect anythign !! unless if tehre is a variable resistor !!hmmm....okay can u tell me if in a series combined resistance of two resister is...r1+r2.....yani if r1 is 2o and r2 is 1o..the combined resistance would be 3..or 1
check may june 2007 question 10 ..varible resistor part
man im gonna stop advising you about this topic caz i dunno anythin about it i jsut learnt it by heart!
Post by: holtadit on May 22, 2010, 09:18:19 am
Click on it to enlarge.
Post by: WARRIOR on May 22, 2010, 09:23:43 am
hmmm....okay can u tell me if in a series combined resistance of two resister is...r1+r2.....yani if r1 is 2o and r2 is 1o..the combined resistance would be 3..or 1
3...in series you jsut add up all teh resistance
in parallel you always use the formula 1/tot. resitace = 1/r + 1/r and then invert the asnwer !
for example if resitos in apralel were 3 and 5
1/3 + 1/5 = 1/r
asnwer will be 15/8 ( invert ) and so 1.875 is the total resistance
Post by: WARRIOR on May 22, 2010, 09:25:33 am
See the picture.caz when the water is being pumped up ! there is friction between the walls and water and so some energy will be lost and therrfore you need more kinetic enrgy to pump uup the water ( TO COMPENSATE FOR THE LOST ENERGY )
Click on it to enlarge.
Post by: NidZ- Hero on May 22, 2010, 09:27:29 am
Okay when you drop a rock in water what happens ? You HEAR a splash. So sound energy is one answer.oye but its 4 3 marks :)
Next, all energy EVENTUALLY lands up as HEAT. SO ALWAYS write heat energy. That should be enough for 2 marks. ;)
You remind me of Nid. :P
Post by: holtadit on May 22, 2010, 09:32:14 am
oye but its 4 3 marks :)
I suggest reading the MS. ;)
Post by: NidZ- Hero on May 22, 2010, 09:36:15 am
I suggest reading the MS. ;)gosh markin scheme its lke learnin de answer wats de use wen u dont understand anywasy thanz i vil read de ms
Post by: WARRIOR on May 22, 2010, 09:53:59 am
Question 8 (A) part 2
why is resistance of lamp 4/.4??? = 10 Ohms..10 Ohms would be resistanc of the whole circuit !! + the coild of wire , or do we pretend that tthe coil of wire doesnt have resistance?? ( but then in part (B) it tells you the wire has resistance hmm)?? Huh?
Why dont we use 1.5 / .4??
Thanks in advanced!
Post by: Vin on May 22, 2010, 09:57:20 am
May june 2001
Question 8 (A) part 2
why is resistance of lamp 4/.4??? = 10 Ohms..10 Ohms would be resistanc of the whole circuit !! + the coild of wire , or do we pretend that tthe coil of wire doesnt have resistance?? ( but then in part (B) it tells you the wire has resistance hmm)?? Huh?
Why dont we use 1.5 / .4??
Thanks in advanced!
can u pls. post the paper ?? i dont seem to find it =|
Post by: WARRIOR on May 22, 2010, 10:00:00 am
can u pls. post the paper ?? i dont seem to find it =|http://www.freeexampapers.com/Dndex.php?d=SUdDU0UvUGh5c2ljcy9DSUUvMTk5MyAtIDIwMDM=
ur gonna have to downlaod 1993-2002 :/
u dont have it on paper ?
Post by: Baladya on May 22, 2010, 10:13:05 am
32) why is the answer B?? This is what my book says: "When in the first step, the switch i closed, current flows into the capacitor as shown. A resistor R should be fitted to prevent too strong a surge of current. Initially, the p.d across the capacitor is 0 V, and the full 12 V is across the resistor
Thanks ;)
Post by: holtadit on May 22, 2010, 10:16:34 am
operator’s hand. The spark is a very hot, very small piece of metal. The operator feels nothing.
What does this show about the piece of metal?
A It has a high thermal capacity.
B It has a low thermal capacity.
C It is a good conductor of heat.
D It is a poor conductor of heat.
Post by: Baladya on May 22, 2010, 10:19:41 am
15) A knife is being sharpened on a rotating sharpening-stone. A spark flies off and lands on the
operator’s hand. The spark is a very hot, very small piece of metal. The operator feels nothing.
What does this show about the piece of metal?
A It has a high thermal capacity.
B It has a low thermal capacity.
C It is a good conductor of heat.
D It is a poor conductor of heat.
B. Its because it has such a low thermal capacity that when it flies, in no time it loses its heat and becomes cold
Post by: WARRIOR on May 22, 2010, 10:21:36 am
http://www.freeexampapers.us/IGCSE/Physics/CIE/2007%20Nov/0625_w07_qp_1.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2007%20Nov/0625_w07_qp_1.pdf)dont get what are you ssaying
32) why is the answer B?? This is what my book says: "When in the first step, the switch i closed, current flows into the capacitor as shown. A resistor R should be fitted to prevent too strong a surge of current. Initially, the p.d across the capacitor is 0 V, and the full 12 V is across the resistor
Thanks ;)
Look for the voltage aroudn teh battery is obviously 12V
And for teh capacitator it will be 12..because you close the switch teh capacitatore becomes charged till it becomes 12v now when you open the switch . The capacitator will be 12V and ready to dissipate its voltage any time .
Resistor has no resistance unless a current passes through it , so how willi t have voltage???
Post by: holtadit on May 22, 2010, 10:22:52 am
B. Its because it has such a low thermal capacity that when it flies, in no time it loses its heat and becomes cold
+rep.
Could you also explain EVERYTHING I need to know about thermal capacity since my book is a bit bare; and its the only topic I have problems in.
Much appreciated man. :)
Post by: Vin on May 22, 2010, 10:23:30 am
May june 2001
Question 8 (A) part 2
why is resistance of lamp 4/.4??? = 10 Ohms..10 Ohms would be resistanc of the whole circuit !! + the coild of wire , or do we pretend that tthe coil of wire doesnt have resistance?? ( but then in part (B) it tells you the wire has resistance hmm)?? Huh?
Why dont we use 1.5 / .4??
Thanks in advanced!
thts because no matter the lamp is marked 1.5 V the p.d applied is 4 V so the current take from the battery has to be according to the pd of battery and not the lamp
Post by: WARRIOR on May 22, 2010, 10:31:17 am
thts because no matter the lamp is marked 1.5 V the p.d applied is 4 V so the current take from the battery has to be according to the pd of battery and not the lampwell that means there are no other resistors in teh circuit..because the whole 4v isgoin to the lamp right??
Post by: WARRIOR on May 22, 2010, 10:32:43 am
+rep.
Could you also explain EVERYTHING I need to know about thermal capacity since my book is a bit bare; and its the only topic I have problems in.
Much appreciated man. :)
I wrote notes on thermal physics if u want to read..
https://studentforums.biz/index.php/topic,7946.0.html ( scroll down .its in red )
Post by: holtadit on May 22, 2010, 10:41:54 am
Post by: Vin on May 22, 2010, 10:43:24 am
well that means there are no other resistors in teh circuit..because the whole 4v isgoin to the lamp right??
the ques means means that wen a p.d of 4V is provided to the lamp wat is the resistance as the current in the circuit .. after thinking a lot i think it means wat u r saying .. =\
Post by: Baladya on May 22, 2010, 10:47:39 am
+rep.
Could you also explain EVERYTHING I need to know about thermal capacity since my book is a bit bare; and its the only topic I have problems in.
Much appreciated man. :)
Well first of all know that everything expands when heated. And they all contract when cooled. Water however, contracts when cooled until it reaches 4*C then it becomes to expand when cooled more.
There are diff ways to measure temp:
1-Liquid in Glass (alchohol or mercury)
Thermometrs are characterised by Sensitivity: which is that when a small amount of heat is given to a liquid, it expands a lot. In this case alchohol expands more. Another way to make it more sensitive is to make the bulb big and the narrow glass tube
Another characteristic is Range and it means till what temp can the liquids expand without getting boiled or become solid. For example Mercury has a freezing point of -38 so it would be useless in Antartica cuz it will freeze. Alchohol has a boiling point of 78, so its not good for hot places cuz it will boil easily
Linearity is that the thermometer is correctly calibrated. So if the temp increases to 30*C, the thermometer will show exactly 30
Also accuracy, which pretty much depends on linearity, which means that it should show correct temps. (i dont realy no the diff between accuracy and linearity)
Calibration of the thermometer is by putting it in MELTING ice and marking the point of the liquid. Put it in STEAM and mark it. Then divide it to 100 diff marks
2-Thermocouple can be used to measure too... It is small so it can fit into small areas, and cuz its small so its fast. It can read up to 1000*C so its good for industry. Its digital so it can be read on a remote dial...
I can't find a good pic but this is what it consists of : \/ -------------------------- --------------------------------
|
(hot conjunction (the object) V
|
/\ ---------connected to beaker of ice hear) ----------------
Look, the upper wire and the wire under the Voltmeter are made of copper. the one between the ice and hot is made of constantan.
3- Bietallic strip can measure temp too but u just have to know that it is used in stuff like iron (for clothes). What happens is that when u connected to power, two stripes gets heated, as they get more heated on of them expands more and breaks contact, and so 'cut' a circuit and the heating element stops getting current and just stop :P
I will tell you more but just lemme study for some time xD :D
Edit:
Now we will discuss Thermal Capacity:
Thermal Capacity is the amount of heat needed to heat up an object. SPECIFIC heat capacity is: The amount of heat needed to RAISE THE TEMP OF 1 KG OF THE OBJECT BY 1*C.
Experiment for heat capacity:
- For a blockk of metal : A block of metal with a heater in and a thermometer (there is gaps in it to fit them). The heater should be connected to a voltmeter and an ammeter. Put insulation, bla bla... Now record the initial temp and final temp, and record the total time THE HEATER WAS ON. Now just apply the rule c=E/(m*(t2-t1)).
C is the specufic heat capacity, m=mass, t2=final temp, t1=initial. Remember that E(energy) can be calculated like this(very imp): E=VxIxT
So We have Voltage and Current (from voltmeter and ammeter on heater) and we know the total time the heater was on. Multiply them to get E. then just apply the rule...
MELTING AND BOILING:
(http://www.antonine-education.co.uk/New_items/Gateway/p1_energy_for_the_home_files/image001.gif)
So WTF is that... Lemme tell you. As u can see and as u know that when u give smth energy, it becomes hotter, which is exactly what happening in the first line. However the second line shows no change in temp tho we are still giving energy!! WHY? In the first part the energy given was used to make the particles vibrate more... However now that the MELTING POINT is reached, the energy is instead used to loosen the bond between the atoms. Remember, vibrations mean more temp but here its used to loosen the bonds not to add vibrations. Also u have to know that when its used for vibrations it is KINETIC ENERGY, but when its used to loosen the bonds its POTENTIAL ENERGY. Also, the part where the temp is constant shows melting, so there will be BOTH solid and liquid (its still melting). However when it reaches the point where the graph starts to climb again, all the solid is liquid now.
Again the same thing in th beggining happens now, the temp is rising until it reaches boiling point where the energy is instead... bla bla
So, what is this energy called and what is its formula? That my friend willl be in the next episode... (jk xD I will tell u after lunch ;D)
Edit:
The extra energy stored by the water at 0*C, as opposed to ice at 0*C, is the LATENT HEAT OF FUSION
This is they summary of what i explained above!!
The heat required to melt a unit mass of solid, and turned it into liquid is known as the SPECIFIC latent heat of fusion of that solid (symbol L) and is measured in J/Kg or J/g
For gases its called Latent heat of vaporisation
Experiment about Latent Heat:
1-Latent Heat of Fusion of Ice:
a-Weight a beaker without the heater.
b-Dry the ice on a cloth and put into beaker
c-switch heater, start stopwatch
d-stir
e-measure the time taken for the ice to melt
f-weight the beaker plus the water
Very important to know that the FORMULA OF LATENT HEAT IS: L=E/m
this is a bit similar to the previous experiment, all u gotta do is calculate E by VxIxt then divide by m (which is mass of beaker and water - mass of beaker)
2-Latent Heat of Vapourisation of Water:
a- water in beaker
b-weight water+beaker
c-switch on heater
d-WHEN THE WATER BOILS, start the stopwatch and let the water boil for a few minutes
e-weight again
last weight-initial =m and u know the rest......
WATER:
A couple of things u need to know is as i said how it expands below 4C, and that water has a very hight specific heat capacity. This makes it an excelent coolant for machines, bla bla. And this is what makes the temperature of seas and oceans temperature almost steady as they need enormous energy just to increase a couple of degrees.
There is a confusion around the word steam. Steam is colourless and its at 100C. It occurs when u are boiling water in a kettle. THIS IS EXTREMEMLY DANGEROUS. However in a short time it condenses and turn into water droplets which form the whit clouds u see (and u think its steam but its not).
Last thing is bioling is at BIOLING temperature only and molecules from every part of the liquid vapourises (every part means the particles on top and bottom).
Evapouration however happen at any temperature simultaneously and only the particles on the surface vapourise (cuz only these particles have ENOUGH energy to escape)
HOPE THIS HELPS :D ;) :) ;D
Baladya
Post by: WARRIOR on May 22, 2010, 10:48:32 am
the ques means means that wen a p.d of 4V is provided to the lamp wat is the resistance as the current in the circuit .. after thinking a lot i think it means wat u r saying .. =\
lol ok ! man i used to find electricty way easier whn i studied less and i used to get asnwer right! now that i become precise about evrything i make mistakes..
ill send you one of the harder circuit questions later !
Post by: Baladya on May 22, 2010, 10:50:47 am
dont get what are you ssaying
Look for the voltage aroudn teh battery is obviously 12V
And for teh capacitator it will be 12..because you close the switch teh capacitatore becomes charged till it becomes 12v now when you open the switch . The capacitator will be 12V and ready to dissipate its voltage any time .
Resistor has no resistance unless a current passes through it , so how willi t have voltage???
Lol i read the question wrong :P Thx very much :)
Post by: $H00t!N& $t@r on May 22, 2010, 11:07:23 am
how can the output be electrical???
Post by: Vin on May 22, 2010, 11:16:20 am
p1 2009 o/n question 10
how can the output be electrical???
its asked IN the microphone .. sound energy (while the person speaks) in converted to electrical energy .. y ?? because the microphone has to send the "information" to the through the WIRES .. they can carry ony electrical energy .. to the speaker .. then elec to sound takes place in a loud speaker ..
Post by: Baladya on May 22, 2010, 11:20:00 am
p1 2009 o/n question 10
how can the output be electrical???
This is the same as LDR and the thermistor. They receive analoge stuff like sound, heat, light (stuff we can sense) and convert it into electricity. Here it is converted to electricity so it can be modified, and becomes sound again (later) but louder
Post by: $H00t!N& $t@r on May 22, 2010, 11:21:21 am
Post by: Vin on May 22, 2010, 11:31:21 am
This is the same as LDR and the thermistor. They receive analoge stuff like sound, heat, light (stuff we can sense) and convert it into electricity. Here it is converted to electricity so it can be modified, and becomes sound again (later) but louder
ohhhhh IN THE MICROPHONE i dint see that part Thanks ;D
yup they are called transducers .. ;)
Post by: WARRIOR on May 22, 2010, 12:02:19 pm
QUESTION 3 ( A)
Post by: Vin on May 22, 2010, 12:15:43 pm
Winter 1999
QUESTION 3 ( A)
is it 160 ??
Post by: SoONa on May 22, 2010, 12:33:42 pm
it really confuses me .. thanks in advance and goodluck all hope we rock the exam ;D
Post by: WARRIOR on May 22, 2010, 12:46:50 pm
is it 160 ??
yeaah how did u calcualte that?? u extended it ?
Post by: Vin on May 22, 2010, 12:53:39 pm
see in this image when the switch is turned on the circuit gets completed and the soft iron core gets magnetised. the soft iron armature gets attracted to the core and the bell rings once .. *ting* ..notice that the "contacts" looses contact with the spring and the circuit is broken and the iron is demagnetised and the armature returns back to its original position as shown in the pic. notice the circuit is complete again and this cycle continues .. if u might hav heard a bell in school u get multiple *tings* so rapidly !! this is wat all happens again n again at such high frequency .. ;)
BEST OF LUCK !! :D :D
Post by: WARRIOR on May 22, 2010, 12:55:43 pm
(http://media.tiscali.co.uk/images/feeds/hutchinson/ency/0008n094.jpg)yeaah how did u calcualte that?? u extended it ?
see in this image when the switch is turned on the circuit gets completed and the soft iron core gets magnetised. the soft iron armature gets attracted to the core and the bell rings once .. *ting* ..notice that the "contacts" looses contact with the spring and the circuit is broken and the iron is demagnetised and the armature returns back to its original position as shown in the pic. notice the circuit is complete again and this cycle continues .. if u might hav heard a bell in school u get multiple *tings* so rapidly !! this is wat all happens again n again at such high frequency .. ;)
BEST OF LUCK !! :D :D
Post by: Baladya on May 22, 2010, 01:27:23 pm
27) u guys told me that plotting compasses always point to North. Well i chose A, but its B... WHY? Plz explain clearly :S
Post by: Vin on May 22, 2010, 01:33:08 pm
yeaah how did u calcualte that?? u extended it ?
wats given in the ms ?? i got it by fluke .. now im getting 170 ?? anything given in the ms ??
Post by: WARRIOR on May 22, 2010, 01:34:55 pm
http://www.freeexampapers.us/IGCSE/Physics/CIE/2007%20Jun/0625_s07_qp_1.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2007%20Jun/0625_s07_qp_1.pdf)
27) u guys told me that plotting compasses always point to North. Well i chose A, but its B... WHY? Plz explain clearly :S
http://www.scienceteacherprogram.org/physics/Omoloju04_files/image002.jpg
magnetic field is from north to south
the compass north follows the magnetic field.
Post by: WARRIOR on May 22, 2010, 01:35:50 pm
wats given in the ms ?? i got it by fluke .. now im getting 170 ?? anything given in the ms ??
160 in mark scheme
how?? daymn..i thik u jsut extend it and measure the angle?
Post by: Vin on May 22, 2010, 01:37:25 pm
160 in mark scheme
how?? daymn..i thik u jsut extend it and measure the angle?
try doing tht .. u get 160 ??
Post by: Vin on May 22, 2010, 01:38:04 pm
http://www.freeexampapers.us/IGCSE/Physics/CIE/2007%20Jun/0625_s07_qp_1.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2007%20Jun/0625_s07_qp_1.pdf)
27) u guys told me that plotting compasses always point to North. Well i chose A, but its B... WHY? Plz explain clearly :S
dude always the back of the magnet points at North
Post by: Vin on May 22, 2010, 01:39:00 pm
160 in mark scheme
how?? daymn..i thik u jsut extend it and measure the angle?
u got it .. im getting 170
Post by: Baladya on May 22, 2010, 01:41:48 pm
dude always the back of the magnet points at North
OMG THOSE NOOBS >:D I knew it was like that but some noobs told me its the other way -.- 0.0
Anyway thx Kimo and Vin :)
Post by: Malak on May 22, 2010, 05:19:39 pm
(Second variant)
Q4: Part a (all)
Q7: part b
Q10: part c.. Is there a different formula to calculate R...I used 1/R + 1/R?
Thx
Post by: Vin on May 22, 2010, 05:30:45 pm
7) b) ok molecules with high energy evaporate, when water evaporates it takes the heat energy with it .. i.e. heat is required to evaporate the water so this heat is "taken" from the milk this is the after effect of water evaporation.. also the cloth soaks up water constantly.
10 ) c) 1/R1 + 1/R2 is the one
also there is another one R1 × R2 / R1 + R2
Post by: WARRIOR on May 22, 2010, 05:34:43 pm
http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Jun/0625_s09_qp_3.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Jun/0625_s09_qp_3.pdf)first questioni cant explain 4 caz i have to draw it :
(Second variant)
Q4: Part a (all)
Q7: part b
Q10: part c.. Is there a different formula to calculate R...I used 1/R + 1/R?
Thx
This is becaus of evaporation ( remember occurs at any temperature ) ! we all know evaportation causes cooling ! so now the the cloth is damp by water at room temperature !!! water molecules on cloth with most kinetic enrgy will escape adn brake bonds from other water molecules. This leaves the molecules with least K.e in the cloth !!! So avergae KE is less and so the temperuter decrease!
and lastly the resitors I DUNNO ABOUT ANY OTHER FORUMLA but i used 1/r + 1/r and it was fine
Post by: Ghost Of Highbury on May 22, 2010, 05:37:44 pm
http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Jun/0625_s09_qp_3.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Jun/0625_s09_qp_3.pdf)
(Second variant)
Q4: Part a (all)
Q7: part b
Q10: part c.. Is there a different formula to calculate R...I used 1/R + 1/R?
Thx
draw the scale diagram as shown
1cm = 500N
4000N(A) = 8cm
2000N(B) = 4cm
draw the parallelogram ..the diagonal is the resultant force..11cm shud be the diagonal's length.
11cm = 500*11 = 5500N ..
measure the length of the diagonal and calculate the force accordingly
measure the angle
shud be
-> 5500N
--> 30o
Post by: Malak on May 22, 2010, 05:44:04 pm
first questioni cant explain 4 caz i have to draw it :
This is becaus of evaporation ( remember occurs at any temperature ) ! we all know evaportation causes cooling ! so now the the cloth is damp by water at room temperature !!! water molecules on cloth with most kinetic enrgy will escape adn brake bonds from other water molecules. This leaves the molecules with least K.e in the cloth !!! So avergae KE is less and so the temperuter decrease!
and lastly the resitors I DUNNO ABOUT ANY OTHER FORUMLA but i used 1/r + 1/r and it was fine
And wat was ur answer?...Wat values did u use for r..? cuz m gettin a wrng answer ???
N thx all for answering :)
Post by: WARRIOR on May 22, 2010, 05:47:03 pm
And wat was ur answer?...Wat values did u use for r..? cuz m gettin a wrng answer ???
N thx all for answering :)
The asnwer should be 5.33 A
u add them up..it will be 3/16 then u take the inverse of it which is 16/3 and then divide
remember the form is 1/R ( TOTAL RESISTN ) = 1/8 + 1/16
so you have to switch 1/R to be R
Post by: Ghost Of Highbury on May 22, 2010, 05:50:23 pm
The asnwer should be 5.33 A
u add them up..it will be 3/16 then u take the inverse of it which is 16/3 and then divide
remember the form is 1/R ( TOTAL RESISTN ) = 1/8 + 1/16
so you have to switch 1/R to be R
shud be 2.25 Amperes, not 5.33 Amperes.
1/R = 3/16
R = 16/3 = 5.33ohms
V = IR
12 = I*5.33
I = 12/5.33
= 2.25 A
4aii) attached
Post by: WARRIOR on May 22, 2010, 05:52:17 pm
shud be 2.25 Amperes, not 5.22 Amperes.i meant 5.33 ohms :P
5.33 ohms..12/5.33 = 2.25 A
oops i forgo to 2calulate Amps
Post by: Malak on May 22, 2010, 06:02:17 pm
in MS it say 0.9?
Post by: Ghost Of Highbury on May 22, 2010, 06:05:49 pm
Where did u guys got the 3 and 16 from..? ??? confused
N we are calculationg resistance ryt? not current?
ci) 1/1.8 + 1/1.8 = 1.111...1/1.11 = 0.9
ii) When in parallel, they both will receive 12V...however, the lamp are deigned to work at 6V supplu/ they may get damaged due to overheating..
Post by: J.Darren on May 22, 2010, 06:08:26 pm
http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Jun/0625_s09_qp_3.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Jun/0625_s09_qp_3.pdf)7 b)
(Second variant)
Q4: Part a (all)
Q7: part b
Q10: part c.. Is there a different formula to calculate R...I used 1/R + 1/R?
Thx
- water molecules from the bowl gets evaporated
- it condenses on the cloth, making it damp
- the hot air evaporates the water vapours on the damp cloth covering the milk bottle instead of the milk
- the milk bottle is kept cool as it is not evaporated / does not turn bad as it gets heated up
10 c) 1/1.8 + 1/1.8 = 1/R
Post by: J.Darren on May 22, 2010, 06:09:29 pm
read the question , u gotta calculate the current.I think ang3l is referring to the second variant :D
V = I*R
R = V/I
THe combined resistance of the two resistors(8 ohms and 16ohms) supposed to be arranged in parallel are
1/R = 1/8 + 1/16
therefore, 1/R = 3/16
R = 16/3 = 5.33ohms
R = 5.33
V = 12
thus I = V/R = 12/5.33 = 2.25A
Post by: J.Darren on May 22, 2010, 06:11:35 pm
Post by: Ghost Of Highbury on May 22, 2010, 06:14:40 pm
I think ang3l is referring to the second variant :D
OOPS!
Post by: Malak on May 22, 2010, 06:17:38 pm
M like...Wat question are they answering to...lmao...
Post by: Malak on May 22, 2010, 06:19:05 pm
7 b)
- water molecules from the bowl gets evaporated
- it condenses on the cloth, making it damp
- the hot air evaporates the water vapours on the damp cloth covering the milk bottle instead of the milk
- the milk bottle is kept cool as it is not evaporated / does not turn bad as it gets heated up
10 c) 1/1.8 + 1/1.8 = 1/R
Yeah i did that...and my answer is 1.111.. in ms its 0.9 ?
Post by: WARRIOR on May 22, 2010, 06:21:26 pm
Yeah i did that...and my answer is 1.111.. in ms its 0.9 ?
dont leave it like that
you have to find the inverse!
do 1/1.11
CAZ ITS 1/R = 1.111
SO WE MAKE R=1/1.11
Post by: Malak on May 22, 2010, 06:25:19 pm
dont leave it like that
you have to find the inverse!
do 1/1.11
CAZ ITS 1/R = 1.111
SO WE MAKE R=1/1.11
Ohkey....Thx :D
Post by: Adzel on May 22, 2010, 06:37:40 pm
Last Q Part (a), (b) and (c) + elplaination please...
as for attached...which one is right and why
Post by: Vin on May 22, 2010, 06:41:20 pm
http://www.xtremepapers.net/CIE/index.php?dir=Cambridge%20IGCSE/0625%20-%20Physics/&file=0625_w02_qp_3.pdf (http://www.xtremepapers.net/CIE/index.php?dir=Cambridge%20IGCSE/0625%20-%20Physics/&file=0625_w02_qp_3.pdf)
Last Q Part (a), (b) and (c) + elplaination please...
as for attached...which one is right and why
for mcq paper its "B"
time taken for HALF the count rate from the original "140" .. half i.e "70" lies between 40 and 60
Q 10 c) after 20 days .. only little part of the original is left ..
d) beta decay is always -1e and +1 proton
AZX ? -1e + AZ+1Y
Post by: J.Darren on May 22, 2010, 06:46:44 pm
for mcq paper its "B"Definition for half-life : Time it takes for a radioactive material to halve its size in a radioactive decay.
time taken for HALF the count rate from the original "140" .. half i.e "70" lies between 40 and 60
Post by: Adzel on May 22, 2010, 07:07:24 pm
Post by: Vin on May 22, 2010, 07:15:31 pm
Thanks VIN...but could you explain more on part (b) please
ok sure .. now wat u do is .. u take the half of "50" (25) and plot a point on 8 because for 50 half life was 4 .. then then half of "25" (12.5) and plot on 16 and extend the curve along these points .. got it ??
Post by: Adzel on May 22, 2010, 07:23:04 pm
then then half of "25" (12.5) and plot on 16 and extend the curve along these points .. got it ??
Why is it on 16?
Post by: Vin on May 22, 2010, 07:38:37 pm
Not yet...this part,
Why is it on 16?
ok u gota kno one thing about half life :: here in this q the half life is 4 days from 100 to 50 right ? so for the count rate to become half (50 to 25)
would be double the time taken ?? forget this .. eg if an isotope of Sodium takes 10 hrs to become half or its half life is 10 hrs .. then a sample of 100
grams would take 10 hrs to become 50g .. further 10 hrs to become 25g further 10 hrs to become 12.5 g .. so apply this logic here ..
dont hesitate to ask if not under stood .. i'll try something else .. ;)
Post by: $H00t!N& $t@r on May 22, 2010, 07:40:38 pm
Post by: NidZ- Hero on May 22, 2010, 07:46:35 pm
Well first of all know that everything expands when heated. And they all contract when cooled. Water however, contracts when cooled until it reaches 4*C then it becomes to expand when cooled more.thanz alot de experiment part is quite help ful :)
There are diff ways to measure temp:
1-Liquid in Glass (alchohol or mercury)
Thermometrs are characterised by Sensitivity: which is that when a small amount of heat is given to a liquid, it expands a lot. In this case alchohol expands more. Another way to make it more sensitive is to make the bulb big and the narrow glass tube
Another characteristic is Range and it means till what temp can the liquids expand without getting boiled or become solid. For example Mercury has a freezing point of -38 so it would be useless in Antartica cuz it will freeze. Alchohol has a boiling point of 78, so its not good for hot places cuz it will boil easily
Linearity is that the thermometer is correctly calibrated. So if the temp increases to 30*C, the thermometer will show exactly 30
Also accuracy, which pretty much depends on linearity, which means that it should show correct temps. (i dont realy no the diff between accuracy and linearity)
Calibration of the thermometer is by putting it in MELTING ice and marking the point of the liquid. Put it in STEAM and mark it. Then divide it to 100 diff marks
2-Thermocouple can be used to measure too... It is small so it can fit into small areas, and cuz its small so its fast. It can read up to 1000*C so its good for industry. Its digital so it can be read on a remote dial...
I can't find a good pic but this is what it consists of : \/ -------------------------- --------------------------------
|
(hot conjunction (the object) V
|
/\ ---------connected to beaker of ice hear) ----------------
Look, the upper wire and the wire under the Voltmeter are made of copper. the one between the ice and hot is made of constantan.
3- Bietallic strip can measure temp too but u just have to know that it is used in stuff like iron (for clothes). What happens is that when u connected to power, two stripes gets heated, as they get more heated on of them expands more and breaks contact, and so 'cut' a circuit and the heating element stops getting current and just stop :P
I will tell you more but just lemme study for some time xD :D
Edit:
Now we will discuss Thermal Capacity:
Thermal Capacity is the amount of heat needed to heat up an object. SPECIFIC heat capacity is: The amount of heat needed to RAISE THE TEMP OF 1 KG OF THE OBJECT BY 1*C.
Experiment for heat capacity:
- For a blockk of metal : A block of metal with a heater in and a thermometer (there is gaps in it to fit them). The heater should be connected to a voltmeter and an ammeter. Put insulation, bla bla... Now record the initial temp and final temp, and record the total time THE HEATER WAS ON. Now just apply the rule c=E/(m*(t2-t1)).
C is the specufic heat capacity, m=mass, t2=final temp, t1=initial. Remember that E(energy) can be calculated like this(very imp): E=VxIxT
So We have Voltage and Current (from voltmeter and ammeter on heater) and we know the total time the heater was on. Multiply them to get E. then just apply the rule...
MELTING AND BOILING:
(http://www.antonine-education.co.uk/New_items/Gateway/p1_energy_for_the_home_files/image001.gif)
So WTF is that... Lemme tell you. As u can see and as u know that when u give smth energy, it becomes hotter, which is exactly what happening in the first line. However the second line shows no change in temp tho we are still giving energy!! WHY? In the first part the energy given was used to make the particles vibrate more... However now that the MELTING POINT is reached, the energy is instead used to loosen the bond between the atoms. Remember, vibrations mean more temp but here its used to loosen the bonds not to add vibrations. Also u have to know that when its used for vibrations it is KINETIC ENERGY, but when its used to loosen the bonds its POTENTIAL ENERGY. Also, the part where the temp is constant shows melting, so there will be BOTH solid and liquid (its still melting). However when it reaches the point where the graph starts to climb again, all the solid is liquid now.
Again the same thing in th beggining happens now, the temp is rising until it reaches boiling point where the energy is instead... bla bla
So, what is this energy called and what is its formula? That my friend willl be in the next episode... (jk xD I will tell u after lunch ;D)
Edit:
The extra energy stored by the water at 0*C, as opposed to ice at 0*C, is the LATENT HEAT OF FUSION
This is they summary of what i explained above!!
The heat required to melt a unit mass of solid, and turned it into liquid is known as the SPECIFIC latent heat of fusion of that solid (symbol L) and is measured in J/Kg or J/g
For gases its called Latent heat of vaporisation
Experiment about Latent Heat:
1-Latent Heat of Fusion of Ice:
a-Weight a beaker without the heater.
b-Dry the ice on a cloth and put into beaker
c-switch heater, start stopwatch
d-stir
e-measure the time taken for the ice to melt
f-weight the beaker plus the water
Very important to know that the FORMULA OF LATENT HEAT IS: L=E/m
this is a bit similar to the previous experiment, all u gotta do is calculate E by VxIxt then divide by m (which is mass of beaker and water - mass of beaker)
2-Latent Heat of Vapourisation of Water:
a- water in beaker
b-weight water+beaker
c-switch on heater
d-WHEN THE WATER BOILS, start the stopwatch and let the water boil for a few minutes
e-weight again
last weight-initial =m and u know the rest......
WATER:
A couple of things u need to know is as i said how it expands below 4C, and that water has a very hight specific heat capacity. This makes it an excelent coolant for machines, bla bla. And this is what makes the temperature of seas and oceans temperature almost steady as they need enormous energy just to increase a couple of degrees.
There is a confusion around the word steam. Steam is colourless and its at 100C. It occurs when u are boiling water in a kettle. THIS IS EXTREMEMLY DANGEROUS. However in a short time it condenses and turn into water droplets which form the whit clouds u see (and u think its steam but its not).
Last thing is bioling is at BIOLING temperature only and molecules from every part of the liquid vapourises (every part means the particles on top and bottom).
Evapouration however happen at any temperature simultaneously and only the particles on the surface vapourise (cuz only these particles have ENOUGH energy to escape)
HOPE THIS HELPS :D ;) :) ;D
Baladya
Post by: Vin on May 22, 2010, 07:52:02 pm
do we have to know the equation to calculate half-life?'
do you know any ?? because i do it by u kno mental calculation .. i never use any formula ..
Post by: $H00t!N& $t@r on May 22, 2010, 07:54:23 pm
'no cz i ws reading some stuff on the internet about half-life and there was this weird formula for calculating half-life so i was jus wondering if we have to know it for igs
do you know any ?? because i do it by u kno mental calculation .. i never use any formula ..
Post by: Vin on May 22, 2010, 07:56:08 pm
i dont understand half of the stuff tht is on wikipedia !! post a ques if u hav i'll tell u how to solve ..
Post by: $H00t!N& $t@r on May 22, 2010, 07:59:48 pm
i dont understand half of the stuff tht is on wikipedia !! post a ques if u hav i'll tell u how to solve ..
i havent started solving pp for physics yet. if i come across a question ill ask
Post by: Adzel on May 22, 2010, 08:35:21 pm
ok u gota kno one thing about half life :: here in this q the half life is 4 days from 100 to 50 right ? so for the count rate to become half (50 to 25)
would be double the time taken ?? forget this .. eg if an isotope of Sodium takes 10 hrs to become half or its half life is 10 hrs .. then a sample of 100
grams would take 10 hrs to become 50g .. further 10 hrs to become 25g further 10 hrs to become 12.5 g .. so apply this logic here ..
dont hesitate to ask if not under stood .. i'll try something else .. ;)
Thanx...thats it, I understand now
Post by: contraentry on May 22, 2010, 08:57:49 pm
Post by: jellybeans on May 23, 2010, 08:39:18 am
i thought it was the forcemeter but the answer said beam balance.. explanation .. anyone? ;) ;) ;)
Post by: jellybeans on May 23, 2010, 08:43:21 am
There are diff ways to measure temp:
1-Liquid in Glass (alchohol or mercury)
Thermometrs are characterised by Sensitivity: which is that when a small amount of heat is given to a liquid, it expands a lot. In this case alchohol expands more. Another way to make it more sensitive is to make the bulb big and the narrow glass tube
HOPE THIS HELPS :D ;) :) ;D
Baladya
ummm question.. if the bulb is bigger, doesnt it contain more liquid & take longer for the liquid to expand? then.. how would it be more sensitive? :-\
Post by: WARRIOR on May 23, 2010, 08:45:02 am
uhmmm for Physic's P1 may/june 2000's Q6 ... Which instrument can be used to give a direct measurement of the mass of a rock on the Moon? choices are : A) bathroom scales, B) Beam Balance, C) Force Meter, D) Top-pan balance ...well you got urslef there !
i thought it was the forcemeter but the answer said beam balance.. explanation .. anyone? ;) ;) ;)
HE SAID MASS . mass is in KG ..But you said forcemeter ! FORCE IS NEWTONS .
bathroom + top man balance will give u mass automatically liek it is on the earth !! i mean look at the formula W= Mx G
when u want to find M = W/G ..and the gravity of moon is diffrent than on earth
but beam balance you keep adding weights and stuff till you get the exact mass !
tricky question tbh !
Post by: jellybeans on May 23, 2010, 08:46:03 am
well you got urslef there !
HE SAID MASS . mass is in KG ..But you said forcemeter ! FORCE IS NEWTONS .
bathroom + top man balance will give u mass automatically liek it is on the earth !! i mean look at the formula W= Mx G
when u want to find M = W/G ..and the gravity of moon is diffrent than on earth
but beam balance you keep adding weights and stuff till you get the exact mass !
tricky question tbh !
lololol okayyyyyy XD guess i shud read questions properly next timeee haha. THANKS ;D
Post by: Vin on May 23, 2010, 08:47:58 am
ummm question.. if the bulb is bigger, doesnt it contain more liquid & take longer for the liquid to expand? then.. how would it be more sensitive? :-\
if the bulb is larger .. larger surface area .. so more sensitive readings
Post by: Helium on May 23, 2010, 08:52:09 am
ok u gota kno one thing about half life :: here in this q the half life is 4 days from 100 to 50 right ? so for the count rate to become half (50 to 25)
would be double the time taken ?? forget this .. eg if an isotope of Sodium takes 10 hrs to become half or its half life is 10 hrs .. then a sample of 100
grams would take 10 hrs to become 50g .. further 10 hrs to become 25g further 10 hrs to become 12.5 g .. so apply this logic here ..
dont hesitate to ask if not under stood .. i'll try something else .. ;)
It never reaches 0 does it.
:o
Post by: WARRIOR on May 23, 2010, 08:53:55 am
ummm question.. if the bulb is bigger, doesnt it contain more liquid & take longer for the liquid to expand? then.. how would it be more sensitive? :-\
http://www.physicsforums.com/showthread.php?t=174853
this will explain evreythng ^
also this 1
If the liquid was only in the capilallary then the volume wouldn't make any difference to the sensitivity. Increase the temperature by 1% would increase volume by 1% and the height in the tube by 1%
But suppose there is a large bulb containing 99% of the mercury and the tube only holds 1%. Now a 1% increase in temperature again gives a 1%increase in volume but this doubles the amount in the tube and so gives a change in the height of 100% not 1%.
Post by: WARRIOR on May 23, 2010, 08:57:45 am
anwyawy basically
! if u havbe 5cm 3 and 100cm3 in diffretn thermometer but both thermometrs have same capillary tube Size
put them both in 100* C
5cm3 will easily expand to teh 100* C but imagin 100cm3 in the same capillary tube tryin to expand !!! it wil expand waaaaaaaay abooooooove caz there si more liquid to expand !!!!!!
what is sesitivity !!!
HOW MUCH THE LIQUID EXPANDS FOR EVERY DEGREE RISE IN TEMP
Post by: J.Darren on May 23, 2010, 09:05:52 am
i wrot ethe asnwer in the qoute ..sorryIf the bulb is bigger, it would affect the resposivness as mercury / alcohol in the bulb takes longer to reach the room temperature.
anwyawy basically
! if u havbe 5cm 3 and 100cm3 in diffretn thermometer but both thermometrs have same capillary tube Size
put them both in 100* C
5cm3 will easily expand to teh 100* C but imagin 100cm3 in the same capillary tube tryin to expand !!! it wil expand waaaaaaaay abooooooove caz there si more liquid to expand !!!!!!
what is sesitivity !!!
HOW MUCH THE LIQUID EXPANDS FOR EVERY DEGREE RISE IN TEMP
The width of the tube affects the sensitivity of the thermometer as different liquids has dirrect expansitivity for the same temperature rise and same volume.
Post by: jellybeans on May 23, 2010, 09:41:08 am
If the bulb is bigger, it would affect the resposivness as mercury / alcohol in the bulb takes longer to reach the room temperature.
The width of the tube affects the sensitivity of the thermometer as different liquids has dirrect expansitivity for the same temperature rise and same volume.
thats what i thought :/
Post by: jellybeans on May 23, 2010, 09:41:48 am
i wrot ethe asnwer in the qoute ..sorry
anwyawy basically
! if u havbe 5cm 3 and 100cm3 in diffretn thermometer but both thermometrs have same capillary tube Size
put them both in 100* C
5cm3 will easily expand to teh 100* C but imagin 100cm3 in the same capillary tube tryin to expand !!! it wil expand waaaaaaaay abooooooove caz there si more liquid to expand !!!!!!
what is sesitivity !!!
HOW MUCH THE LIQUID EXPANDS FOR EVERY DEGREE RISE IN TEMP
thankyou. :)
Post by: Adzel on May 23, 2010, 12:10:41 pm
Post by: Vin on May 23, 2010, 12:18:44 pm
Check attached please...
For this one u hav to do exactly opposite of u did earlier because the question asks 20 hrs BEFORE the sample was tested ..
so u double the weight of the substance
0.48g to 0.96g = 5hrs .. this means it before 5 hrs the sample was 0.95g
0.96g to 1.92g = 5+5 = 10 hrs
1.92 to 3.84g = 10+5 hrs = 15hrs
3.84 to 7.86g = 15 + 5hrs = 20 hrs
Post by: WARRIOR on May 23, 2010, 12:21:14 pm
Check attached please...the question literally says
after 20 hours the mass become .48
and it tells you the half life of this ma is 5 hours
7.68-->3.48-->1.92-->.96--> .48 ( just go backwards ) X 2
5 hours means 4 half lifes to 20 !
better explanation from VIN :p
Post by: WARRIOR on May 23, 2010, 01:06:46 pm
Post by: Ivo on May 23, 2010, 01:12:03 pm
how to asnwer?
Is the answer 33,333J/s (33,300J/s to 3sf).
Using M=DV and P=E/T
Post by: Vin on May 23, 2010, 01:14:57 pm
Is the answer 33333J/s
yea i got the same. . 33,333 J/s
Post by: WARRIOR on May 23, 2010, 01:15:16 pm
Is the answer 33333J/s
yeh its right
explain :)
Post by: Ivo on May 23, 2010, 01:17:44 pm
yeh its right
explain :)
I've modified my post. See earlier for explanation!
Post by: Vin on May 23, 2010, 01:18:49 pm
yeh its right
explain :)
density = mass/volume
vol = 0.005m * 100m2
= 0.5cm3
mass = 1000 *0.5
= 500kg
Q = mL
= 500 * 2 * 10^6
= 1 * 10^9 J
rate / sec = 10^9 / 3 * 10 ^4 ses
= 33,333 J/s
Post by: WARRIOR on May 23, 2010, 01:22:32 pm
thanks :D
Post by: Malak on May 23, 2010, 01:48:34 pm
Q2: Part c - ii (c - i is 1.5 m/s)
Q7: a i knw the answer but dnt knw how to write..
Thx
Post by: WARRIOR on May 23, 2010, 01:55:43 pm
http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_2.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_2.pdf)
Q2: Part c - ii (c - i is 1.
5 m/s)
Q7: a i knw the answer but dnt knw how to write..
Thx
HIGH VOLTAGE = LESS CURRENT
less current = less loss of energy !!!
u could also say with high voltage we dont need to buy thick wires to reduce current
q 2 there isnt C?
Post by: Malak on May 23, 2010, 01:57:21 pm
HIGH VOLTAGE = LESS CURRENT
less current = less loss of energy !!!
u could also say with high voltage we dont need to buy thick wires to reduce current
q 2 there isnt C?
Oopss..! Sorry wrong link for ppr I wanted answers for ppr 3
http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_3.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_3.pdf)
Post by: Ivo on May 23, 2010, 02:01:38 pm
Oopss..! Sorry wrong link for ppr I wanted answers for ppr 3
http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_3.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_3.pdf)
What are you stuck on? I've done this paper before :D
Post by: Vin on May 23, 2010, 02:02:45 pm
Oopss..! Sorry wrong link for ppr I wanted answers for ppr 3
http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_3.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2002%20Jun/0625_s02_qp_3.pdf)
Q2) c) velocity is a vector quantity .. so add 9.5 m/s to 8 m/s = 17.5 m/s
7a) ok so when one sphere is rubbed, it transfers electrons to other sphere and becomes positive and the other sphere become negative
Post by: WARRIOR on May 23, 2010, 02:05:05 pm
AT POINT B AND POINT D :/ and subtract
it says whilst the ball is in contact..or maybe u dont uderstand teh graph !
DUE TO RUBBING , 1 SPHERE LOSES ELCTRONS SO THIS SPHERE BECOMES POSOTIVE..THE OTHER SPERHE ACCEPTS THIS ELECTRON AND BECOMES NEGATIVE
Post by: Ivo on May 23, 2010, 02:06:08 pm
7a) ok so when one sphere is rubbed, it transfers electrons to other sphere and becomes positive and the other sphere become negative
Electrons are rubbed off one sphere, which become positive (loses electrons). These electrons are then deposited on other sphere, becomes negative (gains electrons).
Post by: WARRIOR on May 23, 2010, 02:11:39 pm
E/T = P/S.L.H
IS E/T RIGHT??I WANA MAKE SURE?
Post by: Ivo on May 23, 2010, 02:12:19 pm
is it
E/T = P/S.L.H
IS E/T RIGHT??I WANA MAKE SURE?
Power = Energy/Time
Post by: $H00t!N& $t@r on May 23, 2010, 02:40:11 pm
for example in m/j 2002 q8e(ii) why do u use E=IVT and nt E=pxt??
Post by: Ivo on May 23, 2010, 02:42:20 pm
when do u use E=IVT and E=PxT
for example in m/j 2002 q8e(ii) why do u use E=IVT and nt E=pxt??
You apply the formulas to each question, and see what they provide and what you need to find out.
In that question, you are given the voltage (12V), the current (2A) and time (30), and you want to find Energy so you apply E=VIT.
Answer, By the way, is 0.72kWh
Post by: WARRIOR on May 23, 2010, 02:42:52 pm
when do u use E=IVT and E=PxT
for example in m/j 2002 q8e(ii) why do u use E=IVT and nt E=pxt??
ITS TEH SAME THING !!
V X I = P ...
SO ITS P XT . insted of V X I X T
Post by: $H00t!N& $t@r on May 23, 2010, 02:46:56 pm
ITS TEH SAME THING !!
V X I = P ...
SO ITS P XT . insted of V X I X T
u sure ur ans is right?
Post by: holtadit on May 23, 2010, 02:48:14 pm
u sure ur ans is right?
Hes correct. :)
Post by: Malak on May 23, 2010, 03:19:45 pm
And how can we use a meter rule and a pivot to calculate mass (100 g)?
thx
Post by: WARRIOR on May 23, 2010, 03:40:30 pm
well
put the ruler on a pivot. and make sure ruler is devided eaclty on half
put the rock on the ruler..close to the pivot !
and then add a knows mass at diffrnt distances until the ruller balances.
MEASURE THE DISTANCE AND TIMES IT BY THE THE KNOWN MASS
and then divide it by the distance of of rock from pivot and you get the mass
Post by: 2010 on May 23, 2010, 04:01:00 pm
i know the inputs and outputs for both gates but still don't understand how they will be placed...
Its on page 13.....
http://www.freeexampapers.us/IGCSE/Physics/CIE/2007%20Nov/0625_w07_qp_3.pdf
Post by: Malak on May 23, 2010, 04:07:31 pm
yuo place 1 junction ( cold ) n pure metling ice at 0 * C . place the hot one in the hot object. Difrence in temperature creates a current and this current is measure by a galvanometer calibrated in * C
well
put the ruler on a pivot. and make sure ruler is devided eaclty on half
put the rock on the ruler..close to the pivot !
and then add a knows mass at diffrnt distances until the ruller balances.
MEASURE THE DISTANCE AND TIMES IT BY THE THE KNOWN MASS
and then divide it by the distance of of rock from pivot and you get the mass
Umm..Kinda confused here...Measure which distance? and thn divide by which distance?
Can u draw this situation?
thx
Post by: Ghost Of Highbury on May 23, 2010, 04:13:19 pm
i need help with o/n 07 Quest.10(b)
i know the inputs and outputs for both gates but still don't understand how they will be placed...
Its on page 13.....
http://www.freeexampapers.us/IGCSE/Physics/CIE/2007%20Nov/0625_w07_qp_3.pdf
attached
Post by: WARRIOR on May 23, 2010, 04:19:23 pm
Umm..Kinda confused here...Measure which distance? and thn divide by which distance?
Can u draw this situation?
thx
Post by: WARRIOR on May 23, 2010, 04:20:32 pm
attached
PAINT FTW!
Post by: The Golden Girl =D on May 23, 2010, 04:43:54 pm
PAINT FTW!
By the way what does FTW stand for ?
Post by: Syed Kazim on May 23, 2010, 04:47:30 pm
By the way what does FTW stand for ?
For The Win.
Post by: The Golden Girl =D on May 23, 2010, 04:48:45 pm
For The Win.
aha :-[
Post by: Malak on May 23, 2010, 10:35:10 pm
Q8 Part b
Q11 all parts
Thx
Post by: astarmathsandphysics on May 23, 2010, 10:39:03 pm
Q11 all parts
Thx
q8 when a coil turns inside a magnetic field a current is produced JUST LIKE THAT
Post by: Malak on May 24, 2010, 02:39:03 pm
Thx
Post by: holtadit on May 24, 2010, 02:41:49 pm
Wats the answer...and why?
Thx
A
Small temp rise = large thermal capacity
large temp rise = small thermal capcity.
Post by: WARRIOR on May 24, 2010, 02:50:24 pm
subtances which take alot of time to heat HAVE HIGHT THERMAL CAPACITY ( water )
"""""""""""""""""""""""""""""""less time to heat HAVE LOW THERMAL CAPACITY ( METALS ) --THERMOCOUPLE.. thats why it can measure fast changing temp ..take very little time to heat up
Post by: Mr.DitD on May 24, 2010, 03:17:21 pm
If there is only one things i do not understand in the whole school syllabus it's the TRANSISTOR. So can someone please explain the transister in detail and say how it works exactly. If you use a diagram or example it would really help.
In the book I have it only says: If there is a current in the base and collecter then there is a current in emitter. HOWEVER, my teacher says it has nothing to do with current, and if the potential difference between the base and emitter is more than 0.7 then there is a current in collecter. ??? ??? ???
Please help!!!!!!!
Post by: Ghost Of Highbury on May 24, 2010, 03:29:30 pm
Hello everyone!!
If there is only one things i do not understand in the whole school syllabus it's the TRANSISTOR. So can someone please explain the transister in detail and say how it works exactly. If you use a diagram or example it would really help.
In the book I have it only says: If there is a current in the base and collecter then there is a current in emitter. HOWEVER, my teacher says it has nothing to do with current, and if the potential difference between the base and emitter is more than 0.7 then there is a current in collecter. ??? ??? ???
Please help!!!!!!!
Its best if u understand the transistor circuits with thermistors and varying resistance...wait for 5 minutes..ill draw the diagrams and write the explanation.
Post by: Ghost Of Highbury on May 24, 2010, 03:43:20 pm
Its best if u understand the transistor circuits with thermistors and varying resistance...wait for 5 minutes..ill draw the diagrams and write the explanation.
Ok attached.
EDIT : "0.6V" not "06V"
Post by: WARRIOR on May 24, 2010, 03:47:09 pm
Ok attached.
umm i think its wrong
THE VOLATAGE ACCROSS THE VARIABLE RESISTOR SHOULD BE HIGH SO THE VOLTAGE ACCORSE B-E HIGH TOO RIGHT?
Post by: Ghost Of Highbury on May 24, 2010, 03:52:02 pm
Post by: Mr.DitD on May 24, 2010, 03:58:26 pm
Ok attached.
EDIT : "0.6V" not "06V"
Thanks. But im still confused. The resistance of thermistor decreases when there is heat*.
I didnt understand what u mean by share of Voltage, does it mean the voltage across it.
So in this case when there is low temp, resistance of thermistor increases. As a result, will there be higher OR lower voltage across thermistor?!?!
And if the voltage across thermistor increases, will there be a lower voltage in the variable resistor, which means Vbe will be high??!?!
Post by: WARRIOR on May 24, 2010, 03:59:06 pm
Thats exactly wat i said. My IGCSE book says the same thing, im pretty sure this isnt wrong.
when resistance of teh thermistor decreases..doesnt it get less voltage???
and therefore the variable resistor gets more voltage
and therefore the voltage accors teh base emiitor is high?
Post by: WARRIOR on May 24, 2010, 04:00:19 pm
Thanks. But im still confused. The resistance of thermistor decreases when there is heat*.
I didnt understand what u mean by share of Voltage, does it mean the voltage across it.
So in this case when there is low temp, resistance of thermistor increases. As a result, will there be higher OR lower voltage across thermistor?!?!
And if the voltage across thermistor increases, will there be a lower voltage in the variable resistor, which means Vbe will be high??!?!
thats exactly what im asking !! By the way HIGH TEMP DECREASES THE RESISTANCE OF THERMISTOR
Post by: holtadit on May 24, 2010, 04:00:32 pm
Hence, the thermistor should have a lower resistance (example when heated) than the VARIABLE resistor in order for the V output to the transistor to EXCEED 0.6 V and hence trigger the transistor.
Post by: Ghost Of Highbury on May 24, 2010, 04:02:59 pm
when resistance of teh thermistor decreases..doesnt it get less voltage???
and therefore the variable resistor gets more voltage
and therefore the voltage accors teh base emiitor is high?
High temperature - Less resistance k? V = I*R. when R decreases, V decreases. Thus, it gets less voltage and the Variable resistor side gets more voltage.
Post by: holtadit on May 24, 2010, 04:03:56 pm
What I said does it make sense ??
Post by: Ghost Of Highbury on May 24, 2010, 04:05:43 pm
R1 should be LESS than R2 for the Voltage output to BE HIGH.
Hence, the thermistor should have a lower resistance (example when heated) than the VARIABLE resistor in order for the V output to the transistor to EXCEED 0.6 V and hence trigger the transistor.
Yes, thats exactly wat i said. Whats the confusion about?
applying V-I*R, when R decreases (thermistor), the Voltage decreases. So, the other part, Vbe , the variable resistor part gets more voltage, and if V>0.6V is flowing throught the emitter of the transistor, the transistor switches on.
Post by: Mr.DitD on May 24, 2010, 04:06:07 pm
R1 should be LESS than R2 for the Voltage output to BE HIGH.
Hence, the thermistor should have a lower resistance (example when heated) than the VARIABLE resistor in order for the V output to the transistor to EXCEED 0.6 V and hence trigger the transistor.
I think u're right. But what is exactly "voltage output"!?!?
I have a very big issue with voltage!!! ???
By the way can someone please explain the general functioning of the transistors!?!?!
Post by: Ghost Of Highbury on May 24, 2010, 04:07:05 pm
I think u're right. But what is exactly "voltage output"!?!?
I have a very big issue with voltage!!! ???
By the way can someone please explain the general functioning of the transistors!?!?!
The voltage in the emitter part of the transistor?
Post by: holtadit on May 24, 2010, 04:07:56 pm
I think u're right. But what is exactly "voltage output"!?!?
I have a very big issue with voltage!!! ???
By the way can someone please explain the general functioning of the transistors!?!?!
Dude, such questions are for three marks.
The MS gives three points - just memorise them; few days left to the exam and you have no other choice.
Post by: Malak on May 24, 2010, 04:08:15 pm
Q15 Why is it D?
Q18 ans and Explaination
Q31 ans and Explaination
Thx :)
Post by: WARRIOR on May 24, 2010, 04:08:53 pm
Yes, thats exactly wat i said. Whats the confusion about?
applying V-I*R, when R decreases (thermistor), the Voltage decreases. So, the other part, Vbe , the variable resistor part gets more voltage, and if V>0.6V is flowing throught the emitter of the transistor, the transistor switches on.
i got it !! jut one last thing i want to clear.
if teh voltage accroos the variable resistor is HIGHT does that mean voltage across Vbe will be high?
Post by: Ghost Of Highbury on May 24, 2010, 04:11:31 pm
i got it !! jut one last thing i want to clear.
if teh voltage accroos the variable resistor is HIGHT does that mean voltage across Vbe will be high?
yes, actually, the voltage across Vb/e is high, as the variable resistor is a part of that side, v also say the voltage across Variable resistor is high.
Post by: WARRIOR on May 24, 2010, 04:16:23 pm
http://www.freeexampapers.us/IGCSE/Physics/CIE/2006%20Nov/0625_w06_qp_1.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2006%20Nov/0625_w06_qp_1.pdf)
Q15 Why is it D?
Q18 ans and Explaination
Q31 ans and Explaination
Thx :)
THE HEAT GIVEN AT MELTING POINTS AND BOIILING POINTS IS CALLED LATENT HEAT / ENERGY
the heat is used to BREAK BONDS between molecules in order t chnage state .It is not used to give kinteic energy to molecules therfore doesnt heat the molecules up and no temp rise
18- C??? best for convectional currents if u dotn kno ask
IS D THE ASNWER OF 31
Post by: WARRIOR on May 24, 2010, 04:19:11 pm
yes, actually, the voltage across Vb/e is high, as the variable resistor is a part of that side, v also say the voltage across Variable resistor is high.oki doki ..thanks man AGAIN
i thought i got this before but hmm :/
should be fine now ;)
Post by: Ghost Of Highbury on May 24, 2010, 04:24:11 pm
oki doki ..thanks man AGAIN
i thought i got this before but hmm :/
should be fine now ;)
no problem
Post by: Malak on May 24, 2010, 04:24:37 pm
THE HEAT GIVEN AT MELTING POINTS AND BOIILING POINTS IS CALLED LATENT HEAT / ENERGY
the heat is used to BREAK BONDS between molecules in order t chnage state .It is not used to give kinteic energy to molecules therfore doesnt heat the molecules up and no temp rise
18- C??? best for convectional currents if u dotn kno ask
IS D THE ASNWER OF 31
Okey i get the first one
And 18 is C but why ???
and 31 also can u explain a bit? y D
Post by: Ghost Of Highbury on May 24, 2010, 04:40:44 pm
Okey i get the first one
And 18 is C but why ???
and 31 also can u explain a bit? y D
for the circuit to be complete, the current shud move from positive, through all the lamps, lastly through D, and to the negative.
If D breaks, the circuit isnt complete.
Post by: Ghost Of Highbury on May 24, 2010, 04:42:37 pm
Okey i get the first one
And 18 is C but why ???
and 31 also can u explain a bit? y D
ok u know it has to be smewhere low for the warm air to rise and spread all over. the only two low points are D and C. answer is C because from C, there is a path for the warm air to rise...it can also spread horizontally and spread.
Post by: Malak on May 24, 2010, 04:48:03 pm
Thx
Post by: Ghost Of Highbury on May 24, 2010, 05:01:58 pm
Post by: Malak on May 24, 2010, 05:43:02 pm
(First Variant)
Q11: The answer is B but i dnt get one thing..Isnt the level of mercury supposed to be lower since the diameter of tube increased?
Q34
thx
Post by: holtadit on May 24, 2010, 05:48:35 pm
Post by: WARRIOR on May 24, 2010, 05:55:14 pm
http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Jun/0625_s09_qp_1.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Jun/0625_s09_qp_1.pdf)yes in a liquid !!
(First Variant)
Q11: The answer is B but i dnt get one thing..Isnt the level of mercury supposed to be lower since the diameter of tube increased?
Q34
thx
ari do u have figures or formulas by which u can prove that ??
for q 34
its C
the curl ur fingers rule
ince current is goin upper do a thumbs up!! lookk how ur fingers curl..they curl anti clock wise ..draw circle around the wire and ull find the answer
1x10^ 5= M X G X H
Post by: Malak on May 24, 2010, 06:12:23 pm
yes in a liquid !!
ari do u have figures or formulas by which u can prove that ??
for q 34
its C
the curl ur fingers rule
ince current is goin upper do a thumbs up!! lookk how ur fingers curl..they curl anti clock wise ..draw circle around the wire and ull find the answer
1x10^ 5= M X G X H
I still dont get Q34 sorry ???
Post by: WARRIOR on May 24, 2010, 06:14:21 pm
I still dont get Q34 sorry ???
http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/imgmag/magcur.gif
Post by: Ghost Of Highbury on May 24, 2010, 06:54:11 pm
http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/imgmag/magcur.gif
[/quote
ok try this, make ur fingers as shown in the diagram...the way the fingers are wrapped around show how the magnetic lines will be...
check the diagram..check the red arrows which indicate the magnetic field an and direction..
only the red arrow near C matches the compass arrow..
Post by: WARRIOR on May 24, 2010, 07:07:09 pm
http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/imgmag/magcur.gif
[/quote
ok try this, make ur fingers as shown in the diagram...the way the fingers are wrapped around show how the magnetic lines will be...
check the diagram..check the red arrows which indicate the magnetic field an and direction..
only the red arrow near C matches the compass arrow..
aadi can u explain to me why the barometers diamter doest affect height? i kno by heart that it doesnt..but for what reason exactly..( dont say the area doesnt affcet height :P or say with with a good reason :P)
Post by: Malak on May 24, 2010, 07:10:02 pm
http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/imgmag/magcur.gif
ok try this, make ur fingers as shown in the diagram...the way the fingers are wrapped around show how the magnetic lines will be...
check the diagram..check the red arrows which indicate the magnetic field an and direction..
only the red arrow near C matches the compass arrow..
Get it now..Thx :D
Post by: Ghost Of Highbury on May 24, 2010, 07:16:59 pm
aadi can u explain to me why the barometers diamter doest affect height? i kno by heart that it doesnt..but for what reason exactly..( dont say the area doesnt affcet height :P or say with with a good reason :P)
ok here
The weight mercury in the barometer = AHdg,
where 'A' = area of cross-section
H' is the height of the mercury column
d is the density
g is the acceleration due to gravity = 9.8 m/s^2
But the pressure p is the weight per unit area.
So if you divide AHdg by 'A' you get p=Hdg i.e p = height*density*acc. due to gravity
You can now notice that the pressure is independent of the value of the cross-sectional area ((diamter/2)^2 * pi)
Post by: WARRIOR on May 24, 2010, 07:21:04 pm
ok herei seeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee !
The weight mercury in the barometer = AHdg,
where 'A' = area of cross-section
H' is the height of the mercury column
d is the density
g is the acceleration due to gravity = 9.8 m/s^2
But the pressure p is the weight per unit area.
So if you divide AHdg by 'A' you get p=Hdg i.e p = height*density*acc. due to gravity
You can now notice that the pressure is independent of the value of the cross-sectional area ((diamter/2)^2 * pi)
thanks man uv been really helpful !
Post by: Ghost Of Highbury on May 24, 2010, 07:21:56 pm
Post by: Malak on May 24, 2010, 07:33:37 pm
Post by: Ghost Of Highbury on May 24, 2010, 07:35:16 pm
Post by: WARRIOR on May 24, 2010, 07:35:47 pm
NO AIR IN THE MOOOOOOOOOON ( NO MOLECULES )
NO VIBRATION
Post by: Malak on May 24, 2010, 07:44:10 pm
Thx both :)
Post by: Malak on May 24, 2010, 10:15:35 pm
http://www.freeexampapers.us/IGCSE/Physics/CIE/2007%20Nov/0625_w07_qp_1.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2007%20Nov/0625_w07_qp_1.pdf)
Thx
Post by: Vin on May 24, 2010, 10:21:51 pm
Q13 & 21
http://www.freeexampapers.us/IGCSE/Physics/CIE/2007%20Nov/0625_w07_qp_1.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2007%20Nov/0625_w07_qp_1.pdf)
Thx
ok Q
13) D, always wen the pressure increases mercury level rises .. and the space P is always a vacuum .. so it is not affected by pressure ;)
21)B, the ques says "still water" so water in the space AB will take the space BC wen there are no waves hence the surface is B
Post by: The Golden Girl =D on May 24, 2010, 10:23:55 pm
ok Q
13) D, always wen the pressure increases mercury level rises .. and the space P is always a vacuum .. so it is not affected by pressure ;)
21)B, the ques says "still water" so water in the space AB will take the space BC wen there are no waves hence the surface is B
Vin i am so sleepy so i'm going to log off.......FYI u've got chem pp1 tomorrow , so go sleep young man !!
Post by: Baladya on May 24, 2010, 11:09:27 pm
https://studentforums.biz/index.php/topic,8099.0.html (https://studentforums.biz/index.php/topic,8099.0.html)
U can ask me warever u want :)
Post by: Vin on May 24, 2010, 11:11:49 pm
Vin i am so sleepy so i'm going to log off.......FYI u've got chem pp1 tomorrow , so go sleep young man !!
yea i know.. im sleepy too .. best of luck ... if u happen to read this .. :D
Post by: Adzel on May 25, 2010, 10:26:26 am
Post by: jellybeans on May 25, 2010, 10:28:30 am
See attached...+ explaination of answer.
answer's B cuz it takes 2 days to reach HALF of 200, which is 100. and monday-weds is two days :)
Post by: Adzel on May 25, 2010, 10:39:39 am
answer's B cuz it takes 2 days to reach HALF of 200, which is 100. and monday-weds is two days :)
Ohh...didn't relize that....thanks!
Post by: jellybeans on May 25, 2010, 10:55:25 am
Ohh...didn't relize that....thanks!
no probs :)
Post by: 8T on May 25, 2010, 11:20:27 am
Can some1 plz give me the answer of october 02 p1 q 37 & explain if possible?
Post by: Moonlyte on May 25, 2010, 11:36:01 am
Hello.
Can some1 plz give me the answer of october 02 p1 q 37 & explain if possible?
The ans is C - it increases a little.
Post by: Moonlyte on May 25, 2010, 11:37:47 am
Here's the link for the paper:
http://www.freeexampapers.com/FreeExamPapers.com_.php?__lo=SUdDU0UvUGh5c2ljcy9DSUUvMjAwOSBOb3YvMDYyNV93MDlfcXBfMS5wZGY=
Post by: Ghost Of Highbury on May 25, 2010, 11:44:58 am
Could someone please help me with Nov 2009 number 17? The answer is A, but i dont know why.
Here's the link for the paper:
http://www.freeexampapers.com/FreeExamPapers.com_.php?__lo=SUdDU0UvUGh5c2ljcy9DSUUvMjAwOSBOb3YvMDYyNV93MDlfcXBfMS5wZGY=
if u cool the water at X, the cool water will move down, hence pushing the warmer water below upwards. a convection current is set up
Post by: Adzel on May 25, 2010, 11:45:55 am
Could someone please help me with Nov 2009 number 17? The answer is A, but i dont know why.
Here's the link for the paper:
http://www.freeexampapers.com/FreeExamPapers.com_.php?__lo=SUdDU0UvUGh5c2ljcy9DSUUvMjAwOSBOb3YvMDYyNV93MDlfcXBfMS5wZGY=
(http://www.freeimagehosting.net/uploads/d09f2e2097.png)
Post by: 8T on May 25, 2010, 11:48:17 am
And abt ur question what if we stir at Y what will happen then cz thts what i picked in o/n 09 q 17
Post by: Adzel on May 25, 2010, 12:04:55 pm
Post by: 8T on May 25, 2010, 12:08:32 pm
Post by: Adzel on May 25, 2010, 12:10:39 pm
Post by: 8T on May 25, 2010, 12:13:16 pm
THen full 2 * 0.4 = 0.8
So 1.3- 0.8 = 0.5 which is B
Hope u got it :)
Post by: Vin on May 25, 2010, 12:15:15 pm
Yes...
ok so the second one shows the bottle wen half used .. so this is mass of oil + the bottle so if u double it to 1.8 Kg .. this will be mass of original (wen full) + bottle .. so to find the weight of the bottle
1.8 - 1.3 = 0.5Kg
Post by: Vin on May 25, 2010, 12:16:38 pm
Isnt the half (1.3 - 0.9 = 0.4)
THen full 2 * 0.4 = 0.8
So 1.3- 0.8 = 0.5 which is B
Hope u got it :)
lol .. two diff. methods :P Adzel i think u should stick by this one ;)
Post by: 8T on May 25, 2010, 12:18:45 pm
He could do his job choosing Lol
I like urs 2 .. i like dif ways :)
Post by: Vin on May 25, 2010, 12:22:10 pm
haha .. let him choose .. now ppl. are getting choices too :P XD
Adzel By the way which paper is it ?? i never solved this one .. i better do ;)
Post by: ambitious94 on May 25, 2010, 12:25:51 pm
Could someone please help me with Nov 2009 number 17? The answer is A, but i dont know why.Happened to have just done that paper ;D
Here's the link for the paper:
http://www.freeexampapers.com/FreeExamPapers.com_.php?__lo=SUdDU0UvUGh5c2ljcy9DSUUvMjAwOSBOb3YvMDYyNV93MDlfcXBfMS5wZGY=
Okay, so let's eliminate the incorrect choices. C and D are IMPOSSIBLE. Why, since we want a CONVECTION current to be set up. so there has a to be a difference in temperatures of the particles, not simply moving them.
So now if we cool it at Y- since it is already at the bottom of the beaker, won't move upwards, so no current, it just stays where it is.
SO now the only plausible solution we have is A, so if we cool the water at X, it'll move downwards due to being denser n here you go- ur very own CONVECTION CURRENT ;D
Hope I made sense to u
Post by: ambitious94 on May 25, 2010, 12:27:53 pm
First Question:
A ball is thrown upwards.
What effect does the force of gravity have on the ball?
A It produces a constant acceleration downwards.
B It produces a constant acceleration upwards.
C It produces a decreasing acceleration upwards.
D It produces an increasing acceleration downwards.
Answer's A. How can it accelerate downwards, when it's mocing upwards? ???
Post by: kashim on May 25, 2010, 12:30:04 pm
Post by: Vin on May 25, 2010, 12:31:16 pm
Now my turn to get help :P
First Question:
A ball is thrown upwards.
What effect does the force of gravity have on the ball?
A It produces a constant acceleration downwards.
B It produces a constant acceleration upwards.
C It produces a decreasing acceleration upwards.
D It produces an increasing acceleration downwards.
Answer's A. How can it accelerate downwards, when it's mocing upwards? ???
read the ques ! What effect does the force of gravity have on the ball? acts always downwards ;) uniformly on a body ..
Post by: ambitious94 on May 25, 2010, 12:31:56 pm
The object in the diagram is acted upon by the two forces shown.
3N--> object<--2N
What is the effect of these forces?
A The object moves to the left with constant speed.
B The object moves to the left with constant acceleration.
C The object moves to the right with constant speed.
D The object moves to the right with constant acceleration.
Answer's D. Just wanna clarify. A resultant force on an object causes it to accelerate then move in a constant speed, or does it cause it to accelerate constantly? :S HELP HELLPPPP
Post by: Vin on May 25, 2010, 12:33:06 pm
Can somebody upload the physics AQA A unit 2 January 2010 paper and mark scheme? I'm really struggling in general and really need as much practice as possible.
HAVE U POSTED IN THE RIGHT BOARD ??
Post by: ambitious94 on May 25, 2010, 12:33:40 pm
read the ques ! What effect does the force of gravity have on the ball? acts always downwards ;) uniformly on a body ..OOOH YEA...well ain't u genius ;) :D....THANKSSSSSSSSSS
Post by: Ghost Of Highbury on May 25, 2010, 12:35:47 pm
Next question:
The object in the diagram is acted upon by the two forces shown.
3N--> object<--2N
What is the effect of these forces?
A The object moves to the left with constant speed.
B The object moves to the left with constant acceleration.
C The object moves to the right with constant speed.
D The object moves to the right with constant acceleration.
Answer's D. Just wanna clarify. A resultant force on an object causes it to accelerate then move in a constant speed, or does it cause it to accelerate constantly? :S HELP HELLPPPP
Accelerate constantly.
F = ma
1N = ma
1N/m = a
m is constant, thus a is constant.
Post by: Vin on May 25, 2010, 12:36:36 pm
Next question:
The object in the diagram is acted upon by the two forces shown.
3N--> object<--2N
What is the effect of these forces?
A The object moves to the left with constant speed.
B The object moves to the left with constant acceleration.
C The object moves to the right with constant speed.
D The object moves to the right with constant acceleration.
Answer's D. Just wanna clarify. A resultant force on an object causes it to accelerate then move in a constant speed, or does it cause it to accelerate constantly? :S HELP HELLPPPP
ok .. in this case .. it cannot be CONSTANT SPEED because the force acting on a body will INCREASE the speed UNIFORMLY as the force is being applied the bidy moves with a constant acceleration
Post by: Vin on May 25, 2010, 12:37:37 pm
Can somebody upload the physics AQA A unit 2 January 2010 paper and mark scheme? I'm really struggling in general and really need as much practice as possible.
@ Aadi .. what board is kashim talking abt ?? jan 2010 ?!?
Post by: Adzel on May 25, 2010, 12:40:19 pm
By the way its M/J 07
Post by: Ghost Of Highbury on May 25, 2010, 12:40:54 pm
@ Aadi .. what board is kashim talking abt ?? jan 2010 ?!?
No clue
Post by: jellybeans on May 25, 2010, 12:41:34 pm
dont get it :( is it cuz its.. totally internally reflecteeeed? :/
Post by: Ghost Of Highbury on May 25, 2010, 12:43:19 pm
..help ? :)
dont get it :( is it cuz its.. totally internally reflecteeeed? :/
B?
Post by: Moonlyte on May 25, 2010, 12:44:40 pm
Happened to have just done that paper ;D
Okay, so let's eliminate the incorrect choices. C and D are IMPOSSIBLE. Why, since we want a CONVECTION current to be set up. so there has a to be a difference in temperatures of the particles, not simply moving them.
So now if we cool it at Y- since it is already at the bottom of the beaker, won't move upwards, so no current, it just stays where it is.
SO now the only plausible solution we have is A, so if we cool the water at X, it'll move downwards due to being denser n here you go- ur very own CONVECTION CURRENT ;D
Hope I made sense to u
thanks to you and everyone else who answered it! :)
Post by: holtadit on May 25, 2010, 12:45:27 pm
..help ? :)
dont get it :( is it cuz its.. totally internally reflecteeeed? :/
Its B.
The ray travels along the normal and doesnt refract.
Then it hits the slanted edge of the prism and undergoes total internal reflection.
So its REFLECTED at an angle of 45 degrees downwards where it hits the prism side along the normal and without refracting.
Post by: Vin on May 25, 2010, 12:46:47 pm
B?
yup ..
logic ?? only this one makes sense !! u gotta remember hoe reflection occurs in a a reflecting prism
Post by: ambitious94 on May 25, 2010, 12:51:25 pm
Accelerate constantly.Ohhh. Thanks 2 u n VIN as well! XD
F = ma
1N = ma
1N/m = a
m is constant, thus a is constant.
Post by: Moonlyte on May 25, 2010, 12:53:34 pm
Post by: holtadit on May 25, 2010, 12:58:07 pm
is the marking scheme ever wrong?
The MS for those really old papers can be wrong - they were made by some teacher.
For the NEW papers from like 2001 onwards - the MS is ALWAYS CORRECT.
Post by: Nobody on May 25, 2010, 12:58:50 pm
Can somebody upload the physics AQA A unit 2 January 2010 paper and mark scheme? I'm really struggling in general and really need as much practice as possible.
Sorry, but i could't find it anywhere..
But the latest is here..
http://web.aqa.org.uk/qual/newgcses/science/new/physics_materials.php
Post by: Navthep on May 25, 2010, 01:04:16 pm
There is one question, June 2006 : P1 : Q16 , the answer is A but i think its B.
Can anyone explain it to me? I have to do the real IG exam tomorrow! (P1)
Thanksss
Post by: holtadit on May 25, 2010, 01:05:51 pm
Hey guys, i really need help about thermal capacity of an object.
There is one question, June 2006 : P1 : Q16 , the answer is A but i think its B.
Can anyone explain it to me? I have to do the real IG exam tomorrow! (P1)
Thanksss
HIGH thermal capcaity = SMALL temp rise.
LOW thermal capacity = LARGE temp rise.
Answer = B
Post by: Moonlyte on May 25, 2010, 01:06:44 pm
The MS for those really old papers can be wrong - they were made by some teacher.
For the NEW papers from like 2001 onwards - the MS is ALWAYS CORRECT.
thanks!
Post by: Malak on May 25, 2010, 01:07:09 pm
Thx
Post by: Malak on May 25, 2010, 01:08:14 pm
HIGH thermal capcaity = SMALL temp rise.
LOW thermal capacity = LARGE temp rise.
Answer = B
Can u explain..Wat the high/low thermal capactiy actually means..?
Thx
Post by: Navthep on May 25, 2010, 01:08:50 pm
HIGH thermal capcaity = SMALL temp rise.
LOW thermal capacity = LARGE temp rise.
Answer = B
Thanks a lot man, so can I just simply see the smallest temp rise to answer this type of question? :P
Post by: Moonlyte on May 25, 2010, 01:08:54 pm
Hey guys, i really need help about thermal capacity of an object.
There is one question, June 2006 : P1 : Q16 , the answer is A but i think its B.
Can anyone explain it to me? I have to do the real IG exam tomorrow! (P1)
Thanksss
thermal capacity means that it takes a lot of energy to increase the temperature by 1 degrees, no matter what the size is. in Q16, all 4 blocks were given the SAME energy, but A increased LEAST, so A is the answer.
Post by: holtadit on May 25, 2010, 01:10:53 pm
Can u explain..Wat the high/low thermal capactiy actually means..?
Thx
Water has a high thermal capcity. That means it takes A VERY LARGE AMOUNT of heat to raise its temp by 1 degree centigrade.
LOW thermal capacity means only a small amount of heat is needed to cause a LARGE temp rise.
Got it ? Ask again if you haven't.
Post by: Navthep on May 25, 2010, 01:13:58 pm
Thankss :D
pS - Thanks to all who explained me thermal capacity. Really mean it. :)
Post by: holtadit on May 25, 2010, 01:14:23 pm
The answer is A but Why...Arent the electrons in outer orbits? ???
Thx
An unstable atomic nucleus with an excess of neutrons may undergo ?? decay, where a neutron is converted into a proton
and an electron
So technically the neutron which is in the nucleus is the source of Beta Radiation ;)
Post by: Malak on May 25, 2010, 01:15:49 pm
Water has a high thermal capcity. That means it takes A VERY LARGE AMOUNT of heat to raise its temp by 1 degree centigrade.Yeah got it...But one thing...The one with high themal capacity is also the one that cools down quickly right?
LOW thermal capacity means only a small amount of heat is needed to cause a LARGE temp rise.
Got it ? Ask again if you haven't.
thx
Post by: holtadit on May 25, 2010, 01:18:45 pm
Yeah got it...But one thing...The one with high themal capacity is also the one that cools down quickly right?
thx
no.
Check my post on the Beta radiation. ABOVE.
Post by: Malak on May 25, 2010, 01:21:33 pm
no.Yeah i checked that thx :D
Check my post on the Beta radiation. ABOVE.
Ohkay and can u explain..How water act a coolant?
Thx alot
Post by: holtadit on May 25, 2010, 01:24:21 pm
Yeah i checked that thx :D
Ohkay and can u explain..How water act a coolant?
Thx alot
Water has a HIGH thermal capacity.
So it can absorb a LARGE amount of heat with only a SMALL temp rise.
In adittion it only expands SLIGHTLY. So its a good coolant.
Post by: Malak on May 25, 2010, 01:25:20 pm
Water has a HIGH thermal capacity.
So it can absorb a LARGE amount of heat with only a SMALL temp rise.
In adittion it only expands SLIGHTLY. So its a good coolant.
Ohkeyy....! Get it
thx
Post by: 8T on May 25, 2010, 01:29:03 pm
Post by: jellybeans on May 25, 2010, 01:29:29 pm
Um, can anyone explain convection currents? I'm somewhat confused :S
Thankss :D
pS - Thanks to all who explained me thermal capacity. Really mean it. :)
hot air rises and cold air falls. this is cuz when something is hot, it has more energy to move around hence it moves further apart and become less dense.. so it rises ... and cold air is closer together hence denser.. so it falls... :)
Post by: Moonlyte on May 25, 2010, 01:30:36 pm
#30:C
#31:A
#34:C
#37:A
Those are the answers but I dont know why. Please help!
Link for the paper:
http://www.freeexampapers.com/FreeExamPapers.com_.php?__lo=SUdDU0UvUGh5c2ljcy9DSUUvMjAwOSBKdW4vMDYyNV9zMDlfcXBfMS5wZGY=
Post by: Snake on May 25, 2010, 01:34:13 pm
Post by: 8T on May 25, 2010, 01:36:55 pm
I will check the rest and come back to yew dear :)
Post by: holtadit on May 25, 2010, 01:38:13 pm
Anyone cares to explain to me q 14 o/n 04 p1 ofc .. why is it B i thought it would be A more force per unit are ??
Only a temperature INCREASE would give the molecules more KINETIC ENRGY and cause GREATER/HARDER collisions.
BUT the question says the TEMPERATURE WAS CONSTANT.
But the VOLUME DECREASED. So there are more air molecules per unit area and hence more FREQUENT collisions with the walls of the pistons.
This causes a pressure INCREAsE.
Post by: Snake on May 25, 2010, 01:40:31 pm
#30=D, this is because electrons go from - to + thus if D is broken electrons will not flow to the other lamps.
#34=C, using Flemings grip rule for this one, you will find the current, and thus the direction of the Magnetic field
#37=A, Anode is always positive(this is to sharpen the image or make it more clear) remember the cathode emits NEGATIVE electrons thus the top Y plate has to be positive for it to move upwards.
Hope it helps Moonlyte :)
Post by: 8T on May 25, 2010, 01:42:14 pm
Post by: holtadit on May 25, 2010, 01:43:11 pm
Thanks A Lot Ari .
Glad I could help :)
Post by: Moonlyte on May 25, 2010, 01:44:11 pm
For # 30 take say 5 for each resistor and remember that in C it is connected in parallel and that u use the equation R=R1*r2 over(divided by)R1+R2
I will check the rest and come back to yew dear :)
ooohhhhh now i get it! Thankss a loott!
Post by: Snake on May 25, 2010, 01:44:24 pm
Q33 P1 Nov/Oct 2008 http://www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Nov/0625_w08_qp_1.pdf
I don't get why it is B?
Post by: holtadit on May 25, 2010, 01:48:06 pm
Ok I only don't understand this from the whole syllabus (excluding some atomic physics stuff)
Q33 P1 Nov/Oct 2008 http://www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Nov/0625_w08_qp_1.pdf
I don't get why it is B?
Ignore the values for the wire and everything else.
CONCENTRATE ON THE COMPONENT !!!!!!
Look at its max current. Got it ? Now select a fuse with a value just a little bit higher than the MAX CURRENT FOR THE COMPONENT
It should be B ;)
Post by: 8T on May 25, 2010, 01:49:13 pm
Snake i do not understand this one ..care to repeat in a different way ?
Post by: Moonlyte on May 25, 2010, 01:51:20 pm
#30=C, This is because resistance in Parallel is always lower then series, this means it has to be be either C or D, however D contains a resistor so its not D and hence it has to be C.
#30=D, this is because electrons go from - to + thus if D is broken electrons will not flow to the other lamps.
#34=C, using Flemings grip rule for this one, you will find the current, and thus the direction of the Magnetic field
#37=A, Anode is always positive(this is to sharpen the image or make it more clear) remember the cathode emits NEGATIVE electrons thus the top Y plate has to be positive for it to move upwards.
Hope it helps Moonlyte :)
thank you very much!
Post by: holtadit on May 25, 2010, 01:53:43 pm
#34=C, using Flemings grip rule for this one, you will find the current, and thus the direction of the Magnetic field
Snake i do not understand this one ..care to repeat in a different way ?
HERE
Click to enlarge
Post by: 8T on May 25, 2010, 01:56:14 pm
Thanks Once again :]
Post by: holtadit on May 25, 2010, 01:58:01 pm
Ari you are so creative in your methods of transferring info.
Thanks Once again :]
I've been here a loooooong time ;)
Post by: Snake on May 25, 2010, 01:58:27 pm
HERE
Click to enlarge
Lol I was trying to explain that, guess pictures speak a thousand words :P
Oh By the way thanks for the help earlier, I finally get this nonsense lol +rep Mate :)
Post by: misterioso on May 25, 2010, 01:58:33 pm
I apologise for the crude picture
Post by: 8T on May 25, 2010, 02:00:39 pm
A year and a half .. how old are you?If I may ask?
Post by: holtadit on May 25, 2010, 02:03:19 pm
I see..
A year and a half .. how old are you?If I may ask?
16 in a few days time, I am doing my IGCSEs :)
Post by: Raywin on May 25, 2010, 02:06:17 pm
Can someone explain to me how the answer is B. I understand it has something to do with the capacitor, but why is it that voltmeter two is zero at all? Wouldnt none of them have become zero? Can anyone explain how the capaciter is working in this circuit???
I apologise for the crude picture
The ans is B. This is cause there is a complete circuit between volt meter 1 and the battery when the switch is opened. And the capacitor will be charging when the switch is closed. When the switch is opened again, it will discharge thus volt.meter 3 will show voltage. Thus these two volt. meters will show some voltage. So ans is B. Hope u got me.. :)
Post by: 8T on May 25, 2010, 02:08:44 pm
Post by: ambitious94 on May 25, 2010, 02:09:57 pm
What are nucleons? Neutrons or all the particles present in the nucleus?
Also
The north pole of a bar magnet is placed next to end P of an iron bar PQ, as shown. As a result,
magnetic poles are induced in the iron bar.
S (magnet) N iron bar-->P Q
What are the magnetic poles induced at P and at Q?
magnetic pole at P magnetic pole at Q
A north north
B north south
C south north
D south south
Answer's C. I dont get it...I thght the N pole induced an N pole....:S
Post by: 8T on May 25, 2010, 02:11:30 pm
& Induction therefore attraction.. N IS ATTRACTED TO P.. And a magnet cannot have 2 north poles or south so the other one is south = C
Post by: rhea on May 25, 2010, 02:12:07 pm
I have a new question XDactually i got a doubt related to this..
What are nucleons? Neutrons or all the particles present in the nucleus?
Also
The north pole of a bar magnet is placed next to end P of an iron bar PQ, as shown. As a result,
magnetic poles are induced in the iron bar.
S (magnet) N iron bar-->P Q
What are the magnetic poles induced at P and at Q?
magnetic pole at P magnetic pole at Q
A north north
B north south
C south north
D south south
Answer's C. I dont get it...I thght the N pole induced an N pole....:S
i always thought to induce magnetism, you have to stroke a magnet with the magnetic material.
Post by: jellybeans on May 25, 2010, 02:13:23 pm
I have a new question XD
What are nucleons? Neutrons or all the particles present in the nucleus?
Also
The north pole of a bar magnet is placed next to end P of an iron bar PQ, as shown. As a result,
magnetic poles are induced in the iron bar.
S (magnet) N iron bar-->P Q
What are the magnetic poles induced at P and at Q?
magnetic pole at P magnetic pole at Q
A north north
B north south
C south north
D south south
Answer's C. I dont get it...I thght the N pole induced an N pole....:S
nope!! when induction occurs , the N pole will induce a S pole on the iron barrrr cuz during induction, the magnet's repelling its same charge to the other side, leaving the surface nearest to N with the 'opposite charge' so P will be south. :)
Post by: holtadit on May 25, 2010, 02:14:32 pm
actually i got a doubt related to this..
i always thought to induce magnetism, you have to stroke a magnet with the magnetic material.
See if this helps.
(http://www.le.ac.uk/se/centres/sci/selfstudy/ps49.gif)
OR read it here if the image's too small :
http://www.le.ac.uk/se/centres/sci/selfstudy/mam9.htm
Post by: Raywin on May 25, 2010, 02:15:10 pm
Raywin ..I didnt.. More explanation please.
Hmm.. see there is a complete circuit between the battery and voltmeter 1 meaning that current will flow from the battery through the voltmeter and then to the battery again. This happens even WHEN THE SWITCH IS OPEN. So, voltmeter 1 will NOT show zero. Now, the capacitor will charge up when the circuit was initially closed and when the switched is opened it will discharge, meaning that current will flow from the capacitor through the voltmeter3 and then to the capacitor again. This makes the voltmeter show a reading. Therefore it WILL NOT SHOW ZERO. Thus voltmeter 2 is the only one tht does show zero. :) Now?
Post by: Burhan.arshad on May 25, 2010, 02:15:58 pm
actually i got a doubt related to this..north pole induce north pole when you hit ot touch it with megnt......but when u just place it near it will induce opposite pole
i always thought to induce magnetism, you have to stroke a magnet with the magnetic material.
Post by: Vin on May 25, 2010, 02:16:37 pm
Can someone explain to me how the answer is B. I understand it has something to do with the capacitor, but why is it that voltmeter two is zero at all? Wouldnt none of them have become zero? Can anyone explain how the capaciter is working in this circuit???
I apologise for the crude picture
pics cool ;) i use w7 too ;)
Post by: Malak on May 25, 2010, 02:17:26 pm
I have a new question XD
What are nucleons? Neutrons or all the particles present in the nucleus?
Also
The north pole of a bar magnet is placed next to end P of an iron bar PQ, as shown. As a result,
magnetic poles are induced in the iron bar.
S (magnet) N iron bar-->P Q
What are the magnetic poles induced at P and at Q?
magnetic pole at P magnetic pole at Q
A north north
B north south
C south north
D south south
Answer's C. I dont get it...I thght the N pole induced an N pole....:S
No The pole is always opposite to that nearest of the permanent manget...In this case P is near to N of permanent magnet so it S
Post by: misterioso on May 25, 2010, 02:21:43 pm
The ans is B. This is cause there is a complete circuit between volt meter 1 and the battery when the switch is opened. And the capacitor will be charging when the switch is closed. When the switch is opened again, it will discharge thus volt.meter 3 will show voltage. Thus these two volt. meters will show some voltage. So ans is B. Hope u got me.. :)
Wow thanks that explains a lot! I thought that the capacitor was the charge for the whole cicuit thats where i was getting confused!!! Now I know that the battery and capacitor were individual circuits
pics cool ;) i use w7 too ;)
Yeah it is isnt it? Its got the sweetness of Vista but the speed of XP. Thanks for all the help, u even made the effort to edit the picture!!!
Post by: Malak on May 25, 2010, 02:23:44 pm
Specifically in this question:
Wouldnt the volume remain same ???
Post by: MasterMath on May 25, 2010, 02:25:53 pm
Thanks
Post by: Vin on May 25, 2010, 02:28:04 pm
Can anyone exaplain me the relation between volume and pressure...Why when the volume decreases the pressure increases?
Specifically in this question:
Wouldnt the volume remain same ???
answer is C ..
Volume is inversely proportional to Pressure .. as pressure increases volume decreases .. or vise versa
k= constant
p = k/V
pV = k
explaining the molecules .. when pressure is applied the molecules come closer hence are 'compressed' so they are reduced in volume
Post by: Moonlyte on May 25, 2010, 02:29:39 pm
Can anyone exaplain me the relation between volume and pressure...Why when the volume decreases the pressure increases?
Specifically in this question:
Wouldnt the volume remain same ???
Volume and pressure are inversely proportional under the same temperatures. So when one increases, the other decreases. When you push the piston in, the space decrease (i.e the volume decreases) and the same no. of molecules move randomly in a smalled volume so pressure increases.
Post by: holtadit on May 25, 2010, 02:31:03 pm
Can anyone exaplain me the relation between volume and pressure...Why when the volume decreases the pressure increases?
Specifically in this question:
Wouldnt the volume remain same ???
Vin and Moonlyte already explained the necessary. BUT the volume WOULD change since the piston moves inwards.
Post by: Snake on May 25, 2010, 02:31:12 pm
Can anyone exaplain me the relation between volume and pressure...Why when the volume decreases the pressure increases?
Specifically in this question:
Wouldnt the volume remain same ???
Volume decrease (becomes smaller) Pressure increase this is because it takes the particles less time to collide with the container wall.
Volume increase (becomes bigger) Pressure decrease this is because it takes the particles more time to collide with the container walls.
No the volume would decrease because he is pushing, so it slides make the volume less and hence increasing pressure!
Hope I helped :)
Post by: guMnam on May 25, 2010, 02:32:17 pm
Post by: Vin on May 25, 2010, 02:32:29 pm
Vin and Moonlyte already explained the necessary. BUT the volume WOULD change since the piston moves inwards.
i hav kinda modified
https://studentforums.biz/index.php/topic,6468.msg224107.html#msg224107
Post by: MasterMath on May 25, 2010, 02:32:56 pm
Post by: Vin on May 25, 2010, 02:34:07 pm
Yeah it is isnt it? Its got the sweetness of Vista but the speed of XP. Thanks for all the help, u even made the effort to edit the picture!!!
tht is wat i like !! :D
LOL, this is nothing .. i;ve done better stuff :P
Post by: Malak on May 25, 2010, 02:34:38 pm
Post by: Snake on May 25, 2010, 02:34:58 pm
okay..now i m confused...wasnt the stroking thing for permanent magnet
Permanent magnets are materials which keep their magnetic properties after being induced. The stroking method is a way to induce a magnet whether it becomes a permanent or temporary!
Post by: holtadit on May 25, 2010, 02:35:15 pm
Can anyone answer me =/ ?
Its up to you, honestly
i hav kinda modified
https://studentforums.biz/index.php/topic,6468.msg224107.html#msg224107
Your theory is wrong. It is the CHANGE in VOLUME that causes a PRESSURE Increase.
You see he is pushing the PISTON INWARDS = Volume decrease. This causes a PRESSURE rise
Post by: MasterMath on May 25, 2010, 02:36:20 pm
Post by: Vin on May 25, 2010, 02:36:30 pm
What should i revise for paper 1 ? ive solved like from 2009-->2003 .. my average marks are 38-40 .. do i need to do till 1996 or revise anything?
Thanks
Also solve 2000 to 2002 ;) .. read you book for specific topics which u lack or find difficult ;) and once read through ALL the chapters ;)
Post by: Snake on May 25, 2010, 02:36:56 pm
Can anyone answer me =/ ?
Just revise some more notes (while relaxing) you've done enough pastpapers. I only did 6 till now, if only I didn't have History on the same day as Physics.
Post by: Snake on May 25, 2010, 02:37:50 pm
Starting from year are you guys solving from?
I went from oct/nov 2009 and worked backwards.
Post by: Snake on May 25, 2010, 02:41:12 pm
Post by: Raywin on May 25, 2010, 02:41:41 pm
Guys do we have to know Rutherford's nuclear model (I think it is the gold foil experiment thing)?
Itll be good if u do noe.. ;)
Post by: Vin on May 25, 2010, 02:42:16 pm
Its up to you, honestly
Your theory is wrong. It is the CHANGE in VOLUME that causes a PRESSURE Increase.
You see he is pushing the PISTON INWARDS = Volume decrease. This causes a PRESSURE rise
Ohh .. i see thanks :) yea Boyle's Law .. i used to think the other way ..
Post by: Raywin on May 25, 2010, 02:42:39 pm
Post by: Kojoudeh95 on May 25, 2010, 02:43:42 pm
Hey guys, doubt. Are water waves longitudinal or tranversal? :S
They are longitudinal :D
Post by: Raywin on May 25, 2010, 02:44:15 pm
They are longitudinal :D
Ryte thx.. ;D
Post by: holtadit on May 25, 2010, 02:45:06 pm
For physics revision check out these links
http://thenightdreamer.wordpress.com/category/subjects/physics-education-archive/
http://thenightdreamer.wordpress.com/category/subjects/physics-education-archive/page/2/
Oh By the way - the above website; belongs to me. ;)
Post by: MasterMath on May 25, 2010, 02:45:33 pm
Post by: holtadit on May 25, 2010, 02:45:43 pm
Hey guys, doubt. Are water waves longitudinal or tranversal? :S
TRANSVERSAL
Post by: Kojoudeh95 on May 25, 2010, 02:45:55 pm
To prevent the cable overheating, how should the cable be changed, and why?
A Use thicker copper cable which has less resistance.
B Use thicker insulation which stops the heat escaping.
C Use thinner copper cable which has more resistance.
D Use thinner insulation which allows less heat to escape.
Post by: Kojoudeh95 on May 25, 2010, 02:46:41 pm
Ryte thx.. ;D
noo man am srry...i just wasnt thinking wen i typed...its transverse srry :D
Post by: Kojoudeh95 on May 25, 2010, 02:47:46 pm
Theyre actually transverse >_< im pretty sure
I just wasnt concentrating wen i typed it...i was like not longtidudinal then i wrote it :P
Post by: Snake on May 25, 2010, 02:48:46 pm
hey guys...can any1 tell me how cables over heat....Too much what causes overheating??? And how to solve this A mains electrical circuit uses insulated copper cable and the cable overheats.
To prevent the cable overheating, how should the cable be changed, and why?
A Use thicker copper cable which has less resistance.
B Use thicker insulation which stops the heat escaping.
C Use thinner copper cable which has more resistance.
D Use thinner insulation which allows less heat to escape.
The answer is A.
Post by: Raywin on May 25, 2010, 02:49:29 pm
TRANSVERSAL
LOL... thx.. :P
Post by: Raywin on May 25, 2010, 02:51:24 pm
noo man am srry...i just wasnt thinking wen i typed...its transverse srry :D
Haha.. its k.. happens.. ;) :P
Post by: diva_sparkles on May 25, 2010, 02:51:42 pm
hey guys...can any1 tell me how cables over heat....Too much what causes overheating??? And how to solve this A mains electrical circuit uses insulated copper cable and the cable overheats.
To prevent the cable overheating, how should the cable be changed, and why?
A Use thicker copper cable which has less resistance.
B Use thicker insulation which stops the heat escaping.
C Use thinner copper cable which has more resistance.
D Use thinner insulation which allows less heat to escape.
its A cos thiCKEr copper cable has less resistance as it is inversely proportional 2 area. N resistance heats da cables so this is how u prevent it frm overheating!!
Post by: Snake on May 25, 2010, 02:52:10 pm
Hey guys, doubt. Are water waves longitudinal or tranversal? :S
Water waves move up and down (oscillate) this is a property of a Transverse Wave.
Longitudinal waves compress and refract (squash and stretch)
Just a lil extra knowledge!
Post by: holtadit on May 25, 2010, 02:56:42 pm
Post by: Baladya on May 25, 2010, 02:57:19 pm
@ Snake +rep :)
dude did u see my message?
Post by: Raywin on May 25, 2010, 02:58:12 pm
Water waves move up and down (oscillate) this is a property of a Transverse Wave.
Longitudinal waves compress and refract (squash and stretch)
Just a lil extra knowledge!
Thanks a lot..! :D
Post by: Snake on May 25, 2010, 03:00:23 pm
@ Snake +rep :)
Thanks mate, By the way great ppt on the gold foil experiment, + rep for it :)
Post by: Kojoudeh95 on May 25, 2010, 03:02:05 pm
Post by: Ghost Of Highbury on May 25, 2010, 03:07:23 pm
Can any1 help me in doin this!!! plZ :D!!! and plz explain indetail :P ;)
say the voltage is 6V
first diagram the 100 ohms (connected to Voltmeter) gets 100/200 * 6 = 3
for the second diagram the 100 ohms gets 100/190 * 6 = 3.15
thus increases a little
Post by: Kojoudeh95 on May 25, 2010, 03:10:03 pm
say the voltage is 6V
first diagram the 100 ohms (connected to Voltmeter) gets 100/200 * 6 = 3
for the second diagram the 100 ohms gets 100/190 * 6 = 3.15
thus increases a little
Thanks alot..i didnt think of it in that way...i just said in both cases its across the 100ohms so stays the same....thaaank youuu!!
:D :D :D ;) + rep :D
Post by: Ghost Of Highbury on May 25, 2010, 03:10:40 pm
Thanks alot..i didnt think of it in that way...i just said in both cases its across the 100ohms so stays the same....thaaank youuu!!
:D :D :D ;) + rep :D
No issues. Good luck with the exam.
Post by: Raywin on May 25, 2010, 03:13:32 pm
Post by: Ghost Of Highbury on May 25, 2010, 03:16:22 pm
Hey guys, i really dont understand the concept of reflective index. :/ can someone explain it to me? :)
any specific question?
Post by: holtadit on May 25, 2010, 03:17:01 pm
go ahead and help these people - I'm gonna take off :)
Post by: Raywin on May 25, 2010, 03:18:07 pm
any specific question?
Oh not really but it might come for mcqs right? :/ i havent seen any so far but i cant really take a chance..
Post by: Ghost Of Highbury on May 25, 2010, 03:23:20 pm
Oh not really but it might come for mcqs right? :/ i havent seen any so far but i cant really take a chance..
theres not much to know abt it, just the formula
ALWAYS formula for refractive index depends from which medium it passes
eg .
From denser to rarer (glass to air) refractive index = sin r /sin i (i - angle of incidence, r - angle of reflection)
From rarer to denser (air to glass refractive index = sin i / sin r
the refractive index is never less than 1, so if ur getting the value of d refractive index < 1..u gotta check for errors..
Post by: Raywin on May 25, 2010, 03:25:31 pm
theres not much to know abt it, just the formula
ALWAYS formula for refractive index depends from which medium it passes
eg .
From denser to rarer (glass to air) refractive index = sin r /sin i (i - angle of incidence, r - angle of reflection)
From rarer to denser (air to glass refractive index = sin i / sin r
the refractive index is never less than 1, so if ur getting the value of d refractive index < 1..u gotta check for errors..
Thanks a lot!! :D and another thing wht is the relationship between the resistance of a wire and its length and diameter?
Post by: rhea on May 25, 2010, 03:25:50 pm
Post by: Raywin on May 25, 2010, 03:28:12 pm
can some1 explain vernier calipers
Its an instrument that is used to measure (accurately) the thickness of something REALLY small like a coin which for example a ruler cannot measure accurately.
Post by: Ghost Of Highbury on May 25, 2010, 03:29:37 pm
Thanks a lot!! :D and another thing wht is the relationship between the resistance of a wire and its length and diameter?
The resistance of the wire is inversely proportional to the diameter, better to say the cross-sectional area and directly proportional to the length;
Post by: Vin on May 25, 2010, 03:30:29 pm
for the first one .. i know its not in the 2010 syllabus i jus wanna know..
fo the 2nd .. i knoe tht the resistance increases in dark but y does pd increase ??..i ve been trying to figure out since long now!
Post by: Raywin on May 25, 2010, 03:30:46 pm
The resistance of the wire is inversely proportional to the diameter, better to say the cross-sectional area and directly proportional to the length;
Thank you once again! :D :D ;D
Post by: igext on May 25, 2010, 03:31:22 pm
In a transformer the induced current in the 2ndry coil also has a mgnetic field right?
then why isnt the current in the primary coil affected?
Post by: rhea on May 25, 2010, 03:31:31 pm
Its an instrument that is used to measure (accurately) the thickness of something REALLY small like a coin which for example a ruler cannot measure accurately.to what dp does it measure?
also can it be used to measure a pipe?
Post by: Adzel on May 25, 2010, 03:36:20 pm
Post by: Ghost Of Highbury on May 25, 2010, 03:37:13 pm
Aadi two ques for you .. either im too dumb or the ms is wrong ..
for the first one .. i know its not in the 2010 syllabus i jus wanna know..
fo the 2nd .. i knoe tht the resistance increases in dark but y does pd increase ??..i ve been trying to figure out since long now!
for the first one : what is the answer , is it B?
for the second, V = I*R
R increases, V increases
thats wat i can think of now.
Post by: Vin on May 25, 2010, 03:41:18 pm
Interesting Question:
In a transformer the induced current in the 2ndry coil also has a mgnetic field right?
then why isnt the current in the primary coil affected?
Induced current is produced when the mag. field from the Primary coils 'cuts' the secondary.
When the current is switched off in the primary the mag field dies away therefore cutting secondary as they collapse inducing a pd into it. tht is why a.c is used
Post by: Vin on May 25, 2010, 03:43:04 pm
for the first one : what is the answer , is it B?
for the second, V = I*R
R increases, V increases
thats wat i can think of now.
ya how B ? y- axis thts y??
but when R increases, doesnt the value of the current in the circuit in the change ??
Post by: Raywin on May 25, 2010, 03:46:46 pm
to what dp does it measure?
also can it be used to measure a pipe?
Hmmm... Vernier calipers can measure internal dimensions (using the uppermost jaws in the picture given), external dimensions using the pictured lower jaws, depth measurements by the use of a probe that is attached to the movable head and slides along the centre of the body. This probe is slender and can get into deep grooves that may prove difficult for other measuring tools.
The vernier scales may include both metric and inch measurements on the upper and lower part of the scale.
Vernier calipers commonly used in industry provide a precision to a hundredth of a millimetre (10 micrometres), or one thousandth of an inch.
A more precise instrument used for the same purpose is the micrometer. I hope this info helps googled it.. ;) check the picture attached..
Post by: 8T on May 25, 2010, 03:48:26 pm
I know that one goes opposite to the other .
Plus,an explanation of total internal reflection is helpful too.
Thanks in advance.
Post by: rhea on May 25, 2010, 03:49:23 pm
split ring commutator
slip ring commutator?
IN DETAIL please?
:-\ :-\ :-\
Post by: Ghost Of Highbury on May 25, 2010, 03:49:59 pm
ya how B ? y- axis thts y??
but when R increases, doesnt the value of the current in the circuit in the change ??
Nah, i dont think it changes..the share of the voltage received decreases.
and abt that. The time base is the x-axis. The a/c current produces the y-axis.
-------- |
| <- only a.c current
only time base |
|
when they combine they form the wave.
Post by: rhea on May 25, 2010, 03:50:57 pm
Hmmm... Vernier calipers can measure internal dimensions (using the uppermost jaws in the picture given), external dimensions using the pictured lower jaws, depth measurements by the use of a probe that is attached to the movable head and slides along the centre of the body. This probe is slender and can get into deep grooves that may prove difficult for other measuring tools.
The vernier scales may include both metric and inch measurements on the upper and lower part of the scale.
Vernier calipers commonly used in industry provide a precision to a hundredth of a millimetre (10 micrometres), or one thousandth of an inch.
A more precise instrument used for the same purpose is the micrometer. I hope this info helps googled it.. ;) check the picture attached..
yes!!
thankyou! ;D ;D ;D ;D
Post by: Vin on May 25, 2010, 03:51:09 pm
spectrum
Post by: Ghost Of Highbury on May 25, 2010, 03:52:42 pm
Is any1 free enough to post for me the electromagnetic spectrum in order of frequency and wavelenth .
I know that one goes opposite to the other .
Plus,an explanation of total internal reflection is helpful too.
Thanks in advance.
high frequency low frequency
short wavelength long wavelength
Gamma ------------- X-Rays ---------- UV ------- Visible Rays -------- Infrared rays ------- Microwaves ------ Radio Waves
Post by: Vin on May 25, 2010, 03:55:25 pm
@ VIN: the resistance is always directly proportional to the P.D...
I thought current is directly proportional to p.d :-\
Post by: Fastal on May 25, 2010, 03:57:36 pm
I thought current is directly proportional to p.d :-\it depends on how you look at it, i think you both are right in some ways
when the resistance of an appliance is hight the potential for that appliance compared to others is high
and if there is one appliance, the higher p.d=higher current
Post by: guMnam on May 25, 2010, 03:58:37 pm
I thought current is directly proportional to p.d :-\yes it is....ohm s law
Post by: holtadit on May 25, 2010, 03:59:27 pm
I thought current is directly proportional to p.d :-\
VOLTAGE is DIRECTLY PROPORTIONAL TO CURRENT.
Only if Resistance is CONSTANT !!!!!
Post by: holtadit on May 25, 2010, 04:00:14 pm
Post by: Ghost Of Highbury on May 25, 2010, 04:00:23 pm
VOLTAGE is DIRECTLY PROPORTIONAL TO CURRENT.
Only if Resistance is CONSTANT !!!!!
And voltage is directly proportional to Resistance if Current is constant
V=I*R
Post by: Ghost Of Highbury on May 25, 2010, 04:01:26 pm
Why is it D and NOT B
B is a possibility , D is certain to happen. Simple.
Post by: Baladya on May 25, 2010, 04:02:04 pm
Why is it D and NOT B
Ya i was going to say that, B is right, but D is more of the right answer :P
Post by: guMnam on May 25, 2010, 04:02:56 pm
Post by: Ivo on May 25, 2010, 04:03:41 pm
Post by: Ivo on May 25, 2010, 04:04:15 pm
okay....if we place a resistor in a circuit ...does the curent decrease...or does the p.d decrease ???
It depends if the circuit is series or parallel.
Post by: holtadit on May 25, 2010, 04:05:22 pm
Can someone please explain the V=I^2R formula, and how this relates to heat loss in electric cables. This is mainly for Paper 3, many thanks in advance.
Firstly, its P=I2R
Post by: guMnam on May 25, 2010, 04:05:41 pm
It depends if the circuit is series or parallel.for example..if it is parallel??
Post by: Ivo on May 25, 2010, 04:08:21 pm
for example..if it is parallel??
Then if V=IR, so re-arrange I=V/R, so V is constant, so if you increase the resistance, then you decrease the current.
Post by: diva_sparkles on May 25, 2010, 04:08:49 pm
Firstly, its P=I2R
it can also be H=I^2R
H is heat in this case
Post by: Malak on May 25, 2010, 04:09:59 pm
thx
Post by: 8T on May 25, 2010, 04:11:06 pm
Post by: Snake on May 25, 2010, 04:11:25 pm
Thanks a lot!! :D and another thing wht is the relationship between the resistance of a wire and its length and diameter?
Length - If length increases (lets say by x2) then the resistance increases by x2 because it takes 2 times the amount of time for the current to travel! (Increase in length=Increase in Resistance)
Crossectional area (diameter) - If the area decreases then resistance increases, however if area increases then resistance decreases ( Decrease in area=Increase in Resistance)
Hope I helped elaborate a bit more :)
Guys I have a doubt, what is a Capacitor? and its properties?
Post by: guMnam on May 25, 2010, 04:12:24 pm
Then if V=IR, so re-arrange I=V/R, so V is constant, so if you increase the resistance, then you decrease the current.so mainly it depends on the equatin..there is no rule??...
Post by: Ivo on May 25, 2010, 04:13:10 pm
Could someone spare his time & explain total internal reflection for me?
TIR happens when angle of incidence (IN OPTICALLY DENSER material) is more than critical angle.
Post by: jellybeans on May 25, 2010, 04:13:17 pm
How do u calculate the answer...
thx
5 hours is 1/4 of 20 hours.
you need to find what is WAS .. so you repeat (0.48*2) for 4 times. this is cuz it was halved for 4 times to reach 0.48, so to find what is was before, you times 2 by 4 times.. eek, geddit? >_<
0.48*2*2*2*2 = 7.68g :)
Post by: Ghost Of Highbury on May 25, 2010, 04:13:29 pm
How do u calculate the answer...
thx
0.48*2*2*2*2 = 7.68
7.68 after 5 hours = 3.84
after 10 hours = 1.92
after 15 hours = 0.96
after 20 hours = 0.48
Post by: Ivo on May 25, 2010, 04:13:48 pm
so mainly it depends on the equatin..there is no rule??...
Yep, kind of.
Post by: holtadit on May 25, 2010, 04:16:25 pm
How do u calculate the answer...
thx
Okay.....
There a FOUR half lives involved in this each FIVE hours long = 20 hours altogether.
Okay, if you knew the ORIGINAL mass (lets say Xg) at the START what would you have done ? X/2= something which you would have divided by 2 and so on.
For this you need to wrk backwards.
0.48*2= 0.96
0.96*2= 1.92
1.92*2= 3.84
3.84*2= 7.68 g
Post by: Ghost Of Highbury on May 25, 2010, 04:16:45 pm
it can also be H=I^2R
H is heat in this case
High voltage direct current (HVDC) is used to transmit large amounts of power over long distances
P = V*I
P is constant, thus, a large value of voltage is used to reduce the current.
H = I^2r
I reduces, H reduces. Thus the heat loss is reduced.
Post by: Raywin on May 25, 2010, 04:17:16 pm
Length - If length increases (lets say by x2) then the resistance increases by x2 because it takes 2 times the amount of time for the current to travel! (Increase in length=Increase in Resistance)
Crossectional area (diameter) - If the area decreases then resistance increases, however if area increases then resistance decreases ( Decrease in area=Increase in Resistance)
Hope I helped elaborate a bit more :)
Guys I have a doubt, what is a Capacitor? and its properties?
THANKS A LOT! YES U DID.. ;D AND A capacitor is something tht looks like this || on a circuit. Wht it does is when connected to a circuit with a switch closed, it charges. Charge is stored in it. When the switch is open, it lets these charges out AFTER a delay and it discharges.
Post by: holtadit on May 25, 2010, 04:19:02 pm
LMAO !
Post by: Snake on May 25, 2010, 04:19:56 pm
THANKS A LOT! YES U DID.. ;D AND A capacitor is something tht looks like this || on a circuit. Wht it does is when connected to a circuit with a switch closed, it charges. Charge is stored in it. When the switch is open, it lets these charges out AFTER a delay and it discharges.
Ah thanks mate +rep ;)
Post by: Raywin on May 25, 2010, 04:22:12 pm
Ah thanks mate +rep ;)
My pleasure.. ;)
Post by: Malak on May 25, 2010, 04:25:12 pm
Post by: 8T on May 25, 2010, 04:26:31 pm
Plus, i would appreciate it if someone could explain q 32 may june 05 p1 .
Thanks Ivo..maybe u could give me a bit more detail? :)
Post by: Baladya on May 25, 2010, 04:27:27 pm
Post by: Snake on May 25, 2010, 04:27:55 pm
Could anyone teach me how you quote in this forum?
Plus, i would appreciate it if someone could explain q 32 may june 05 p1 .
Thanks Ivo..maybe u could give me a bit more detail? :)
To quote click on the quote button on the right top corner of each post.
Can you link the paper please?
Post by: 8T on May 25, 2010, 04:28:38 pm
Post by: holtadit on May 25, 2010, 04:28:59 pm
Could anyone teach me how you quote in this forum?
Plus, i would appreciate it if someone could explain q 32 may june 05 p1 .
Thanks Ivo..maybe u could give me a bit more detail? :)
SEE, click the quote button and a reply screen should open up.
Post by: Baladya on May 25, 2010, 04:29:47 pm
Yes then what it just gives me a grean label "Loading"??
Contact an admin. Its probably an error
Post by: Ghost Of Highbury on May 25, 2010, 04:30:12 pm
Could anyone teach me how you quote in this forum?
Plus, i would appreciate it if someone could explain q 32 may june 05 p1 .
Thanks Ivo..maybe u could give me a bit more detail? :)
C
Coating with zinc will protect it(sacrificial protection) , Painting(will keeep the water and oxygen away)
distilled water(ofcourse not) iron rusts in presence of water and oxygen
Post by: rhea on May 25, 2010, 04:30:30 pm
• The d.c. supply is reversed.
• The coil is turned before switching on, so that P starts on the right and Q on the left.
• The poles of the magnet are reversed.
• The turns on the coil are increased in number.
How many of these changes make the coil rotate in the opposite direction?
A 1
B 2
C 3
D 4
Post by: 8T on May 25, 2010, 04:30:40 pm
Post by: holtadit on May 25, 2010, 04:30:50 pm
Yes then what it just gives me a grean label "Loading"??
Right click the quote button and select OPEN IN NEW TAB
Post by: Snake on May 25, 2010, 04:32:17 pm
Some changes are made, one at a time.
• The d.c. supply is reversed.
• The coil is turned before switching on, so that P starts on the right and Q on the left.
• The poles of the magnet are reversed.
• The turns on the coil are increased in number.
How many of these changes make the coil rotate in the opposite direction?
A 1
B 2
C 3
D 4
C - These 3 (• The d.c. supply is reversed.
• The coil is turned before switching on, so that P starts on the right and Q on the left.
• The poles of the magnet are reversed.)
Post by: Vin on May 25, 2010, 04:32:35 pm
Yes then what it just gives me a grean label "Loading"??
the same happened to the member Moonlyte .. ask her she sorted it out .. ;)
Post by: Baladya on May 25, 2010, 04:33:05 pm
Post by: jellybeans on May 25, 2010, 04:33:26 pm
Post by: rhea on May 25, 2010, 04:33:41 pm
C - These 3 (• The d.c. supply is reversed.
• The coil is turned before switching on, so that P starts on the right and Q on the left.
• The poles of the magnet are reversed.)
Itsays B!!
Post by: Ghost Of Highbury on May 25, 2010, 04:34:51 pm
...help? :P
wats the answer A?
Post by: Snake on May 25, 2010, 04:35:14 pm
Yes sure..http://www.freeexampapers.us/IGCSE/Physics/CIE/2005%20Jun/0625_s05_qp_1.pdf
Its A for Q32 because only that one has a variable resistor allowing it to change/manipulate Voltage! Hope it helps to clear your doubt :)
Post by: jellybeans on May 25, 2010, 04:35:19 pm
wats the answer A?
yepyepyep:)
Post by: holtadit on May 25, 2010, 04:36:21 pm
Ari, i have a problem too. When m writing a reply and i want to 'insert a quote' nothing happens
FIRST select the quote button by right clicking and selecting OPEN IN NEW TAB.
THEN type your message.
Post by: Raywin on May 25, 2010, 04:36:46 pm
...help? :P
Itll be A. Because if waves travel slowly on shallow water, the part of the wavefront NEAR the shallow end would have traveled only a short distance than compared to the rest of the wavefront. This part would be closer to X (as it travels slower) so it is A ... :) Hope u understood.. :)
Post by: diva_sparkles on May 25, 2010, 04:37:12 pm
Its A for Q32 because only that one has a variable resistor allowing it to change/manipulate Voltage! Hope it helps to clear your doubt :)
no its B i checked in ms
Post by: Baladya on May 25, 2010, 04:38:07 pm
FIRST select the quote button by right clicking and selecting OPEN IN NEW TAB.
THEN type your message.
NO, I mean when i press on quote, it works fine, but then if i saw another post (still didnt subit my post) and i want to quote it too i can scroll down and press "insert Quote" but when i press it nothing happens
Post by: ambitious94 on May 25, 2010, 04:39:58 pm
Post by: 8T on May 25, 2010, 04:41:25 pm
Right click the quote button and select OPEN IN NEW TABOh thanks all..
It worked in a new tab :P
Post by: Snake on May 25, 2010, 04:41:50 pm
no its B i checked in ms
Oh ops I didn't see the full picture of B my bad, yea it is B =/ my bad guys!
Post by: jellybeans on May 25, 2010, 04:41:57 pm
Itll be A. Because if waves travel slowly on shallow water, the part of the wavefront NEAR the shallow end would have traveled only a short distance than compared to the rest of the wavefront. This part would be closer to X (as it travels slower) so it is A ... :) Hope u understood.. :)
.... :o sryyyyy my brain isnt really absorbing much atm... so uh sry so why is teh no wait, Xp ummm how does the diagram show where the waves are traveling? D: ......sry
Post by: diva_sparkles on May 25, 2010, 04:42:22 pm
Can anyone pls answer this question? June 2007 Q30. Thanks :)
its B
Post by: ginger on May 25, 2010, 04:43:57 pm
plz help me with this..............Q11 and Q32 nov 2008 paper1.....
urgent plzzzzzzzzz
Post by: ambitious94 on May 25, 2010, 04:44:41 pm
its BThat I figured from the mark scheme....HOWWWWWWW!
Post by: Vin on May 25, 2010, 04:45:16 pm
Some changes are made, one at a time.
• The d.c. supply is reversed.
• The coil is turned before switching on, so that P starts on the right and Q on the left.
• The poles of the magnet are reversed.
• The turns on the coil are increased in number.
How many of these changes make the coil rotate in the opposite direction?
A 1
B 2
C 3
D 4
which paper ?? is there a diag. given ??
Post by: Raywin on May 25, 2010, 04:45:45 pm
.... :o sryyyyy my brain isnt really absorbing much atm... so uh sry so why is teh no wait, Xp ummm how does the diagram show where the waves are traveling? D: ......sry
Lol.. :) the wavefront is shown (the weird line around the X) so where ever any options are NEAREST to this line is the ans.
Post by: MasterMath on May 25, 2010, 04:46:19 pm
Post by: Ghost Of Highbury on May 25, 2010, 04:46:32 pm
its B
yes its B, because its potentiometer. thats how a circuit is drawn with a potentiometer, wait ill get a diagram for u
Post by: jellybeans on May 25, 2010, 04:47:13 pm
Lol.. :) the wavefront is shown (the weird line around the X) so where ever any options are NEAREST to this line is the ans.
ohhh, haha okay. thanks! ;)
Post by: Raywin on May 25, 2010, 04:48:15 pm
ohhh, haha okay. thanks! ;)
Np.. ;)
Post by: MasterMath on May 25, 2010, 04:48:49 pm
Some changes are made, one at a time.Which paper is this? anyone?
• The d.c. supply is reversed.
• The coil is turned before switching on, so that P starts on the right and Q on the left.
• The poles of the magnet are reversed.
• The turns on the coil are increased in number.
How many of these changes make the coil rotate in the opposite direction?
A 1
B 2
C 3
D 4
Post by: holtadit on May 25, 2010, 04:49:02 pm
hay guys
plz help me with this..............Q11 and Q32 nov 2008 paper1.....
urgent plzzzzzzzzz
Q11 = Its dropped from 2m right ? So when it hits the ground some energy will be lost, so it cant bounce up to 2m again can it ? Ofc not.
So it has to be D.
Q32 = see below. THE red arrows represent VERY HIGH CURRENT. Only in once case the fuse blows and protects ALL the lamps.
Post by: Snake on May 25, 2010, 04:49:25 pm
hay guys
plz help me with this..............Q11 and Q32 nov 2008 paper1.....
urgent plzzzzzzzzz
Q11=D, This is because the ball cannot have the same Gravitational Potential energy as it started or more hence it cant be A,B,C.
Q32=D, This is because in A the fuse protects northing, in B only the first lamp, in C only the 2nd lamp, in D it protects both.
Hope it helps :)
Post by: Snake on May 25, 2010, 04:50:17 pm
Post by: red_911 on May 25, 2010, 04:51:00 pm
Post by: 8T on May 25, 2010, 04:52:17 pm
Link:http://www.freeexampapers.us/IGCSE/Physics/CIE/2005%20Jun/0625_s05_qp_1.pdf
Post by: Vin on May 25, 2010, 04:52:28 pm
hay guys
plz help me with this..............Q11 and Q32 nov 2008 paper1.....
urgent plzzzzzzzzz
11) D .. they say energy is "lost" in th form of heat .. so the ball doesnt have that much of energy left to match the original position
remember always a body undergoing a free fall NEVER exceeds its starting position .. here it NEVER exceeds C
32) D again .. ;ets look at A .. fuse in parallel so protects neither of the lamps .. in B only one lamp is protected and also in C only one lamp is protected .. in D the fuse is placed in "beginning" of the circuit so both are protected
Post by: holtadit on May 25, 2010, 04:52:56 pm
i want help in question 16 0625/11/M/J/09 :-X
HiGH THERMAL CAPACITY = SMALL TEMP RISE
LOW THERMAL CAPACITY = LARGE TEMP RISE
Now figure it out ;)
Post by: Vin on May 25, 2010, 04:53:35 pm
No one has explained to me why may june 05 q 32 is B ?
Link:http://www.freeexampapers.us/IGCSE/Physics/CIE/2005%20Jun/0625_s05_qp_1.pdf
https://studentforums.biz/index.php/topic,6468.msg224515.html#msg224515
Post by: Malak on May 25, 2010, 04:54:29 pm
Some changes are made, one at a time.
• The d.c. supply is reversed.
• The coil is turned before switching on, so that P starts on the right and Q on the left.
• The poles of the magnet are reversed.
• The turns on the coil are increased in number.
How many of these changes make the coil rotate in the opposite direction?
A 1
B 2
C 3
D 4
I think its B
Post by: Snake on May 25, 2010, 04:55:46 pm
Post by: red_911 on May 25, 2010, 04:56:52 pm
HiGH THERMAL CAPACITY = SMALL TEMP RISEOHHH...got it ,.. thanks alot ;D ;D
LOW THERMAL CAPACITY = LARGE TEMP RISE
Now figure it out ;)
Post by: Vin on May 25, 2010, 04:57:49 pm
No one has explained to me why may june 05 q 32 is B ?
Link:http://www.freeexampapers.us/IGCSE/Physics/CIE/2005%20Jun/0625_s05_qp_1.pdf
Ok listen .. it is B because its a potentiometer .. if u see the 'arrow' is the contact which can be moved to change the resistance of the circuit hence changing the circuit ..
Post by: Baladya on May 25, 2010, 04:58:10 pm
Post by: Malak on May 25, 2010, 04:59:22 pm
I got bored of studying :S :o :o Cmon man study study only 2 days left before some free time :D
Hehe lol...For me 2 days left before m free completely..just hav to finish phy ::)
Post by: 8T on May 25, 2010, 05:00:23 pm
Help with M 05 q 36? www.freeexampapers.us/IGCSE/Physics/CIE/2005%20Jun/0625_s05_qp_1.pdf
Post by: Baladya on May 25, 2010, 05:00:50 pm
Anyway can u guys explain what is ionising (smth) and what is it used in?
And also plz explain how radioactivity is used in fire alarms
Post by: dodi23 on May 25, 2010, 05:01:49 pm
Post by: Ghost Of Highbury on May 25, 2010, 05:02:39 pm
Thanks for pointing it out :)
Help with M 05 q 36? www.freeexampapers.us/IGCSE/Physics/CIE/2005%20Jun/0625_s05_qp_1.pdf
A - decreases. MAgnets, north and south attract.
Post by: Raywin on May 25, 2010, 05:03:29 pm
A - decreases. MAgnets, north and south attract.
But how do u noe which is north and which is south? :s
Post by: Baladya on May 25, 2010, 05:03:59 pm
lool baladaya...u actually put tht as us sig??
See i dared u xD ;D
Post by: Baladya on May 25, 2010, 05:04:58 pm
But how do u noe which is north and which is south? :s
Current is going from + to -. And so current is gonna go in one side (and this is S) and the come out from (N)
Post by: Raywin on May 25, 2010, 05:06:28 pm
Current is going from + to -. And so current is gonna go in one side (and this is S) and the come out from (N)
Ohh got it.. :) but is tht a rule or something?
Post by: Ghost Of Highbury on May 25, 2010, 05:07:11 pm
But how do u noe which is north and which is south? :s
Check the diagram same post
Post by: diva_sparkles on May 25, 2010, 05:07:50 pm
And also plz explain how radioactivity is used in fire alarms
dont think its in da syllabus!!!
Post by: Baladya on May 25, 2010, 05:09:26 pm
Ohh got it.. :) but is tht a rule or something?
Actually its based on a rule that i cannot explain because its hard and very long. But if anyone can link plz... It has to do with the magnetic effect of a current and how that if two coils are together the magnetic field will interact and bla bla
Post by: Vin on May 25, 2010, 05:09:42 pm
Thanks for pointing it out :)
Help with M 05 q 36? www.freeexampapers.us/IGCSE/Physics/CIE/2005%20Jun/0625_s05_qp_1.pdf
u got 32 right ..??
Q 36) Ok if u see on both the rods the coil is wrapped around is exactly similar so the poles forming on the right side and the left side would be opposite
Post by: Raywin on May 25, 2010, 05:10:16 pm
Check the diagram same post
Ummm.. which hand do v use to find the north out? cause if i use my right hand my thumb points to the left.. O.O
Post by: Baladya on May 25, 2010, 05:12:09 pm
Post by: Vin on May 25, 2010, 05:13:07 pm
Ummm.. which hand do v use to find the north out? cause if i use my right hand my thumb points to the left.. O.O
right hand .. its pointing towards left right .. ??
Post by: diva_sparkles on May 25, 2010, 05:14:52 pm
i call it the flimingo left hand rule ;D
lol its actualy fleming's hand rule
left hand is used to find out the force
right hand to find out current
Post by: Raywin on May 25, 2010, 05:15:11 pm
right hand .. its pointing towards left right .. ??
YEAH! the right hand points to the left. But in tht diagram it says itll point to the right.. :S
Post by: 8T on May 25, 2010, 05:16:06 pm
u got 32 right ..??Yes thanks Both A@di & Vin :]
Q 36) Ok if u see on both the rods the coil is wrapped around is exactly similar so the poles forming on the right side and the left side would be opposite
Post by: Baladya on May 25, 2010, 05:16:30 pm
lol its actualy fleming's hand rule
left hand is used to find out the force
right hand to find out current
REALLYY :o :o I never knew that :S
Post by: Ghost Of Highbury on May 25, 2010, 05:16:49 pm
YEAH! the right hand points to the left. But in tht diagram it says itll point to the right.. :S
[edited]
Post by: jellybeans on May 25, 2010, 05:17:28 pm
Post by: Baladya on May 25, 2010, 05:17:58 pm
lol its actualy fleming's hand rule
left hand is used to find out the force
right hand to find out current
Wait, so for a generator what do we use and for a motor which do we use?
Post by: NidZ- Hero on May 25, 2010, 05:18:28 pm
Post by: Baladya on May 25, 2010, 05:18:53 pm
, hi again; helpppp please? :) :) :)
First one B?
Second D
Post by: jellybeans on May 25, 2010, 05:19:44 pm
First one B?
:( nupes.. first one A, :/
yes, 2nd one's D , ... explanation? :P
Post by: Raywin on May 25, 2010, 05:20:08 pm
Wait, so for a generator what do we use and for a motor which do we use?
Motor ---> left hand rule thingi
Generator ----> Right hand thingi.. :)
Post by: Vin on May 25, 2010, 05:20:13 pm
, hi again; helpppp please? :) :) :)
12) A .. there a vacuum created so pressure is 0
24) A .. all rays are parallel .. so they will emerge through the lens parallel
Post by: Baladya on May 25, 2010, 05:20:40 pm
:( nupes.. first one A, :/
I had a similar question and i still dunno why its zero :S
Second one is D
Post by: jellybeans on May 25, 2010, 05:21:00 pm
12) A .. there a vacuum created so pressure is 0
24) A .. all rays are parallel .. so they will emerge through the lens parallel
24)'s D , thanks for Q12 :) :)
Post by: jellybeans on May 25, 2010, 05:21:26 pm
I had a similar question and i still dunno why its zero :S
Second one is D
hahaha, umm .. cud u explain why it's D pleaaase :P
thankyouus.
Post by: Ghost Of Highbury on May 25, 2010, 05:21:56 pm
12) A .. there a vacuum created so pressure is 0
24) A .. all rays are parallel .. so they will emerge through the lens parallel
C? "CONVERGING" lens...says it all..
Post by: MasterMath on May 25, 2010, 05:22:40 pm
I had a similar question and i still dunno why its zero :SHow is it D .. it should be C .. cause the middle ray which passes through the optical center should pass undeviated so its C >_<
Second one is D
Post by: Vin on May 25, 2010, 05:22:54 pm
Wait, so for a generator what do we use and for a motor which do we use?
LEFT HAND RULE --for MOTORS
LM
RIGHT HAND RULE ---> GENERATORS
RG
Post by: Vin on May 25, 2010, 05:23:56 pm
D? "CONVERGING" lens...says it all..
oh yea .. i see :-[
Post by: Baladya on May 25, 2010, 05:24:14 pm
Post by: MasterMath on May 25, 2010, 05:24:26 pm
D? "CONVERGING" lens...says it all..If you notice the first one doesnt deviate which doent make sense at all so you can exclude that straight forward
Post by: jellybeans on May 25, 2010, 05:24:39 pm
How is it D .. it should be C .. cause the middle ray which passes through the optical center should pass undeviated so its C >_<
MY BAAAAAD! it says C ,, THANKS!!!!!
Post by: Baladya on May 25, 2010, 05:24:47 pm
LEFT HAND RULE --for MOTORS
LM
RIGHT HAND RULE ---> GENERATORS
RG
Thanks
Post by: Ghost Of Highbury on May 25, 2010, 05:25:03 pm
If you notice the first one doesnt deviate which doent make sense at all so you can exclude that straight forward
my bad, its C. center of the lens, psases straight. C
Post by: MasterMath on May 25, 2010, 05:25:41 pm
GUYS. When a ray is going straight (not at an angle) it will continue straight. But when at an angle it will TEND TO GO TOWARDS THE CENTERThat is completly wrong .. all of them deviate .. EXCEPT WHEN IT PASSES THROUGH THE Optical Center they pass through undeviated
im 100% sure!
Post by: Baladya on May 25, 2010, 05:25:48 pm
MY BAAAAAD! it says C ,, THANKS!!!!!
WTF NOOO xD
Post by: jellybeans on May 25, 2010, 05:27:16 pm
WTF NOOO xD
looool sayy whaaaa? O.o
Post by: Weaam on May 25, 2010, 05:27:43 pm
Thank you. ;)
Post by: jellybeans on May 25, 2010, 05:28:00 pm
my bad, its C. center of the lens, psases straight. C
is there a rule?? then whut if its a diverging lens?
Post by: diva_sparkles on May 25, 2010, 05:29:55 pm
is there a rule?? then whut if its a diverging lens?
4 igs u only need 4 converging lens
Post by: jellybeans on May 25, 2010, 05:30:32 pm
4 igs u only need 4 converging lenshahaha serious? lol okayy then .. :P
Post by: MasterMath on May 25, 2010, 05:31:35 pm
is there a rule?? then whut if its a diverging lens?Well heres the rule For any ray parallel to the Optical Axis it will deviate through the optical focus and ANY ray through the optical center
Post by: jellybeans on May 25, 2010, 05:35:03 pm
Well heres the rule For any ray parallel to the Optical Axis it will deviate through the optical focus and ANY ray through the optical center:o :o :o :o :o
lol sry. which one's the optcial axis & which one's the center?? >_<
D:<
Post by: MasterMath on May 25, 2010, 05:36:49 pm
Post by: jellybeans on May 25, 2010, 05:37:47 pm
I dont know if you need to know that , but for my school we dont follow the IGCSE syllabus thats why i take like A level and AS stuff
lol i seee, haha kay then. thaaanks anyways, :) youre taking.. A lvls? O.o
Post by: MasterMath on May 25, 2010, 05:38:13 pm
:o :o :o :o :oGive me a sec ill do a diagram for you.
lol sry. which one's the optcial axis & which one's the center?? >_<
D:<
Post by: Weaam on May 25, 2010, 05:38:20 pm
Post by: MasterMath on May 25, 2010, 05:39:25 pm
lol i seee, haha kay then. thaaanks anyways, :) youre taking.. A lvls? O.oMy school is weird .. we do Physics chem bio O'levels at grade 11 , Grade 10 Computer studies math english arabic and grade 11 we also do AS math then grade 12 we do APs .. its a big load i know but what can i do :D
Post by: Shazizzzle on May 25, 2010, 05:43:41 pm
Post by: jellybeans on May 25, 2010, 05:44:03 pm
Can someone please explain Q 19,29,31,34 O/N 07?
Thank you. ;)
HI- for Q19, its B , cuz steel's the ONLY one that conducts heat out of the four!
Q 31, its B, cuz there are 2 resistors in SERIES and it has the greatest combined resistance so current is reduced
Q 34, its A cuz ... less resistance hence less heat loss (overheating) ...
Post by: jellybeans on May 25, 2010, 05:45:40 pm
My school is weird .. we do Physics chem bio O'levels at grade 11 , Grade 10 Computer studies math english arabic and grade 11 we also do AS math then grade 12 we do APs .. its a big load i know but what can i do :D
AHAHA wow, sounds.. complicated XD LOL but oh well, at least ure learning more stuff than us XD
Post by: MasterMath on May 25, 2010, 05:46:25 pm
:o :o :o :o :oUggh how do i add a picture on my desktop?
lol sry. which one's the optcial axis & which one's the center?? >_<
D:<
Post by: jellybeans on May 25, 2010, 05:48:16 pm
Uggh how do i add a picture on my desktop?
um um um ... to ur desktop? or up here?
if youre talking bout sf then... its right above the "post" and "preview" buttons ... "additional options" ? and attach a fileeee :B
Post by: Vin on May 25, 2010, 05:50:28 pm
Can someone please explain Q 19,29,31,34 O/N 07?
Thank you. ;)
29) C .. always for ohmic conductors the graph is the way shown in the diag. Ohmic conductors are conductors that follow the ohms law .. ohms law states R=V/I .. V is directly proportional to I
Post by: MasterMath on May 25, 2010, 05:51:11 pm
It explains where the Optical Focus is
Post by: Weaam on May 25, 2010, 05:53:29 pm
HI- for Q19, its B , cuz steel's the ONLY one that conducts heat out of the four!
Q 31, its B, cuz there are 2 resistors in SERIES and it has the greatest combined resistance so current is reduced
Q 34, its A cuz ... less resistance hence less heat loss (overheating) ...
For Q34, doesnt the resistance increase with thicker wire?
And thanks! ;)
Post by: Lariemeeva on May 25, 2010, 05:54:01 pm
I have an idea about it but I get so confused and this is by far the only topic that I haven't studied well...
Post by: Vin on May 25, 2010, 05:54:14 pm
black line is the Optical Axis .. green is parallel to it which converges .. am i right Master ??
Post by: jellybeans on May 25, 2010, 05:55:08 pm
For Q34, doesnt the resistance increase with thicker wire?
And thanks! ;)
haha, nopes :D resistance - increase in increasing length of wire & temperature, &decreasing in diameter.
Post by: Shazizzzle on May 25, 2010, 05:57:19 pm
There was this question, Q36 in O/N 2009, P 12 (VARIANT 2).
Post by: jellybeans on May 25, 2010, 05:57:51 pm
And dont laugh at my drawing ... its freehand didnt have time to make it perfect .. tell me if you dont understand it ..
It explains where the Optical Focus is
hahahaha- like your handwriting. THANKS ;D
Post by: Vin on May 25, 2010, 05:58:32 pm
For Q34, doesnt the resistance increase with thicker wire?
And thanks! ;)
29) C .. always for ohmic conductors the graph is the way shown in the diag. Ohmic conductors are conductors that follow the ohms law .. ohms law states R=V/I .. V is directly proportional to I
When the diameter of the wire or the cross sectional area is greater the resistance decreases .. how ?? as the area is increased there is more 'space' for the electrons to move through the wire so not much resistance for them to block their path ..vise versa as the diameter deceases
Post by: MasterMath on May 25, 2010, 05:59:16 pm
(http://support.svi.nl/wikiimg/SA.PNG)Yeah anything parallel to The principle axis Deviates through the principal focus .. and Remember ANYTHING through the center of the lens ( int of y axis and x axis) PASSES through UNDeviated ;)
black line is the Optical Axis .. green is parallel to it which converges .. am i right Master ??
Post by: MasterMath on May 25, 2010, 06:00:31 pm
Post by: Weaam on May 25, 2010, 06:12:54 pm
29) C .. always for ohmic conductors the graph is the way shown in the diag. Ohmic conductors are conductors that follow the ohms law .. ohms law states R=V/I .. V is directly proportional to I
THANK YOOOU!
Post by: guMnam on May 25, 2010, 06:13:57 pm
Yeah anything parallel to The principle axis Deviates through the principal focus .. and Remember ANYTHING through the center of the lens ( int of y axis and x axis) PASSES through UNDeviated ;)is optical focus and principle focus same thing???
Post by: Vin on May 25, 2010, 06:14:42 pm
THANK YOOOU!welcome ..
got the other ones right ?? the resistance in a wire n stuff ??
Post by: Shazizzzle on May 25, 2010, 06:16:47 pm
Post by: diva_sparkles on May 25, 2010, 06:19:28 pm
is optical focus and principle focus same thing???
yup!!
Post by: Vin on May 25, 2010, 06:20:27 pm
Principal axis and Optical Axis are the same ..
Principle Focus : When rays of light are parallel to Principal axis they converge to form Principal Focus
(http://www.antonine-education.co.uk/physics_a2/options/Module_6/Topic_2/ray_diag_6.gif)
Post by: omair on May 25, 2010, 06:25:22 pm
1.revise notes or 2.pastpaper
besttttttt offff luckkkkkkkkk
Post by: NightHawkerr on May 25, 2010, 06:25:47 pm
Thanks :D
Post by: Ghost Of Highbury on May 25, 2010, 06:26:12 pm
Has anyone considered answering MY question?!
i cant open the paper,,
Post by: omair on May 25, 2010, 06:28:40 pm
Can anyone tell me the basic points i need to know about the cathode ray tube? Because there seems to be questions about it in every past papers i've done, and i dont really understand it.dude remember how to find voltage that is voltage gain*amplitude
Thanks :D
and timeperiod that is to multiply timebasewith wave lenth
also make sure u know how to find out y-plates are made more positive up or down to find out where ther beam deflects
Post by: Ivo on May 25, 2010, 06:29:52 pm
Quote
The answer is A, because if thicker wires are used, resistance is less, so current is less, as voltage is constant (I=V/R).
In transformers, for the same power, voltage is increased and so current has decreased, so there is less heat (I=P/V).
Post by: Vin on May 25, 2010, 06:30:25 pm
Has anyone considered answering MY question?!
oh sorry i didnt see urs ..potential difference required for producing cathode rays is really high to produce high energy electrons .. also d.c. is required .. think about it .. u want to produce electrons from the cathode .. if its ac than cathode and anode would constantly be changing ;)
Post by: Ivo on May 25, 2010, 06:31:11 pm
oh sorry i didnt see urs ..potential difference required for producing cathode rays is really high to produce high energy electrons .. also d.c. is required .. think about it .. u want to produce electrons from the cathode .. if its ac than cathode and anode would constantly be changing ;)
FYI, the p.d. you stated is 600V.
Post by: the_grim_reaper on May 25, 2010, 06:34:27 pm
oh sorry i didnt see urs ..potential difference required for producing cathode rays is really high to produce high energy electrons .. also d.c. is required .. think about it .. u want to produce electrons from the cathode .. if its ac than cathode and anode would constantly be changing ;)
hahahaah everyone from our class has a problem with AC and DC. Even I've asked that from VIN. Do you know why we've got a problem with AC and DC??? Cause we never really understood them. Our teacher says AC flows in two directions, DC in 1. (It's correct but not enough).End of story. Nothing else. So VIN, you may find it stupid, but I REALLY need you to please explain the what being AC or DC really means!!! :D
Post by: 8T on May 25, 2010, 06:35:13 pm
I keep getting mixed up with manometers !!
Post by: Ivo on May 25, 2010, 06:36:43 pm
hahahaah everyone from our class has a problem with AC and DC. Even I've asked that from VIN. Do you know why we've got a problem with AC and DC??? Cause we never really understood them. Our teacher says AC flows in two directions, DC in 1. (It's correct but not enough).End of story. Nothing else. So VIN, you may find it stupid, but I REALLY need you to please explain the what being AC or DC really means!!! :D
I think this is it:
AC: alternating current (switches from positive to negative terminal and back to postivie)
DC: direct current (only flows from postivve to negative)
Also, please can someone answer my last post, thanks!
Post by: Ghost Of Highbury on May 25, 2010, 06:37:21 pm
DC - is the unidirectional flow of electric charge
Post by: Ghost Of Highbury on May 25, 2010, 06:38:13 pm
Please can you see if the following is accurate, please also confirm that heat loss is due to increase of current.
Yea heat loss is due to current. H = I^2r...(I^2)!!!
yes, its A, thicker.
Post by: Ivo on May 25, 2010, 06:38:24 pm
Could some1 explain q 13 o/n 03 ?
I keep getting mixed up with manometers !!
The answer is D, because pressure of gas is greater than pressure of air, so the side with gas pushes liquid, so get it? :D
Post by: diva_sparkles on May 25, 2010, 06:38:32 pm
Post by: Ivo on May 25, 2010, 06:39:33 pm
Yea heat loss is due to current. H = I^2r...(I^2)!!!
yes, its A, thicker.
What is H? Never knew that formula.
Post by: Ivo on May 25, 2010, 06:40:36 pm
can sum1 plz tell me y is da anode cool in a CRO
This question came up in s06, so yes, please can someone explain.
Post by: Ghost Of Highbury on May 25, 2010, 06:40:45 pm
H = Heat.
Post by: soraam on May 25, 2010, 06:40:51 pm
Yea heat loss is due to current. H = I^2r...(I^2)!!!is this rule in the syllabus ??????
yes, its A, thicker.
Post by: Vin on May 25, 2010, 06:41:43 pm
FYI, the p.d. you stated is 600V.
i didnt get u ?!? ??? :-[
Post by: diva_sparkles on May 25, 2010, 06:42:37 pm
Its just cooler than the hot cathode
Thanks :)
Post by: Ghost Of Highbury on May 25, 2010, 06:42:44 pm
is this rule in the syllabus ??????
Guyz it is there in the syl..
Electrical Energy Transferred = I2R*t
assuming t = 1
Energy lost as heat energy = I^2r
Post by: soraam on May 25, 2010, 06:42:58 pm
Post by: Ivo on May 25, 2010, 06:43:02 pm
i didnt get u ?!? ??? :-[
I'm just saying the potential difference between cathode and anode is 600V d.c.
Post by: 8T on May 25, 2010, 06:43:15 pm
Post by: Ivo on May 25, 2010, 06:44:26 pm
Its just cooler than the hot cathode
H = Heat.
By the way, is heat of cathode to aid the thermionic emission?
Post by: Ivo on May 25, 2010, 06:44:44 pm
Ivo, uR the best :P
Thank you! 8)
Post by: Vin on May 25, 2010, 06:44:56 pm
Yea heat loss is due to current. H = I^2r...(I^2)!!!
yes, its A, thicker.
same as P = I2R
where P is the power loss due to heat ..
Post by: Ghost Of Highbury on May 25, 2010, 06:45:07 pm
By the way, is heat of cathode to aid the thermionic emission?
Yes
Post by: Ivo on May 25, 2010, 06:46:17 pm
same as P = I2R
where P is the power loss due to heat ..
The reason behind P=(I^2)R:
Combine P=IV and V=IR then you get the above equation!
Post by: Vin on May 25, 2010, 06:47:08 pm
I'm just saying the potential difference between cathode and anode is 600V d.c.
FYI, :P because in the question its 600 V .. rest of the world uses 10,000 to 60,000 V for CROs ;)
Post by: soraam on May 25, 2010, 06:49:54 pm
question 37
i know why its positive but the second part is kinda unreasonable
the answer is C ...
but why??
Post by: Fastal on May 25, 2010, 06:52:20 pm
Post by: soraam on May 25, 2010, 06:53:15 pm
Post by: Shazizzzle on May 25, 2010, 06:55:46 pm
why
What do you mean, 'why'?
In a CRO, it is the CATHODE that is heated, and thus on heating, releases electron beams by thermionic emission.
The anode is just connected to the + power supply to ACCELERATE the electrons.
Post by: soraam on May 25, 2010, 06:57:15 pm
thank you i totaly forgot hoe the CRO is made
Post by: the_grim_reaper on May 25, 2010, 06:59:46 pm
AC - The direction of current periodically reverses , positive to negative, negative to positive, positive to negative...and so on
DC - is the unidirectional flow of electric charge
hahaha you see that's the problem :D. What exactly do you mean by direction??? A current in a wire will flow through the wire right?? It won't exactly change direction and move west or east?? LOL :D.
I think this is it:
AC: alternating current (switches from positive to negative terminal and back to postivie)
DC: direct current (only flows from postivve to negative)
Also, please can someone answer my last post, thanks!
So what i can get from your answer is that say 1 terminal is positive then it becomes negative then again positive and so on... But there's just one problem. Won't it just move backwards and forwards (the current)?? Like one step ahead then 1 step back?? LOL :D.
(Please really sorry to disturb all of you guys but I've never understood this (from Grade 6) and I believe if I don't clear this doubt now, it'll haunt me for the rest of my life)...
Post by: the_grim_reaper on May 25, 2010, 07:02:01 pm
What do you mean, 'why'?
In a CRO, it is the CATHODE that is heated, and thus on heating, releases electron beams by thermionic emission.
The anode is just connected to the + power supply to ACCELERATE the electrons.
"What do you mean, 'why'?" hahahaah cracked me up. Just relax Shaz!!! :D.
Post by: Ghost Of Highbury on May 25, 2010, 07:02:19 pm
hahaha you see that's the problem :D. What exactly do you mean by direction??? A current in a wire will flow through the wire right?? It won't exactly change direction and move west or east?? LOL :D.
So what i can get from your answer is that say 1 terminal is positive then it becomes negative then again positive and so on... But there's just one problem. Won't it just move backwards and forwards (the current)?? Like one step ahead then 1 step back?? LOL :D.
(Please really sorry to disturb all of you guys but I've never understood this (from Grade 6) and I believe if I don't clear this doubt now, it'll haunt me for the rest of my life)...
nonono! haha, look, the current for the first round will move from positive to negative terminal , next, it will move from negative to positive, this keeps on happening..
Post by: holtadit on May 25, 2010, 07:02:48 pm
So please answer this question of mine before I smash the laptop :
Why is it 600 V DC between the cathode and anode of a CRO ???
Specifically WHY DC ?? WHY NOT AC
Post by: WARRIOR on May 25, 2010, 07:05:09 pm
People. I am sleepy, I feel drunk and I really want to go to SLEEEP !!!
So please answer this question of mine before I smash the laptop :
Why is it 600 V DC between the cathode and anode of a CRO ???
Specifically WHY DC ?? WHY NOT AC
dude u cant have alternating POLES for A CRO!!!!!!
do u want the elctrons to keep flyin form one directio another??
no
for DC
U HAVE 1 FIXED NEGATIVE POLE ( CATHODE ) AND ONE ANODE ( POSOTIVE)
ELECTRONS MOVE FROOM NEGATIVE TO POSOTIVE
Post by: Shazizzzle on May 25, 2010, 07:07:23 pm
nonono! haha, look, the current for the first round will move from positive to negative terminal , next, it will move from negative to positive, this keeps on happening..
OOHHHH!
Post by: holtadit on May 25, 2010, 07:08:31 pm
dude u cant have alternating POLES for A CRO!!!!!!
do u want the elctrons to keep flyin form one directio another??
no
for DC
U HAVE 1 FIXED NEGATIVE POLE ( CATHODE ) AND ONE ANODE ( POSOTIVE)
ELECTRONS MOVE FROOM NEGATIVE TO POSOTIVE
Oh *censored* I didnt think about that, I am so tired....
Thanks man - now I can sleep.
GOOD NIGHT AND BEST OF LUCK TO ALL OF YOU !!!!!
Post by: ambitious94 on May 25, 2010, 07:09:27 pm
15 A knife is being sharpened on a rotating sharpening-stone. A spark flies off and lands on the
operator’s hand. The spark is a very hot, very small piece of metal. The operator feels nothing.
What does this show about the piece of metal?
A It has a high thermal capacity.
B It has a low thermal capacity.
C It is a good conductor of heat.
D It is a poor conductor of heat.
Why is it B? :S
and Q31, why does the bulb become brighter? :S
Thanks in advance ;D
Post by: diva_sparkles on May 25, 2010, 07:09:47 pm
dude u cant have alternating POLES for A CRO!!!!!!u can hv alternating current 4 a CRO!!!BUT thts 4 da y n x plates
Post by: Ghost Of Highbury on May 25, 2010, 07:10:36 pm
Oh f**k I didnt think about that, I am so tired....
Thanks man - now I can sleep.
GOOD NIGHT AND BEST OF LUCK TO ALL OF YOU !!!!!
Imma sleep too...Good night guyz. Best of luck.. !!
Post by: 8T on May 25, 2010, 07:12:18 pm
Thanks in advance!
Post by: Malak on May 25, 2010, 07:13:06 pm
dude u cant have alternating POLES for A CRO!!!!!!
do u want the elctrons to keep flyin form one directio another??
lmao..... :D:D
Post by: 6394 on May 25, 2010, 07:14:33 pm
Imma sleep too...Good night guyz. Best of luck.. !!u guyz seepppin lol i gt up nw n will prepare :P :P :P ;D for tom
......gud luk 2 u as wel
Post by: Ghost Of Highbury on May 25, 2010, 07:16:58 pm
u guyz seepppin lol i gt up nw n will prepare :P :P :P ;D for tom
......gud luk 2 u as wel
I have already given my IGCSEs :D
Post by: 6394 on May 25, 2010, 07:17:13 pm
dude u cant have alternating POLES for A CRO!!!!!!rofl
do u want the elctrons to keep flyin form one directio another??
no
for DC
U HAVE 1 FIXED NEGATIVE POLE ( CATHODE ) AND ONE ANODE ( POSOTIVE)
ELECTRONS MOVE FROOM NEGATIVE TO POSOTIVE
i told u!!!!
dat u r a funny teachr :P ;D :D ;)
Post by: Vin on May 25, 2010, 07:17:36 pm
Nov 2005.
15 A knife is being sharpened on a rotating sharpening-stone. A spark flies off and lands on the
operator’s hand. The spark is a very hot, very small piece of metal. The operator feels nothing.
What does this show about the piece of metal?
A It has a high thermal capacity.
B It has a low thermal capacity.
C It is a good conductor of heat.
D It is a poor conductor of heat.
Why is it B? :S
and Q31, why does the bulb become brighter? :S
Thanks in advance ;D
As soon as the metal files off the stone it gets cooled .. hence the person doesnt feel anything .. It has a low thermal capacity meaning looses fast
Post by: 6394 on May 25, 2010, 07:18:57 pm
I have already given my IGCSEs :Dooohkk
lol
so hlpin us haan!!!! :) ;) :D
Post by: 33oomar on May 25, 2010, 07:19:35 pm
q5 paper 1 may/june 2006
Post by: Shazizzzle on May 25, 2010, 07:19:51 pm
Help with O/n 03 q 27 .. ans is B .. WHY ?
Thanks in advance!
It's a steel ball. When a metal such as iron or steel is brought near a magnet, magnetism is INDUCED in it, i.e haphazard domains arrange, and the metal is always ATTRACTED. Thus, the steel ball, which is unmagnetised, will become magnetised, i.e will be ATTRACTED to the N pole.
Post by: The Golden Girl =D on May 25, 2010, 07:20:13 pm
I have already given my IGCSEs :D
r u takin AS or smthn ?
Post by: Vin on May 25, 2010, 07:22:38 pm
Help with O/n 03 q 27 .. ans is B .. WHY ?
Thanks in advance!
ok the steel ball rolled is attracted to the magnet so it deflects upwards .. however u may ask why didnt it 'stick' the magnet .. probably because the ball is pushed with a force which overcomes the strength of the magnetic field ..
Post by: Shazizzzle on May 25, 2010, 07:24:59 pm
ok the steel ball rolled is attracted to the magnet so it deflects upwards .. however u may ask why didnt it 'stick' the magnet .. probably because the ball is pushed with a force which overcomes the strength of the magnetic field ..
Yes, in other words, the force applied in the 'push' is greater than the pull of the magnet, thus it IS ATTRACTED, however continues forward motion, but the attraction creates deviation of path, i.e deflecting in towards the N.
Post by: ambitious94 on May 25, 2010, 07:25:57 pm
As soon as the metal files off the stone it gets cooled .. hence the person doesnt feel anything .. It has a low thermal capacity meaning looses fastThanks VIN, ur a blessing :P =D ;)
Post by: Vin on May 25, 2010, 07:26:28 pm
please help in
q5 paper 1 may/june 2006
Answer is B for the simple reason because umm .. lets start from A .. 1 g, 1 g, 5 g, 10 g .. no matter where u place them 5 g, 10 g spoil the broth :P
B- 1 g, 2 g, 2 g, 5 g .. u can place 1 g, 2 g, 2 g on one side and 5g on the other to balance .. try the others u wont get them ..
Post by: 8T on May 25, 2010, 07:27:54 pm
It's a steel ball. When a metal such as iron or steel is brought near a magnet, magnetism is INDUCED in it, i.e haphazard domains arrange, and the metal is always ATTRACTED. Thus, the steel ball, which is unmagnetised, will become magnetised, i.e will be ATTRACTED to the N pole.
You mentioned that it is attracted to N which means south pole of the ball is attracted..
Main question why not A??
Thanks 4 the effort (:
Post by: Vin on May 25, 2010, 07:28:23 pm
Thanks VIN, ur a blessing :P =D ;)
thanks ;) actually a typo .. i meant.. at the end "looses heat faster" ;)
Post by: the_grim_reaper on May 25, 2010, 07:28:32 pm
nonono! haha, look, the current for the first round will move from positive to negative terminal , next, it will move from negative to positive, this keeps on happening..
hahaha thanks!!!!!!!! U're a life saver. Just 1 final thing, this explains why a capacitor won't charge with AC cause it will prevent accumulation of charges right?? Meaning it will charge and discharge??? And to produce an induced EMF, is it necessary to use an alternating field (the one provided by AC)?? Since DC will not produce an alternating field and no induced EMF right????
Post by: Vin on May 25, 2010, 07:29:41 pm
You mentioned that it is attracted to N which means south pole of the ball is attracted..
Main question why not A??
Thanks 4 the effort (:
See its a metal ball .. it doesnt hav a pole until another magnet 'sticks' to it .. S or N .. doesnt matter for the ball
Post by: Shazizzzle on May 25, 2010, 07:31:49 pm
You mentioned that it is attracted to N which means south pole of the ball is attracted..
Main question why not A??
Thanks 4 the effort (:
See, the ball is UNMAGNETISED.
When it is exposed to N of magnet, that side automatically gains the S pole.
Thus, it ATTRACTS to the North.
In A, however, the ball is deflect downwards. That would mean it is repelling, which it is NOT.
Unlike poles attract!
Post by: 33oomar on May 25, 2010, 07:33:46 pm
Answer is B for the simple reason because umm .. lets start from A .. 1 g, 1 g, 5 g, 10 g .. no matter where u place them 5 g, 10 g spoil the broth :P
B- 1 g, 2 g, 2 g, 5 g .. u can place 1 g, 2 g, 2 g on one side and 5g on the other to balance .. try the others u wont get them ..
Oh i got it now :-\
Thanks a lot Homie
Post by: Vin on May 25, 2010, 07:34:58 pm
hahaha thanks!!!!!!!! U're a life saver. Just 1 final thing, this explains why a capacitor won't charge with AC cause it will prevent accumulation of charges right?? Meaning it will charge and discharge??? And to produce an induced EMF, is it necessary to use an alternating field (the one provided by AC)?? Since DC will not produce an alternating field and no induced EMF right????
ok u said "a capacitor won't charge with AC cause it will prevent accumulation of charges right??" PERFECT!
" Meaning it will charge and discharge" i dont think it will charge on the first place because the to and fro is so fast tht the capacitor wont be able to have enough time to get charged .. ;)
" And to produce an induced EMF, is it necessary to use an alternating field (the one provided by AC)?? Since DC will not produce an alternating field and no induced EMF right????" yup this is right .. do you know WHY ac is needed for induced pd ??
Post by: 8T on May 25, 2010, 07:36:21 pm
See, the ball is UNMAGNETISED.oH.. I didnt know it automatically gains S pole .
When it is exposed to N of magnet, that side automatically gains the S pole.
Thus, it ATTRACTS to the North.
In A, however, the ball is deflect downwards. That would mean it is repelling, which it is NOT.
Unlike poles attract!
Many Thanks.
Post by: 6394 on May 25, 2010, 07:37:22 pm
my txt bk says dat capacitor will nt wrk wid dc n will wrk wid ac
hahaha thanks!!!!!!!! U're a life saver. Just 1 final thing, this explains why a capacitor won't charge with AC cause it will prevent accumulation of charges right?? Meaning it will charge and discharge??? And to produce an induced EMF, is it necessary to use an alternating field (the one provided by AC)?? Since DC will not produce an alternating field and no induced EMF right????
<Cambridge IGCSE Physics- Tom DUncun pg 196 :P :P :P :P lol>
Post by: 8T on May 25, 2010, 07:37:35 pm
See its a metal ball .. it doesnt hav a pole until another magnet 'sticks' to it .. S or N .. doesnt matter for the ballThanks 4 the effort .. I get it Now (:
Post by: igext on May 25, 2010, 07:37:58 pm
Post by: Helium on May 25, 2010, 07:39:27 pm
Question, can anyone solve and scan ,
or at least explain how to do it, (dont worry i'll understand)
Post by: igext on May 25, 2010, 07:40:56 pm
the resultant of these 2 forces is actually the weight of the box or wht ever being lifted
Question, can anyone solve and scan ,
or at least explain how to do it, (dont worry i'll understand)
Post by: the_grim_reaper on May 25, 2010, 07:41:16 pm
can some one tell me what is the purpose of the core in a transformer?
It is there to prevent leaking of the alternating field which will produce a strong induced EMF, without it, not all of the alternating field (which should induce an alternating EMF) will reach the other wire so a weaker EMF will be induced.
Correct right??? Please correct me if I'm wrong....
Post by: Vin on May 25, 2010, 07:42:06 pm
can some one tell me what is the purpose of the core in a transformer?
the voltage induces in the core itself .. without it the transformer wouldnt work ..
Post by: igext on May 25, 2010, 07:42:13 pm
It is there to prevent leaking of the alternating field which will produce a strong induced EMF, without it, not all of the alternating field (which should induce an alternating EMF) will reach the other wire so a weaker EMF will be induced.hmm not rlly clear
Correct right??? Please correct me if I'm wrong....
Post by: Vin on May 25, 2010, 07:42:55 pm
Question, can anyone solve and scan ,
or at least explain how to do it, (dont worry i'll understand)
gimme some time ;)
Post by: Vin on May 25, 2010, 07:43:22 pm
hmm not rlly clear
https://studentforums.biz/index.php/topic,6468.msg225034.html#msg225034
Post by: Shazizzzle on May 25, 2010, 07:43:38 pm
can some one tell me what is the purpose of the core in a transformer?
The core is mainly made of iron, A CONDUCTOR, and so, serves as the purpose of CONDUCTING or TRANSFERRING the current from the primary coil to the secondary. It helps with the electromagnetic induction. As a conductor, to allow and speed up the transfer of current process, and it itself is induced.
The core is also made of pieces which are joint via lamination, and not just one whole piece, to avoid building up of eddy current.
Post by: igext on May 25, 2010, 07:44:17 pm
the voltage induces in the core itself .. without it the transformer wouldnt work ..my teacher said the current is directly induced in the 2ndry coil with out the help of the core
Post by: Adzel on May 25, 2010, 07:45:24 pm
Post by: the_grim_reaper on May 25, 2010, 07:45:46 pm
ok u said "a capacitor won't charge with AC cause it will prevent accumulation of charges right??" PERFECT!
" Meaning it will charge and discharge" i dont think it will charge on the first place because the to and fro is so fast tht the capacitor wont be able to have enough time to get charged .. ;)
" And to produce an induced EMF, is it necessary to use an alternating field (the one provided by AC)?? Since DC will not produce an alternating field and no induced EMF right????" yup this is right .. do you know WHY ac is needed for induced pd ??
THanks!!! Ummm since only AC can produce an alternating magnetic field only that can produce an induced EMF?? Lenz's law says that the direction of the induced EMF should be to oppose the change causing it so the field by DC will not induce an EMF since it won't oppose the change causing it?? HAHAHAHAHAHAH LOL. I don't know :D.
Post by: 33oomar on May 25, 2010, 07:48:29 pm
question 39 may/june 2007 paper 1
Please help meeeeee :(
Post by: igext on May 25, 2010, 07:50:40 pm
Guys.. I need help in20 hours means 4 half lives so double the value present now 4 times ( x2 x2 x2 x2 )
question 39 may/june 2007 paper 1
Please help meeeeee :(
Post by: Vin on May 25, 2010, 07:51:25 pm
see attached...
ok so density = mass/volume
in the diag . the initial volume if 100 cc after pouring the liquid its 140 to mass of water = 140 - 100 = 40 cc
volume on diag is 60 cc
density = mass/volume
=40/60
Post by: Vin on May 25, 2010, 07:52:10 pm
my teacher said the current is directly induced in the 2ndry coil with out the help of the core
nop .. not possible ..
Post by: igext on May 25, 2010, 07:53:18 pm
nop .. not possible ..now there is an alternating field due to the 2ndry coil? why duznt this affect the current in primary coil?
Post by: Shazizzzle on May 25, 2010, 07:54:02 pm
Guys.. I need help in
question 39 may/june 2007 paper 1
Please help meeeeee :(
The half-life is 5 hours. That means it takes 5 hours for half the sample to decay.
They are asking about 20 hours before.
After the 20 hours, it was 0.48 g.
How much was it 5 hours before? It would be double, as 5 hours is the half life.
So, 0.48 X 2= 0.96.
0.96 was 5 hours before.
What about ten hours before the initial?
That would be double of the 5 hours before one. i.e 0.96 X 2 = 1.92.
So, 10 hours ago, it was 1.92.
What about 15 hours before? That would be 5 more behind the 10 hours one.
So, 1.92 X 2 = 3.84
And thus for 20, 3.84 X 2 = 7.68
See, in every 5 hours, it doubles.
You can't just multiply 0.48 by 4.
It DOUBLES every 5 HOURS.
So, you have to double it, in each step, when going backwards.
Post by: haris94 on May 25, 2010, 07:54:24 pm
my teacher said the current is directly induced in the 2ndry coil with out the help of the core
thats not true
Post by: CatAly$t on May 25, 2010, 07:54:44 pm
and any tips....
Post by: the_grim_reaper on May 25, 2010, 07:55:49 pm
The half-life is 5 hours. That means it takes 5 hours for half the sample to decay.
They are asking about 20 hours before.
After the 20 hours, it was 0.48 g.
How much was it 5 hours before? It would be double, as 5 hours is the half life.
So, 0.48 X 2= 0.96.
0.96 was 5 hours before.
What about ten hours before the initial?
That would be double of the 5 hours before one. i.e 0.96 X 2 = 1.92.
So, 10 hours ago, it was 1.92.
Shaz don't get mad but the answer is 7.68 g :D
What about 15 hours before? That would be 5 more behind the 10 hours one.
So, 1.92 X 2 = 3.84
And thus for 20, 1.92 X 2 = 3.84
See, in every 5 hours, it doubles.
You can't just multiply 0.48 by 4.
It DOUBLES every 5 HOURS.
So, you have to double it, in each step, when going backwards.
Shaz don't get mad but it's 7.68 g :D.
Post by: Malak on May 25, 2010, 07:56:07 pm
Post by: igext on May 25, 2010, 07:56:45 pm
thats not truearyt... so if they ask about the function of the core worth 2 marks wat will u write down?
Post by: omair on May 25, 2010, 07:56:56 pm
Post by: Adzel on May 25, 2010, 07:57:24 pm
ok so density = mass/volume
in the diag . the initial volume if 100 cc after pouring the liquid its 140 to mass of water = 140 - 100 = 40 cc
volume on diag is 60 cc
density = mass/volume
=40/60
Ohh I thought it was a + sign, and I didn't relize that it is a / sign...lol
Post by: the_grim_reaper on May 25, 2010, 07:57:37 pm
aryt... so if they ask about the function of the core worth 2 marks wat will u write down?
They won't cause it's paper 1 tomorrow :D :D.
Post by: diva_sparkles on May 25, 2010, 07:58:13 pm
Do we need to know the logic gates stuff for ppr 1?
nvr saw thm but just learn it in case it appears!!
Post by: 8T on May 25, 2010, 07:58:54 pm
Ans is B but i chose A .. Why is it the way it is?
Post by: Adzel on May 25, 2010, 07:59:10 pm
any one can u tell me how to find the needle compss deflection when place near stright conductor
(http://1.bp.blogspot.com/_PyvjcvYfRLk/SFnpDI55a4I/AAAAAAAAAEQ/hiFS_Z2Nwk0/s400/Right-Hand-Grip-Rules.png)
Post by: igext on May 25, 2010, 07:59:12 pm
They won't cause it's paper 1 tomorrow :D :D.ya but for ppr 3
Post by: haris94 on May 25, 2010, 08:00:26 pm
Do we need to know the logic gates stuff for ppr 1?
i havent seen any logic gates in p1 for 10 years
but then again.....cant take chances.......so i say learn it incase
Post by: igext on May 25, 2010, 08:00:52 pm
nvr saw thm but just learn it in case it appears!!they wont appear!! paper 1 is a core paper not extended and the core duznt include the logic gates ! look at ur syll
Post by: igext on May 25, 2010, 08:01:43 pm
i havent seen any logic gates in p1 for 10 yearsthey wont appear!! paper 1 is a core paper not extended and the core duznt include the logic gates ! look at ur syll
but then again.....cant take chances.......so i say learn it incase
Post by: Adzel on May 25, 2010, 08:02:15 pm
Folks..Anyone could assist me withMay 07 q 27 ??
Ans is B but i chose A .. Why is it the way it is?
NORTH to SOUTH
(http://www.magnetic-shield.com/images/faq/flux-images.jpg)
Post by: ambitious94 on May 25, 2010, 08:02:24 pm
my txt bk says dat capacitor will nt wrk wid dc n will wrk wid acI checked it out. What is actually means is that current FLOWS thru the circuit with ac and capacitors, not whether it charges or discharges
<Cambridge IGCSE Physics- Tom DUncun pg 196 :P :P :P :P lol>
dc charges it, that's y it blocks the current, as it's gettin charged.
At least that's what I understood. :P The case is open for argument :P ;D
Post by: diva_sparkles on May 25, 2010, 08:03:41 pm
they wont appear!! paper 1 is a core paper not extended and the core duznt include the logic gates ! look at ur syll
isnt it core n extended cos i did see many questions of extended syllabus 2!! :P
Post by: ambitious94 on May 25, 2010, 08:06:35 pm
C in a compass, is the needle a magnet, or is like a soft magnet, gets temporarily magnetized wen it's in a field?
N the plotting compass, does it point at the north pole, or north to south? :S
Would appreciate it if someone wud clarify :)
Post by: Vin on May 25, 2010, 08:08:50 pm
Shaz don't get mad but it's 7.68 g :D.
but u got it how to do it right ??
Post by: Helium on May 25, 2010, 08:10:24 pm
i havent seen any logic gates in p1 for 10 years
but then again.....cant take chances.......so i say learn it incase
its not required in core, and yes i agree don't take any chances :)
Post by: Adzel on May 25, 2010, 08:11:23 pm
Heyy..I'm confused with the whole plotting compass thing...
C in a compass, is the needle a magnet, or is like a soft magnet, gets temporarily magnetized wen it's in a field?
N the plotting compass, does it point at the north pole, or north to south? :S
Would appreciate it if someone wud clarify :)
(http://www.utm.edu/staff/cerkal/magnetic_files/image004.jpg)
OR
(http://www.scienceteacherprogram.org/physics/Omoloju04_files/image002.jpg)
Post by: Helium on May 25, 2010, 08:11:45 pm
gimme some time ;)No prob
take ur time ;D
Thanks
Post by: igext on May 25, 2010, 08:12:21 pm
isnt it core n extended cos i did see many questions of extended syllabus 2!! :Pno way... check again
Post by: Shazizzzle on May 25, 2010, 08:12:27 pm
Heyy..I'm confused with the whole plotting compass thing...
C in a compass, is the needle a magnet, or is like a soft magnet, gets temporarily magnetized wen it's in a field?
N the plotting compass, does it point at the north pole, or north to south? :S
Would appreciate it if someone wud clarify :)
The plotting compass points in the direction of the field lines.
Field lines flow from North to South.
The compass points from the North TO the south.
i.e it points in the direction of the field lines.
TOWARDS south, from NORTH.
That's what the MCQs indicate.
Post by: the_grim_reaper on May 25, 2010, 08:13:42 pm
but u got it how to do it right ??
Oh yeah yeah I know how to do this, By the way, is my answer correct? (To your question?) I mean the one you asked from me.
Post by: Naruto123 on May 25, 2010, 08:14:40 pm
Post by: Shazizzzle on May 25, 2010, 08:15:09 pm
That was a typo. :P
I wrote 1.92 X 2 = 3.84 before, I wrote it again for 20 hours, whereas I should've taken 3.84 X 2 for 20 hours.
Anyways, post edited! :P
Post by: Vin on May 25, 2010, 08:15:39 pm
Folks..Anyone could assist me withMay 07 q 27 ??
Ans is B but i chose A .. Why is it the way it is?
(http://www.school-for-champions.com/science/images/magnetic_detection-compass.gif)
Post by: The Golden Girl =D on May 25, 2010, 08:16:59 pm
VIN , did u kill chem ppr 1 ? ::)
Post by: Ghost Of Highbury on May 25, 2010, 08:17:10 pm
may june 09 ppr 1 variant 1 ques 34ok try this, make ur fingers as shown in the diagram...the way the fingers are wrapped around show how the magnetic lines will be...
check the diagram..check the red arrows which indicate the magnetic field an and direction..
only the red arrow near C matches the compass arrow..
I AM BACK! COULDN't SLEEP! :P
Post by: $H00t!N& $t@r on May 25, 2010, 08:17:43 pm
i always get confused with such stuff. ive seen it in many past papers. how do you know if the waves will refract or not and whether the wavelength will vary???
Post by: 8T on May 25, 2010, 08:18:25 pm
(http://www.school-for-champions.com/science/images/magnetic_detection-compass.gif)You trapped me ..I got it (:
Thanks Dude xD
Post by: Adzel on May 25, 2010, 08:18:50 pm
may june 09 ppr 1 variant 1 ques 34
Post by: Ghost Of Highbury on May 25, 2010, 08:20:36 pm
someone plz explain to me june 2003 Q 24
VIN , did u kill chem ppr 1 ? ::)
B - sound wave longitudinal wave..Longitudinal waves are waves that have the same direction of vibration along their direction of travel
Post by: WARRIOR on May 25, 2010, 08:21:53 pm
need help with m/j 2006 q21first of all FREQUENCY NEVER CHANGES.
i always get confused with such stuff. ive seen it in many past papers. how do you know if the waves will refract or not and whether the wavelength will vary???
speed adn wavelength only changes whn somethin gets refracted
the speed slows down and wavelength decreases if ur goin to a deneser medium and the opposite happens if ur goin to a less dese medium
REMEMBER DEEP WATER : FAST SHALLOW WATER = SLOW
in this case answer is defntly B
and the wave move straing caz angle of incidence is along the normal..pretend the reflractive surface is a miror
Post by: Ivo on May 25, 2010, 08:24:16 pm
first of all FREQUENCY NEVER CHANGES.
speed adn wavelength only changes whn somethin gets refracted
the speed slows down and wavelength decreases if ur goin to a deneser medium and the opposite happens if ur goin to a less dese medium
REMEMBER DEEP WATER : FAST SHALLOW WATER = SLOW
in this case answer is defntly B
and the wave move straing caz angle of incidence is along the normal..pretend the reflractive surface is a miror
An explanation to why frequency is the same: do colour of the waves change when going from deep to shallow water and back? Think!
Post by: The Golden Girl =D on May 25, 2010, 08:25:03 pm
B - sound wave longitudinal wave..Longitudinal waves are waves that have the same direction of vibration along their direction of travel
still didn't get it :-[ ???
Post by: Ivo on May 25, 2010, 08:25:32 pm
Post by: Ivo on May 25, 2010, 08:26:49 pm
still didn't get it :-[ ???
The vibrations of particles are to and fro are parallel to wave direction. The vibrations of particles are up and down perpendicular to wave direction. Get it?
Post by: Helium on May 25, 2010, 08:27:47 pm
the resultant of these 2 forces is actually the weight of the box or wht ever being lifted
ok so after drawing it for example with a scale 1 cm=2N
I just have to measure T3 to find the resultant force, like u said weight of the box.
say yes to confrim.
Post by: WARRIOR on May 25, 2010, 08:28:50 pm
still didn't get it :-[ ???
vibration is along the direction <--> ( vibration )
------------------> ( direction)
you kno sound particles move forward and backward! so vibration is along the direction
opposite to transverse waves. 90 * to direction
^
i dont have and arrow pointi down lol
--------------------------------------->
Post by: Adzel on May 25, 2010, 08:28:59 pm
Guys, this is really confusing for me: describe and explain the function of a 'split ring' commutator in an electric motor.
It helps in contact of the coil and the rotation every half turn. Got it?...
Post by: Ivo on May 25, 2010, 08:29:23 pm
Thanks in advance, your help is appreciated.
Post by: Ghost Of Highbury on May 25, 2010, 08:29:43 pm
still didn't get it :-[ ???The particle vibrates to and fro in the same direction as the wave direction..
Wave -------------------------->>>>
<--particle-->
here : http://paws.kettering.edu/~drussell/Demos/waves/wavemotion.html (the extreme left particles)
check how a single particle vibrates..
Post by: WARRIOR on May 25, 2010, 08:32:00 pm
Also, how do we describe the motor effect? Do we say, if there is a current carrying wire, it causes a field, this interacts with the magnetic field, producing a force which is perpendicular to both the field of wire and magnetic field, according to FLHR.
Thanks in advance, your help is appreciated.
YOU SAY
CURRENT passes 90 * to MAGNETIC FIELD ...A FORCE IS OCCURED TO THE WIRE
but yeah what u said is perfect
Post by: The Golden Girl =D on May 25, 2010, 08:33:19 pm
The particle vibrates to and fro in the same direction as the wave direction..
Wave -------------------------->>>>
<--particle-->
here : http://paws.kettering.edu/~drussell/Demos/waves/wavemotion.html (the extreme left particles)
check how a single particle vibrates..
thx mate ::)
Post by: $H00t!N& $t@r on May 25, 2010, 08:36:56 pm
and the wave move straing caz angle of incidence is along the normal..pretend the reflractive surface is a mirorum.. i dont get this part :-[
@Ivo: good example ;)
Post by: the_grim_reaper on May 25, 2010, 08:39:11 pm
Post by: Shazizzzle on May 25, 2010, 08:40:11 pm
You guys are Physics doubts? :P
Post by: WARRIOR on May 25, 2010, 08:40:25 pm
um.. i dont get this part :-[
@Ivo: good example ;)
wave move in a straight * line caz the engle of incidence is along the normal ( 0 * )
when you come to do other questions like this . Pretened its a recatngle block mirror and you know how the arrow refracts when it enters the block refracts towards the normal?? ya same thing
Post by: Vin on May 25, 2010, 08:41:37 pm
ok so after drawing it for example with a scale 1 cm=2N
I just have to measure T3 to find the resultant force, like u said weight of the box.
say yes to confrim.
sorry for the delay man ! :\
Post by: The Golden Girl =D on May 25, 2010, 08:42:22 pm
Post by: WARRIOR on May 25, 2010, 08:44:05 pm
sorry for the delay man ! :\
gr8 work man !! keep it up
+ rep ! u deserve it !
Post by: Shazizzzle on May 25, 2010, 08:44:59 pm
Q33 year june 2004
A.
The longer vertical bar in a battery represents the +ve, and, from left to right, the terminals are -, +, -, +. A shows that.
also, it is just one loop, so series.
Post by: Ghost Of Highbury on May 25, 2010, 08:46:02 pm
Q33 year june 2004
A - batteries in series, switch and bulb.
Post by: Helium on May 25, 2010, 08:46:17 pm
sorry for the delay man ! :\
No delay, it's veryyy good. ;D
thank you sooo much for your effort.
At lasssssssssssst i get it. A good explantion.
Post by: The Golden Girl =D on May 25, 2010, 08:46:45 pm
A.
The longer vertical bar in a battery represents the +ve, and, from left to right, the terminals are -, +, -, +. A shows that.
also, it is just one loop, so series.
sa7 ;) (i.e right :D)
thx A@di ;D
Post by: $H00t!N& $t@r on May 25, 2010, 08:48:18 pm
wave move in a straight * line caz the engle of incidence is along the normal ( 0 * )ahhh i get it. Thanks ;)
when you come to do other questions like this . Pretened its a recatngle block mirror and you know how the arrow refracts when it enters the block refracts towards the normal?? ya same thing
Post by: The Golden Girl =D on May 25, 2010, 08:49:26 pm
A - batteries in series, switch and bulb.
A@di ,what do u suggest i do , cuz it's really late over here , and iwanna Ace paper 1 physics (By the way i took a revision session a few hours ago with my study group)
thx in advance
Post by: Shazizzzle on May 25, 2010, 08:49:38 pm
sa7 ;) (i.e right :D)
thx A@di ;D
Ana ma3loom. :P
Post by: Ghost Of Highbury on May 25, 2010, 08:51:51 pm
A@di ,what do u suggest i do , cuz it's really late over here , and iwanna Ace paper 1 physics (By the way i took a revision session a few hours ago with my study group)
thx in advance
It seems you still haven't got your concepts right. Try to read your book alone and understand the difficult topics. Its actually very late, but you can go ahead with solving papers. Good luck!
Post by: The Golden Girl =D on May 25, 2010, 08:53:16 pm
It seems you still haven't got your concepts right. Try to read your book alone and understand the difficult topics. Its actually very late, but you can go ahead with solving papers. Good luck!
really ?! ???....well i'll do my best ,and leave the rest to god .....
thx ;)
Post by: The Golden Girl =D on May 25, 2010, 08:53:51 pm
Ana ma3loom. :P
lol...if u wana talk arabic talk here
https://studentforums.biz/index.php/topic,8003.msg225281.html#msg225281
Post by: Ghost Of Highbury on May 25, 2010, 08:54:42 pm
really ?! ???....well i'll do my best ,and leave the rest to god .....
thx ;)
Solving papers is the best option now, hope there are a lotta similar Qs tomorrow.
Post by: CatAly$t on May 25, 2010, 08:55:40 pm
does anybody have a list of formulas for physics??
and any tips....
anybody??
Post by: The Golden Girl =D on May 25, 2010, 08:55:59 pm
Solving papers is the best option now, hope there are a lotta similar Qs tomorrow.
man u kno how to cheer me up :P
thx ...... will do Sir :P
Post by: Vin on May 25, 2010, 08:57:33 pm
does anybody have a list of formulas for physics??
and any tips....
anybody??does anybody have a list of formulas for physics??
and any tips....
made by a member called Imran ;)
Post by: guMnam on May 25, 2010, 08:59:24 pm
Post by: The Golden Girl =D on May 25, 2010, 09:00:25 pm
made by a member called Imran ;)
i think i heard of him ..thx ;)
Post by: guMnam on May 25, 2010, 09:01:08 pm
Post by: guMnam on May 25, 2010, 09:01:34 pm
Post by: guMnam on May 25, 2010, 09:02:27 pm
Post by: Ghost Of Highbury on May 25, 2010, 09:04:31 pm
wen the speed of A WAVE increases the wavelength increases..and no efect on frequency rite ???
Speed = Frequency * Wavelength.
Speed increases, wavelength increases. Frequency doesnt change. Right.
Post by: The Golden Girl =D on May 25, 2010, 09:04:40 pm
Post by: Ghost Of Highbury on May 25, 2010, 09:05:52 pm
and wats the diference between difractioin and refraction
http://csep10.phys.utk.edu/astr162/lect/light/ref-diff.html
Post by: guMnam on May 25, 2010, 09:06:03 pm
Post by: guMnam on May 25, 2010, 09:06:47 pm
Post by: Ghost Of Highbury on May 25, 2010, 09:07:52 pm
Q10 November 2004
A - lowest point , simple.
Post by: The Golden Girl =D on May 25, 2010, 09:09:31 pm
A - lowest point , simple.
oh ya the mgh equation ,k ::)
Post by: guMnam on May 25, 2010, 09:15:48 pm
Post by: Vin on May 25, 2010, 09:21:00 pm
oct nov 2007 p1 q 16,17 how???
16) Its quite obvious that B shows the largest temperature change as it is the smallest !
17) B .. heating the iron (or any metal) results in expansion .. this is easy to fit over the wooden spokes, as it is cooled it fits perfectly over the wood
Post by: guMnam on May 25, 2010, 09:22:33 pm
16) Its quite obvious that B shows the largest temperature change as it is the smallest !i didnt get 16.....if temp increases it should expand and it should become larger
17) B .. heating the iron (or any metal) results in expansion .. this is easy to fit over the wooden spokes, as it is cooled it fits perfectly over the wood
Post by: Ghost Of Highbury on May 25, 2010, 09:23:49 pm
oct nov 2007 p1 q 16,17 how???
Least thermal capacity = large temperature change. the object with least thermal capacity will be of the one with least mass - B
Heating the iron circle will expand it, and thus it will be easier to put it on the wodden circle.
Post by: Ghost Of Highbury on May 25, 2010, 09:24:41 pm
Post by: The Golden Girl =D on May 25, 2010, 09:25:50 pm
Its 2am here, im off now..night guyz. good luck.
night to u too .......pray for me ;)
Post by: Vin on May 25, 2010, 09:27:32 pm
i didnt get 16.....if temp increases it should expand and it should become larger
hold on .. look at the size of B .. By the way yes metals do expand on heating but it is jus linear expansion and they expand by VERY small length
like Aluminium expands 0.00003per *C
B is said to have the least thermal capacity = mass * specific heat capacity
as the mass is less compared to others.. thermal capacity too would be less
Post by: Vin on May 25, 2010, 09:28:40 pm
Its 2am here, im off now..night guyz. good luck.
ok dude .. bye imma solve 2 papers and sleep .. Thanks for your help today ! :D
Post by: guMnam on May 25, 2010, 09:30:26 pm
Post by: Shazizzzle on May 25, 2010, 09:41:02 pm
Post by: Ivo on May 25, 2010, 09:42:11 pm
Post by: Naruto123 on May 25, 2010, 09:56:31 pm
Post by: W.J-Knight on May 25, 2010, 10:10:05 pm
http://www.xtremepapers.net/CIE/Cambridge%20IGCSE/0625%20-%20Physics/0625_w08_qp_03.pdf
Post by: Malak on May 25, 2010, 10:12:25 pm
Post by: Vin on May 25, 2010, 10:14:33 pm
june 07 q 30 ppr 1
(http://www.antonine-education.co.uk/New_items/MDM/Control_files/image001.gif)
It has a sliding contact which is used for changing the current in a circuit
Post by: High-R on May 25, 2010, 10:14:58 pm
i got this question of the stone being thrown upwards and comes down.....and it asks where is the gravitational energy the least....so the answer is: tht the gravitationalenergy is least when the stone is just about to touch the ground!!!
can anyone explain y?...and how..wats this Gr.Energy?
Post by: 6394 on May 25, 2010, 10:16:21 pm
hey ppl wats gravitational ENERGY?lol hamz no 1 noes
i got this question of the stone being thrown upwards and comes down.....and it asks where is the gravitational energy the least....so the answer is: tht the gravitationalenergy is least when the stone is just about to touch the ground!!!
can anyone explain y?...and how..wats this Gr.Energy?
acha sun konsa ppr kr rahi hai!!!
Post by: Vin on May 25, 2010, 10:19:00 pm
How do u calculate the Circumference?
One COMPLETE revolution is the circumference ..
Post by: Syed Kazim on May 25, 2010, 10:21:17 pm
Can anyone please explain electromagnetic induction. Which cuts which?
Electromagnetic induction is the process of producing electricity from magnetism. Faraday suggested that a voltage is induced in a conductor whenever it 'cuts' magnetic field lines, i.e. moves across them. Note that a voltage is not induced if the conductor moves along them or is at rest.
The induced voltage increases with the increase of:
- the speed of motion of the magnet or coil,
- the number of turns in the coil,
- the strength of the magnet.
To answer your second question, the conductor 'cuts' the magnetic field lines.
Post by: pglasg74 on May 25, 2010, 10:22:32 pm
and how do you know which fuse to choose? like for a lamp that operates at .25 A, and the wire can carry 4 A, how do u kno tht the fuse is 1A :S:S:S
and gravitational energy is energy that an object has when its not on the ground (or any origin) so if u throw a stone from the mountain, right at the top is the most gravitational energy, and right at the bottom is the least.. proportional to height
Post by: $H00t!N& $t@r on May 25, 2010, 10:23:41 pm
Post by: Vin on May 25, 2010, 10:24:35 pm
hey ppl wats gravitational ENERGY?
i got this question of the stone being thrown upwards and comes down.....and it asks where is the gravitational energy the least....so the answer is: tht the gravitationalenergy is least when the stone is just about to touch the ground!!!
can anyone explain y?...and how..wats this Gr.Energy?
@6394 .. i know :P muhje pataa hai :P
GRAVITATIONAL POTENTIAL ENERGY is the amount of energy stored in a body at a particular height ..
FORMULA :: P.E = m*g*h
mass, acceleration due to gravity(10 m/s2), and height
eg wen u stand on a flight of stairs of 10m then ur
PE = 60kg * 10 * 10
=6000J
wen u stand at the bottom of the stairs (ground level) your PE = 60 * 10 * 0 = 0 J
so least PE is at the bottom .. ;)
Post by: pglasg74 on May 25, 2010, 10:28:45 pm
@6394 .. i know :P muhje pataa hai :P
GRAVITATIONAL POTENTIAL ENERGY is the amount of energy stored in a body at a particular height ..
FORMULA :: P.E = m*g*h
mass, acceleration due to gravity(10 m/s2), and height
eg wen u stand on a flight of stairs of 10m then ur
PE = 60kg * 10 * 10
=6000J
wen u stand at the bottom of the stairs (ground level) your PE = 60 * 10 * 0 = 0 J
can u exp the q i posted on pg 106 PLEASE? thanks :D
so least PE is at the bottom .. ;)
Post by: 6394 on May 25, 2010, 10:29:52 pm
@6394 .. i know :P muhje pataa hai :Plol mein to mazaak kar raha tha :P :P :P
GRAVITATIONAL POTENTIAL ENERGY is the amount of energy stored in a body at a particular height ..
FORMULA :: P.E = m*g*h
mass, acceleration due to gravity(10 m/s2), and height
eg wen u stand on a flight of stairs of 10m then ur
PE = 60kg * 10 * 10
=6000J
wen u stand at the bottom of the stairs (ground level) your PE = 60 * 10 * 0 = 0 J
so least PE is at the bottom .. ;)
tumhe to sab ata hai :) :)
MA
Post by: pglasg74 on May 25, 2010, 10:31:49 pm
Post by: 6394 on May 25, 2010, 10:32:02 pm
@6394 .. i know :P muhje pataa hai :Plol at the m=60
GRAVITATIONAL POTENTIAL ENERGY is the amount of energy stored in a body at a particular height ..
FORMULA :: P.E = m*g*h
mass, acceleration due to gravity(10 m/s2), and height
eg wen u stand on a flight of stairs of 10m then ur
PE = 60kg * 10 * 10
=6000J
wen u stand at the bottom of the stairs (ground level) your PE = 60 * 10 * 0 = 0 J
so least PE is at the bottom .. ;)
:DDDDDD
Post by: Malak on May 25, 2010, 10:32:18 pm
lol hamz no 1 noesLol....I understand tht.. :P
acha sun konsa ppr kr rahi hai!!!
Post by: Vin on May 25, 2010, 10:34:09 pm
can someone explain how we can reduce heat transfer by radiation, by convection and conduction please? respectively?
and how do you know which fuse to choose? like for a lamp that operates at .25 A, and the wire can carry 4 A, how do u kno tht the fuse is 1A :S:S:S
ok u can reduce heat transfer by using an insulator, shiny/light surface that reflects the heat, insulation or thick insulating materials
As far as i can comprehend
By conduction :: insulator/insulation
By convection :: (I have no idea :()
By Radiation :: shiny/light surface
You come to know which fuse to use wen u look at the OPTIONS given in the ques .. usually a fuse which is more than the appliances' given amperes and less than the amount of current the wire the wire can hold
gimme a ques frm a past paper i'll help ;)
Post by: $H00t!N& $t@r on May 25, 2010, 10:37:14 pm
@6394 aik bat puchoon tum larka ho ke larki? cz in one of ur posts u wr like "mein to mazak raha tha" but then ur profile shows ur gender as female..
Post by: Vin on May 25, 2010, 10:41:47 pm
some1 answer my question....
@6394 aik bat puchoon tum larka ho ke larki? cz in one of ur posts u wr like "mein to mazak raha tha" but then ur profile shows ur gender as female..
LMAO !! :D gimme 2 mins ;)
Post by: 6394 on May 25, 2010, 10:42:02 pm
some1 answer my question....lol no m a larki
@6394 aik bat puchoon tum larka ho ke larki? cz in one of ur posts u wr like "mein to mazak raha tha" but then ur profile shows ur gender as female..
but have this aadat of sayin .....ga ga ga
rofl :P ;D ;D ;D
Post by: pglasg74 on May 25, 2010, 10:45:19 pm
LMAO !! :D gimme 2 mins ;)
thxxx 4 ans. mine, can u answer the fuse one as well? and also, can you tell me oct/november 2006 #23 please? CAN SOMEONE TELL ME TEH RELATION BETWEEN FREQUENCY, AMPLITUDE, PITCH AND LOUDNESS PLEASEPLEASEPLEASEPLEASE?
Post by: Vin on May 25, 2010, 10:46:43 pm
vin.. ca u exp my qs on pg 106.. nd tell me oct nov 2005 # 39...
remember this ..
In a beta decay a neutron changes to a proton and an electron .. The proton remains in the nucleus and electron is emitted as a beta particle
eg . isotope of carbon .. carbon 14
146C ----> 714N + -1e
in your ques .. 145 neutrons remain the same .. 92 protons INCREASE to 93
Post by: $H00t!N& $t@r on May 25, 2010, 10:47:03 pm
lol no m a larkitomboy?
but have this aadat of sayin .....ga ga ga
rofl :P ;D ;D ;D
Post by: 6394 on May 25, 2010, 10:48:54 pm
tomboy?han yahi smajhlo
;D ;D
Post by: $H00t!N& $t@r on May 25, 2010, 10:49:44 pm
Post by: Syed Kazim on May 25, 2010, 10:50:15 pm
thxxx 4 ans. mine, can u answer the fuse one as well? and also, can you tell me oct/november 2006 #23 please? CAN SOMEONE TELL ME TEH RELATION BETWEEN FREQUENCY, AMPLITUDE, PITCH AND LOUDNESS PLEASEPLEASEPLEASEPLEASE?
When the frequency increases, the pitch of a sound increases.
When the amplitude increase, a sound becomes louder.
Post by: $H00t!N& $t@r on May 25, 2010, 10:51:00 pm
Post by: Vin on May 25, 2010, 10:51:47 pm
m/j 2005 q32. The answer is b. why?? i thought its A. nd can u explain y its nt A...vin im still waiting.... hope u hvnt forgotten me :'(
OK listen .. A is a variable resistor .. so it can be used to vary the pd/current/resistance .. BUT if u notice it is connected in parallel with the lamp .. the rule states that appliances connected in parallel receive EQUAL pd ..
B is a potentiometer(variable resistor) here it is used as a rheostat where it has a sliding contact which is used to vary the current and pd ..
Post by: mysteryman on May 25, 2010, 10:54:20 pm
and in those questions about the 4 blocks and the temperature changes are given then they ask which one has the greatest thermal capacity. what should i write?
like in: http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_1.pdf
question 16
Post by: pglasg74 on May 25, 2010, 10:55:22 pm
remember this ..
In a beta decay a neutron changes to a proton and an electron .. The proton remains in the nucleus and electron is emitted as a beta particle
eg . isotope of carbon .. carbon 14
146C ----> 714N + -1e
in your ques .. 145 neutrons remain the same .. 92 protons INCREASE to 93
that's what i thought but the answer is B not D :S:S
Post by: 6394 on May 25, 2010, 10:56:39 pm
>:( ;D ;D ;D ;D ;D
Post by: pglasg74 on May 25, 2010, 10:57:30 pm
Post by: Vin on May 25, 2010, 10:58:22 pm
thxxx 4 ans. mine, can u answer the fuse one as well? and also, can you tell me oct/november 2006 #23 please? CAN SOMEONE TELL ME TEH RELATION BETWEEN FREQUENCY, AMPLITUDE, PITCH AND LOUDNESS PLEASEPLEASEPLEASEPLEASE?
for the fuse one i have modified the post .. can u post a ques frm a past paper .. it'll be easy to explain ..
(http://www.antonine-education.co.uk/New_items/MUS/images/Making6.gif)
Amplitude is the height ..
Frequency is the number of oscillations per sec
Pitch depends upon the frequency of the wave .. high-pitched is high frequency but smaller wavelength and Low-pitch is low frequency and greater wavelength
Post by: $H00t!N& $t@r on May 25, 2010, 10:59:09 pm
ahhh i see. Thanks again! ;)
OK listen .. A is a variable resistor .. so it can be used to vary the pd/current/resistance .. BUT if u notice it is connected in parallel with the lamp .. the rule states that appliances connected in parallel receive EQUAL pd ..
B is a potentiometer(variable resistor) here it is used as a rheostat where it has a sliding contact which is used to vary the current and pd ..
Post by: mysteryman on May 25, 2010, 11:00:21 pm
Post by: Vin on May 25, 2010, 11:01:15 pm
that's what i thought but the answer is B not D :S:S
remember this ..
In a beta decay a neutron changes to a proton and an electron .. The proton remains in the nucleus and electron is emitted as a beta particle
eg . isotope of carbon .. carbon 14
146C ----> 714N + -1e
in your ques .. 145 neutrons remain the same .. 92 protons INCREASE to 93
got it ??
Post by: pglasg74 on May 25, 2010, 11:03:21 pm
Post by: Naruto123 on May 25, 2010, 11:04:59 pm
Post by: Naruto123 on May 25, 2010, 11:08:46 pm
Post by: mysteryman on May 25, 2010, 11:09:33 pm
winter 05 ques 31 ppr1 physics helpppppppp may Allah help u in return
remember that current always takes the path of least resistance
when S is open, all the current has to go through the resistor since there is no other path
but when its closed, most of the current will go towards S since it has less resistance
so more current will go through the lamp therefore increasing brightness
Post by: Vin on May 25, 2010, 11:11:54 pm
in those questions about the compass, where shouldnt the needle point?
and in those questions about the 4 blocks and the temperature changes are given then they ask which one has the greatest thermal capacity. what should i write?
like in: http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_1.pdf
question 16
in those questions about the compass, where shouldnt the needle point?
https://studentforums.biz/index.php/topic,6468.msg225169.html#msg225169
https://studentforums.biz/index.php/topic,6468.msg225177.html#msg225177
and in those questions about the 4 blocks and the temperature changes are given then they ask which one has the greatest thermal capacity. what should i write?
The one having the greatest mass has the greatest thermal capacity
Q 16)
at 0*C both are solid
at 50*C both are liquid
at 100*C and 150*C Benzene is gas
so B
Post by: Vin on May 25, 2010, 11:13:15 pm
OI THE ANSWER IS 144 AND 93, NT 145 N 93... I CHECKEDDD
yea right ... .. ... .. lemme check on google
Post by: Syed Kazim on May 25, 2010, 11:13:49 pm
winter 05 ques 31 ppr1 physics helpppppppp may Allah help u in return
Question 31 the answer is A. It becomes brighter because when the switch is closed then there is another path for the current to pass through instead of the one which has the resistor.
Question 32 the answer is C. Because the voltage in a parallel circuit is the same for all components connected in parallel across the source.
Post by: mysteryman on May 25, 2010, 11:14:07 pm
and ques 32 also plzzzz
Answer A is incorrect because the current doesnt have to be the same in every circuit
B is wrong because that is a property of a series connection where all the lamps are switched on and off together
C is correct because the voltage across each lamp has to be the same as the mains voltage
D isnt right because that is another property of a series connection where one lamp can destroy the circuit
Post by: pglasg74 on May 25, 2010, 11:15:23 pm
and ques 32 also plzzzz
ill help u wiht this one.. take your room as an example, whne u turn the light on, are aall the bulbs equally bright? yes they are, thats why..
vin ill give u the fuse qn.. here:
"A mains current can safely supply a current of 40 A. A hairdryer takes 2A. It is connected to the circuit by a lead which can safely carry up to 5 A.
Which fuse is best to use in the plug fitted to the hairdryer lead?"
1 A, 3 A, 50 A OR 10 A?
Post by: pglasg74 on May 25, 2010, 11:16:31 pm
Post by: mysteryman on May 25, 2010, 11:17:25 pm
in those questions about the compass, where shouldnt the needle point?
https://studentforums.biz/index.php/topic,6468.msg225169.html#msg225169
https://studentforums.biz/index.php/topic,6468.msg225177.html#msg225177
and in those questions about the 4 blocks and the temperature changes are given then they ask which one has the greatest thermal capacity. what should i write?
The one having the greatest mass has the greatest thermal capacity
Q 16)
at 0*C both are solid
at 50*C both are liquid
at 100*C and 150*C Benzene is gas
so B
thanks alot. one more question about the thermal capacity
can you explain why the rest are incorrect in: http://www.freeexampapers.us/IGCSE/Physics/CIE/2006%20Jun/0625_s06_qp_1.pdf question 16
the answer is A
Post by: Shazizzzle on May 25, 2010, 11:18:24 pm
Post by: Syed Kazim on May 25, 2010, 11:21:45 pm
Post by: Vin on May 25, 2010, 11:22:04 pm
thanks alot. one more question about the thermal capacity
can you explain why the rest are incorrect in: http://www.freeexampapers.us/IGCSE/Physics/CIE/2006%20Jun/0625_s06_qp_1.pdf question 16
the answer is A
look at the temperature difference .. only A has a temperature rise of 2 *C .. greatest thermal capacity
others have increased by 8, 4,6 as their thermal capacity is lesser
Post by: Syed Kazim on May 25, 2010, 11:22:39 pm
Guys, STOP! ENOUGH! :P
;D
Post by: Ivo on May 25, 2010, 11:22:53 pm
Post by: Vin on May 25, 2010, 11:23:11 pm
In Beta decay a neutron changes to a proton and an electron. The proton remains in the nucleus and the electron is emitted as a beta-particle. The new nucleus has the same nucleon number, but its proton number increases by one since it has one more proton.
hey can u explain this ??/
Post by: pglasg74 on May 25, 2010, 11:23:45 pm
In Beta decay a neutron changes to a proton and an electron. The proton remains in the nucleus and the electron is emitted as a beta-particle. The new nucleus has the same nucleon number, but its proton number increases by one since it has one more proton.
alriiiiight thanksss a lot :P khuda jo shukr ha the samjh main achi vayo..
Post by: pglasg74 on May 25, 2010, 11:25:53 pm
look at the temperature difference .. only A has a temperature rise of 2 *C .. greatest thermal capacity
others have increased by 8, 4,6 as their thermal capacity is lesser
vin can u explain.. i dont understand questions like #20 in summer 07.. like i dont get it, isnt wavelength supposed to decrease when they enter deeper, why are they further apart? why is the answer c not b :S:S:S:S
and i posted the fuse question before..
Post by: Syed Kazim on May 25, 2010, 11:27:24 pm
Please please can someone answer these questions: S06 - Qs 19 and 20.
Question 19: D.
It cannot be A because radiation is not prevented by an air gap.
It cannot be B because heat does pass through the sides of the cup.
It cannot be C because hot air rises and thus it will not go by convection to the bottom.
It has to be D.
Post by: High-R on May 25, 2010, 11:28:20 pm
lol hamz no 1 noes@6394 lol ya ...finishd all ppr..no more i think ill do
acha sun konsa ppr kr rahi hai!!!
PPL PLZ TELL ME....VIN???
Post by: Syed Kazim on May 25, 2010, 11:30:03 pm
Question 19: D.
It cannot be A because radiation is not prevented by an air gap.
It cannot be B because heat does pass through the sides of the cup.
It cannot be C because hot air rises and thus it will not go by convection to the bottom.
It has to be D.
Question 20: D.
It cannot be A because that is the definition of wave-length.
It cannot be B because that is half a wave-length.
It cannot be C because speed of a water wave is not measured by particles moving up and down rather by wave-front moving along a surface.
It has to be D.
Post by: Vin on May 25, 2010, 11:30:16 pm
vin ill give u the fuse qn.. here:
"A mains current can safely supply a current of 40 A. A hairdryer takes 2A. It is connected to the circuit by a lead which can safely carry up to 5 A.
Which fuse is best to use in the plug fitted to the hairdryer lead?"
1 A, 3 A, 50 A OR 10 A?
ok i think its 3A .. 50 A and 10 A are out of the ques because they will cause the wire to melt as it can carry only 5 A
1 A is used then the dryer will not work because it requires a minimum of 2 A
Post by: Ivo on May 25, 2010, 11:31:19 pm
vin can u explain.. i dont understand questions like #20 in summer 07.. like i dont get it, isnt wavelength supposed to decrease when they enter deeper, why are they further apart? why is the answer c not b :S:S:S:S
and i posted the fuse question before..
If you look at the question, it says from shallow to deeper water, so they travel quickly don't they, the waves when they enter the deeper water.
Must be C because, lambda=v/f so if speed increases, frequency is constant (same colour), so wavelength increases, so lines are further apart.
Got it? ;D
Post by: High-R on May 25, 2010, 11:33:11 pm
hey ppl wats gravitational ENERGY?plz reply!!!...HURRY!!!!!!!!!
i got this question of the stone being thrown upwards and comes down.....and it asks where is the gravitational energy the least....so the answer is: tht the gravitationalenergy is least when the stone is just about to touch the ground!!!
can anyone explain y?...and how..wats this Gr.Energy?
Post by: pglasg74 on May 25, 2010, 11:34:04 pm
If you look at the question, it says from shallow to deeper water, so they travel quickly don't they, the waves when they enter the deeper water.
Must be C because, lambda=v/f so if speed increases, frequency is constant (same colour), so wavelength increases, so lines are further apart.
Got it? ;D
no the answer says which diagram shows the waves in the DEEPER region..
Post by: pglasg74 on May 25, 2010, 11:34:28 pm
In Beta decay a neutron changes to a proton and an electron. The proton remains in the nucleus and the electron is emitted as a beta-particle. The new nucleus has the same nucleon number, but its proton number increases by one since it has one more proton.
thanks, now can u answer "A mains current can safely supply a current of 40 A. A hairdryer takes 2A. It is connected to the circuit by a lead which can safely carry up to 5 A.
Which fuse is best to use in the plug fitted to the hairdryer lead?"
1 A, 3 A, 50 A OR 10 A?
and pls explain how to select the best fuse..
Post by: Ivo on May 25, 2010, 11:35:27 pm
plz reply!!!...HURRY!!!!!!!!!
GPE: energy due to position.
KE: energy due to motion.
So at start, GPE is greatest (no motion). When thrown up (GPE converted to KE) then momentarily stops at top of flightpath (GPE again) then when it drops (GPE to KE increases), so just before it hits, KE is greatest, therefore a lot of GPE has been converted, therefore GPE is least. Got it? ;D
Post by: Vin on May 25, 2010, 11:35:32 pm
BEST OF LUCK TO ALL !! :D
Post by: Ivo on May 25, 2010, 11:36:13 pm
no the answer says which diagram shows the waves in the DEEPER region..
Excactly, the words in the question say they travel quickly in deeper water, so speed of waves are quicker, wavelength increases, as explained with the formula before.
Post by: pglasg74 on May 25, 2010, 11:36:57 pm
ok i think its 3A .. 50 A and 10 A are out of the ques because they will cause the wire to melt as it can carry only 5 A
1 A is used then the dryer will not work because it requires a minimum of 2 A
yeah i got that.. how about this one?
The current in a lamp at full brightness is 0.25 A. The flexible cable to the lamp is designed for currents upto 5 A so it can safely carry teh 0.25 taken by the lamp. Which fuse should be inserted in the plug at the other end of the cable?
.. teh answer is 1
Post by: Syed Kazim on May 25, 2010, 11:37:53 pm
vin can u explain.. i dont understand questions like #20 in summer 07.. like i dont get it, isnt wavelength supposed to decrease when they enter deeper, why are they further apart? why is the answer c not b :S:S:S:S
and i posted the fuse question before..
Water waves have a shorter wave-length in shallow water, i.e. they travel more slowly.
Water waves have a longer wave-length in deep water, i.e. they travel fast.
Post by: Ivo on May 25, 2010, 11:38:35 pm
thanks, now can u answer "A mains current can safely supply a current of 40 A. A hairdryer takes 2A. It is connected to the circuit by a lead which can safely carry up to 5 A.
Which fuse is best to use in the plug fitted to the hairdryer lead?"
1 A, 3 A, 50 A OR 10 A?
and pls explain how to select the best fuse..
3A, cos hairdryer only needs 2A. In general, take the max current needed by appliance, then select the fuse with rating of the next one up. So 4A, would need 5A fuse, for example. Using 13A fuse for this would be dangerous, cos of the larger current.
Post by: Syed Kazim on May 25, 2010, 11:39:42 pm
OK GUYS IMMA SLEEP NOW !! Its 4 am here !!.. n i need some sleep ..sorry guys if u r questions are pending :(
BEST OF LUCK TO ALL !! :D
Thanks for your help. :)
Post by: Ivo on May 25, 2010, 11:40:22 pm
yeah i got that.. how about this one?
The current in a lamp at full brightness is 0.25 A. The flexible cable to the lamp is designed for currents upto 5 A so it can safely carry teh 0.25 taken by the lamp. Which fuse should be inserted in the plug at the other end of the cable?
.. teh answer is 1
Yes, max. required by lamp is 0.25A, so you select fuse which is the next one up. So 1.5A, is 3A fuse, for example.
Post by: pglasg74 on May 25, 2010, 11:43:03 pm
Excactly, the words in the question say they travel quickly in deeper water, so speed of waves are quicker, wavelength increases, as explained with the formula before.
ooooo riiiiiiiiight tyyyyy :D so wavelength in shallow is less than wavelength in deep?
Post by: pglasg74 on May 25, 2010, 11:44:18 pm
Thanks for your help. :)
hey can u explain winter 07 number 21 please?
Post by: Ivo on May 25, 2010, 11:44:28 pm
ooooo riiiiiiiiight tyyyyy :D so wavelength in shallow is less than wavelength in deep?
In shallow water, waves travel slowly. Look at the formula v=f(lambda-wavelength). So rearange: wavelength=v/f.
So, if v deceases, and frequency is the same, then wavelengh decresases. Therefore the lines in the diagram get shorter for shallow water. Opposite for deep water. Got it? ;D
Post by: pglasg74 on May 25, 2010, 11:48:18 pm
In shallow water, waves travel slowly. Look at the formula v=f(lambda-wavelength). So rearange: wavelength=v/f.
So, if v deceases, and frequency is the same, then wavelengh decresases. Therefore the lines in the diagram get shorter for shallow water. Opposite for deep water. Got it? ;D
hey can u explain winter 07 number 21 please?
+ rep 4 u :)
Post by: Ivo on May 25, 2010, 11:49:18 pm
hey can u explain winter 07 number 21 please?
+ rep 4 u :)
Still water surface basically means the middle. Between the peak and trough. So B, right? Think of it this way, the oscillations are perpendicular to wave direction, with maximum reachable amplitude is to the peak and through, and so the middle is the average between the two.
Post by: pglasg74 on May 25, 2010, 11:57:42 pm
Still water surface basically means the middle. Between the peak and trough. So B, right? Think of it this way, the oscillations are perpendicular to wave direction, with maximum reachable amplitude is to the peak and through, and so the middle is the average between the two.
right, so smart lol :P, thanks 2 last questions please :)
39, winter 07... the answer's B, but didnt we always talk about decreasing resistance by increasing are (using thicker cables :S) why are we suddenly changing the concept now?
and also, for a fuse.. we always choose the rate next from the device? like if the hairdryer is 1.25 A, ill choose 2 not 3.. but if its 2.5 ill choose 3 not 4?
Post by: Ivo on May 26, 2010, 12:40:37 am
right, so smart lol :P, thanks 2 last questions please :)
39, winter 07... the answer's B, but didnt we always talk about decreasing resistance by increasing are (using thicker cables :S) why are we suddenly changing the concept now?
and also, for a fuse.. we always choose the rate next from the device? like if the hairdryer is 1.25 A, ill choose 2 not 3.. but if its 2.5 ill choose 3 not 4?
LOL, dunno q.39 isn't about it.
For fuses, yes you're correct. I'm not sure, but I think fuses generally only have ratings of 1A, 3A, 5A, and 15A; but that doesn't matter :P.
Post by: jellybeans on May 26, 2010, 02:24:39 am
some explanation neeeeded please thankyouuuu!
;D
Post by: Weaam on May 26, 2010, 04:27:40 am
HIIII!! :D :DI can helpp yoou!
some explanation neeeeded please thankyouuuu!
;D
For the first one Q21, the answer is B, its not A cuz the water can never reach that high after it settles, there are too many big spaces between the wave and the next.
Its not C, cuz when the water settles, itll be highher cuz of the peaks of the waves.
For Q36, just imagine a generator in your head, which parts are always brushing against each other? Its defentily not the coil and brushes, or the coil and the magnet, or even the magnet and the slip ring because they dont even touch! it has to be D, slip ring and brushes.
Post by: jellybeans on May 26, 2010, 04:54:08 am
I can helpp yoou!
For the first one Q21, the answer is B, its not A cuz the water can never reach that high after it settles, there are too many big spaces between the wave and the next.
Its not C, cuz when the water settles, itll be highher cuz of the peaks of the waves.
For Q36, just imagine a generator in your head, which parts are always brushing against each other? Its defentily not the coil and brushes, or the coil and the magnet, or even the magnet and the slip ring because they dont even touch! it has to be D, slip ring and brushes.
hahaha ohhh thanks! ;D got the 2nd bit. but not the first bit :P hahahaha... how dyu know that it'll be higher? and... uhm where the peaks wud be?
THANKS agaiiin :D
Post by: Weaam on May 26, 2010, 05:04:42 am
hahaha ohhh thanks! ;D got the 2nd bit. but not the first bit :P hahahaha... how dyu know that it'll be higher? and... uhm where the peaks wud be?umm... ill put it in another way, when there are waves passing, there are higher bits and lower bits, so its not C because when the water settles, the higher bits will settle too, so making the water level rise a little, get it now?
THANKS agaiiin :D
Ur welcooome! :D
Post by: holtadit on May 26, 2010, 05:07:18 am
hahaha ohhh thanks! ;D got the 2nd bit. but not the first bit :P hahahaha... how dyu know that it'll be higher? and... uhm where the peaks wud be?
THANKS agaiiin :D
This is an application of the amplitude of a transverse wave. The amplitude is the max displacement from a mean position.
Post by: Weaam on May 26, 2010, 05:17:48 am
Post by: Weaam on May 26, 2010, 05:24:14 am
Post by: Vin on May 26, 2010, 07:07:27 am
Im having trouble understanding Q13 in O/N 07, could you plz explain, i dunt get why the lvl rises but the pressure stays the same
ok i know you are off to give the exam but .. for ur knowledge
when the atmospheric pressure increases the level rises .. look for the attachment ..
Pressure at P remains the same because P is a vacuum which is nor affected by pressure ..
Post by: red_911 on May 26, 2010, 08:08:46 am
Post by: Ghost Of Highbury on May 26, 2010, 08:11:50 am
why is question 21 0625/01/M/J/06 B ? ??? ??? :-X
Speed = Frequency * Wavelength
Speed decreases, frequency is constant, thus, wavelength decreases (distance between the lines)
it doesnt refract, water waves...travels straight..
Post by: WARRIOR on May 26, 2010, 08:15:41 am
Speed = Frequency * Wavelength
Speed decreases, frequency is constant, thus, wavelength decreases (distance between the lines)
it doesnt refract, water waves...travels straight..
yestterday you told me
H= I^2 X R
what is the constant? here?
and does this forumula work for wires ..like decrease the resistance decrease heat loss?
work for transformers ..like increasign voltage decreases heat loss?
Post by: Ghost Of Highbury on May 26, 2010, 08:19:17 am
yestterday you told me
H= I^2 X R
what is the constant? here?
and does this forumula work for wires ..like decrease the resistance decrease heat loss?
work for transformers ..like increasign voltage decreases heat loss?
ok this is basically used for transmission of power in overhead cables..
P = V*I
The power is high, thus to decrease current, u have to increase the voltage(so that the power stays the same)
thus high voltage reduces current...and reduced current means reduced heat loss, or electrical energy transferred..
H = I2R
Resistant of wire constant
Post by: WARRIOR on May 26, 2010, 08:23:04 am
ok this is basically used for transmission of power in overhead cables..
P = V*I
The power is high, thus to decrease current, u have to increase the voltage(so that the power stays the same)
thus high voltage reduces current...and reduced current means reduced heat loss, or electrical energy transferred..
H = I2R
Resistant of wire constant
ooh i see cheers i get now
+ rep ;)
Post by: princess12 on May 26, 2010, 08:31:44 am
Post by: haris94 on May 26, 2010, 08:35:20 am
mine was good
wbu?
Post by: princess12 on May 26, 2010, 08:36:17 am
Post by: DANDUNAH on May 26, 2010, 08:37:07 am
thanks in advance
Post by: haris94 on May 26, 2010, 08:39:54 am
i have not registered for physics
oh i c
when is your next exam?
Post by: WARRIOR on May 26, 2010, 08:41:30 am
specific latent heat is the amount of energy needed to change state of 1kg of substance
forumal S.T.H = E/m
Energy over mass
anythin else
Post by: princess12 on May 26, 2010, 08:42:16 am
Post by: WARRIOR on May 26, 2010, 08:42:58 am
CHEMISTRY PAPER 3 ON 7 JUNE 2010
lol i suppose then u startd ur summer holidays :P
Post by: haris94 on May 26, 2010, 08:44:57 am
CHEMISTRY PAPER 3 ON 7 JUNE 2010
wow!! looooong break.......nice......enjoy it while u can ;)
Post by: Raywin on May 26, 2010, 08:48:51 am
Post by: WARRIOR on May 26, 2010, 08:51:35 am
Hmmm... physics was pretty good but need to discuss it .... :)lucky you have mornin exam !!!
i have to wait till 3:30 in the afternoon to do a 45 minut exam =.=
Post by: 8T on May 26, 2010, 08:54:39 am
Can i please get help with may june 03 paper 3 q 4 b
I know how but in the mark scheme it says 6.4 * 10 ?
Could sum1 explain..
Thanks in advance.
Post by: Raywin on May 26, 2010, 08:58:07 am
lucky you have mornin exam !!!
i have to wait till 3:30 in the afternoon to do a 45 minut exam =.=
LOL... yeah im lucky i guess.. and GOOD LUCK !! :)
Post by: holtadit on May 26, 2010, 09:02:16 am
Hello.
Can i please get help with may june 03 paper 3 q 4 b
I know how but in the mark scheme it says 6.4 * 10 ?
Could sum1 explain..
Thanks in advance.
Now solve for X and you'll get the answer
Post by: princess12 on May 26, 2010, 09:03:32 am
Post by: WARRIOR on May 26, 2010, 09:04:29 am
Can someone please explain :
Question 2 C ii
Paper is attached. :)
lol in physics doubts :P?
ok
yeast can only work in absence of OXYGEN !..because of anaerobic respiration
also oxygen should not be present to prevent ehtanol oxidation to ehtanoic acid which wil kill the yeast
Post by: 8T on May 26, 2010, 09:06:46 am
Ari, i said i know what to do therefore i did that & i got 640000 and in the ms it says 6.4 * 10
Now solve for X and you'll get the answer
Thts where i need help (:
Post by: Ghost Of Highbury on May 26, 2010, 09:08:13 am
Sorry WRONG PAPER !!!!!
Q2 C ii
2c doesnt exist
Post by: WARRIOR on May 26, 2010, 09:09:26 am
2c doesnt existit was scarred of you and ran away :P
Post by: holtadit on May 26, 2010, 09:09:56 am
Post by: haris94 on May 26, 2010, 09:10:35 am
Ari, i said i know what to do therefore i did that & i got 640000 and in the ms it says 6.4 * 10
Thts where i need help (:
the unit given in the question for pressure is Pa (N/m2)
so try changing the cm3 to m3 and see if u get it
Post by: Raywin on May 26, 2010, 09:12:08 am
Can someone please explain :
Question 2 C ii
Paper is attached. :)
Its because only when there is ANaerobic respiration (absence of o2), the result will be ethanol.
Post by: WARRIOR on May 26, 2010, 09:13:24 am
WRONG PAPER AGAIN !!! (STUPID ME)VELOCITY HAS DIRECTION !
SO AT THE BEGING THE SPEED WAS + 9m/s AND THEN IT TURNED ANOTHER DIRECTION AND GAINED SPEED ( since its in anothe rdirection it willl be -8m/s
SO WHAT IS THE DIFFRENCT
+9 - ( -8)
17 right?
Post by: Ghost Of Highbury on May 26, 2010, 09:22:09 am
WRONG PAPER AGAIN !!! (STUPID ME)
velocity is a vector quantity .. so add 9.5 m/s to 8 m/s = 17.5 m/s
9.5-(-8) = 17.5m/s
Post by: Shazizzzle on May 26, 2010, 09:27:30 am
And people here are already preparing for paper 3!
Post by: 8T on May 26, 2010, 09:27:59 am
the unit given in the question for pressure is Pa (N/m2)Oh thanks.. but i did it by 100^3 * cm^3 both numbers but i got 6.4 this time.. and repeated so no chance of error .. could u try it out and list the steps please..
so try changing the cm3 to m3 and see if u get it
The answer is 6.4 * 10 =64
Post by: 8T on May 26, 2010, 09:29:01 am
3 hours, 30 mins to our paper 1.Haha.. you'll get just as much time.
And people here are already preparing for paper 3!
Don't Worry (:
Post by: holtadit on May 26, 2010, 09:29:19 am
velocity is a vector quantity .. so add 9.5 m/s to 8 m/s = 17.5 m/s
9.5-(-8) = 17.5m/s
Thanks A@di. ;D
Post by: holtadit on May 26, 2010, 09:30:55 am
Oh thanks.. but i did it by 100^3 * cm^3 both numbers but i got 6.4 this time.. and repeated so no chance of error .. could u try it out and list the steps please..
The answer is 6.4 * 10 =64
8T in the MS they missed out the POWER number.
You see they missed out the ^5
ITS A PRINITING ERROR !!!!
Your asnwer is correct. ;)
Post by: haris94 on May 26, 2010, 09:32:43 am
8T in the MS they missed out the POWER number.
You see they missed out the ^5
ITS A PRINITING ERROR !!!!
Your asnwer is correct. ;)
ya prolly
i also got 6.4*10^5 Pa
Post by: haris94 on May 26, 2010, 09:34:14 am
Oh thanks.. but i did it by 100^3 * cm^3 both numbers but i got 6.4 this time.. and repeated so no chance of error .. could u try it out and list the steps please..
The answer is 6.4 * 10 =64
u should get 6.4*10^5 with converting to m3 and without converting
ms must be wrong
Post by: 8T on May 26, 2010, 09:34:27 am
8T in the MS they missed out the POWER number.Lol Ari , I thought so too..
You see they missed out the ^5
ITS A PRINITING ERROR !!!!
Your asnwer is correct. ;)
But when u change to m^3 as required you would get 6.4 not 6.4 * 10 .
Now that cannot be a typing error my friend am I correct?
Post by: Girlie45 on May 26, 2010, 09:35:23 am
I thought B-particles only change the proton number :S
Post by: Ghost Of Highbury on May 26, 2010, 09:36:51 am
Hey guys in O/N 05 ,paper 1, question 39 why is the answer B ? ???
I thought B-particles only change the proton number :S
a neutron spilts into a proton and an electron, the electron is emitted.
so no. of neutrons decreases by 1, and no. of protons increases by 1.
Post by: CatAly$t on May 26, 2010, 09:37:19 am
what is the real answer...m confused now....ms said 64.... ??? ??? :-\
Post by: SoONa on May 26, 2010, 09:39:34 am
How many of the following changes could happen to the ball because of the force?
• a change in direction
• a change in shape
• a change in mass
• a change in speed
A 1 B 2 C 3 D 4
the answer is C which is 3 but i didnt understand why??
Post by: Weaam on May 26, 2010, 09:39:55 am
ok i know you are off to give the exam but .. for ur knowledge
when the atmospheric pressure increases the level rises .. look for the attachment ..
Pressure at P remains the same because P is a vacuum which is nor affected by pressure ..
Im done with the exam but thanks anyway ;)
Post by: haris94 on May 26, 2010, 09:40:50 am
me too i was solving p3 2003 and got 6.4*10^5
what is the real answer...m confused now....ms said 64.... ??? ??? :-\
it has to be 6.4*10^5 Pa
Post by: Shazizzzle on May 26, 2010, 09:43:02 am
A force acts on a moving rubber ball.
How many of the following changes could happen to the ball because of the force?
• a change in direction
• a change in shape
• a change in mass
• a change in speed
A 1 B 2 C 3 D 4
the answer is C which is 3 but i didnt understand why??
3, because, A force CAN change the direction, shape, and speed, BUT a force CANNOT change the mass of an object.
Recall forces.
So...
Only 3/4 are correct, thus C.
Post by: SoONa on May 26, 2010, 09:43:56 am
3, because, A force CAN change the direction, shape, and speed, BUT a force CANNOT change the mass of an object.
Recall forces.
So...
Only 3/4 are correct, thus C.
Thanks A million ;D
Post by: Girlie45 on May 26, 2010, 09:46:45 am
a neutron spilts into a proton and an electron, the electron is emitted.
so no. of neutrons decreases by 1, and no. of protons increases by 1.
Thanx! By the way liking the stewie pic ;D hahaha
Post by: Dana on May 26, 2010, 09:48:04 am
http://www.freeexampapers.us/IGCSE/Physics/CIE/1993%20Nov/0625_w93_qp_01.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/1993%20Nov/0625_w93_qp_01.pdf)
It says which diagram shows the diffraction of a wave going through a wide gap.
Isn't it C? The one that shows the waves slightly bent at the ends, and not D as the mark scheme says, which shows perfectly curved waves?? ???
Post by: Ghost Of Highbury on May 26, 2010, 09:48:37 am
Thanx! By the way liking the stewie pic ;D hahaha
STEWIE GRIFFIN FTW!!!!
Post by: Ghost Of Highbury on May 26, 2010, 09:50:37 am
In Nov 93 number 19
http://www.freeexampapers.us/IGCSE/Physics/CIE/1993%20Nov/0625_w93_qp_01.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/1993%20Nov/0625_w93_qp_01.pdf)
It says which diagram shows the diffraction of a wave going through a wide gap.
Isn't it C? The one that shows the waves slightly bent at the ends, and not D as the mark scheme says, which shows perfectly curved waves?? ???
Should be C. Incorrect MS?
Post by: haris94 on May 26, 2010, 09:51:27 am
In Nov 93 number 19
http://www.freeexampapers.us/IGCSE/Physics/CIE/1993%20Nov/0625_w93_qp_01.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/1993%20Nov/0625_w93_qp_01.pdf)
It says which diagram shows the diffraction of a wave going through a wide gap.
Isn't it C? The one that shows the waves slightly bent at the ends, and not D as the mark scheme says, which shows perfectly curved waves?? ???
i think its C
the gap is wide
Post by: Dana on May 26, 2010, 09:51:48 am
Should be C. Incorrect MS?I dno :/ how can I tell?
Post by: 8T on May 26, 2010, 09:52:20 am
u should get 6.4*10^5 with converting to m3 and without convertingSo can u do the conversion and show me please because i keep getting 6.4 ??
ms must be wrong
In both with and without???
Thanks
Post by: Ivo on May 26, 2010, 09:53:04 am
Should be C. Incorrect MS?
I agree. The gap is wider than the wavelength, so yeah totally agree it's C. It's not the proper mark scheme anyway.
Post by: Dana on May 26, 2010, 09:54:16 am
I agree. The gap is wider than the wavelength, so yeah totally agree it's C. It's not the proper mark scheme anyway.Okay thanks :D
but wait if the gap wasn't wider than the wavelength, it'd be D? :S
Post by: Ghost Of Highbury on May 26, 2010, 09:55:28 am
Okay thanks :D
but wait if the gap wasn't wider than the wavelength, it'd be D? :S
D, yes.
Post by: Dana on May 26, 2010, 09:56:38 am
D, yes.Learn a new thing everyday, thanks!
Do you think the exam's gonna be tough? Cuz chem yesterday was super easy
Post by: Ghost Of Highbury on May 26, 2010, 09:58:05 am
Learn a new thing everyday, thanks!
Do you think the exam's gonna be tough? Cuz chem yesterday was super easy
No Clue. CIE is evil.
Post by: Ivo on May 26, 2010, 09:58:22 am
Learn a new thing everyday, thanks!
Do you think the exam's gonna be tough? Cuz chem yesterday was super easy
I'll say, Phy P1 will be harder than Chem P1, but then P3 would be easier than Bio! :D
Post by: haris94 on May 26, 2010, 09:59:21 am
So can u do the conversion and show me please because i keep getting 6.4 ??
In both with and without???
Thanks
without conversion:
p= (2*10^5)*80
25
u should get 640000 Pa
with conversion:
p= (2*10^5)*(8*10^-5) 1 m3 = 1000000 cm3
(2.5*10^-5)
u should get 640000 Pa
Post by: SoONa on May 26, 2010, 09:59:47 am
circuit in 30 minutes.
What is the average speed of the car?
A 75 km / hour
B 90 km / hour
C 150 km / hour
D 750 km / hour
2. A sample of a solid is heated for 12 minutes and its temperature noted every minute.
The results are shown in the table.
time / min 0 1 2 3 4 5 6 7 8 9 10 11 12
temperature / °C 11.5 16.1 22.1 31.0 31.1 31.1 31.1 31.3 45.0 65.2 66.2 66.3 66.3
How should the sample be described at the end of the 12 minutes?
A all solid
B in the process of melting
C all liquid
D in the process of boiling
thanks in advance
Post by: Ivo on May 26, 2010, 10:00:00 am
Post by: The Golden Girl =D on May 26, 2010, 10:00:31 am
By the way, just wanted to know whether solving past papers for 1993-2000 is worth it for P1, or should I do all of 2003 onwards first.
2000 and onwards ;)
Post by: Weaam on May 26, 2010, 10:00:46 am
So can u do the conversion and show me please because i keep getting 6.4 ??
In both with and without???
Thanks
Tuleen?
Post by: Girlie45 on May 26, 2010, 10:01:26 am
No Clue. CIE is evil.
LOL agreed.
Post by: Ivo on May 26, 2010, 10:02:03 am
1.The circuit of a motor racing track is 3 km in length. In a race, a car goes 25 times round the
circuit in 30 minutes.
What is the average speed of the car?
A 75 km / hour
B 90 km / hour
C 150 km / hour
D 750 km / hour
2. A sample of a solid is heated for 12 minutes and its temperature noted every minute.
The results are shown in the table.
time / min 0 1 2 3 4 5 6 7 8 9 10 11 12
temperature / °C 11.5 16.1 22.1 31.0 31.1 31.1 31.1 31.3 45.0 65.2 66.2 66.3 66.3
How should the sample be described at the end of the 12 minutes?
A all solid
B in the process of melting
C all liquid
D in the process of boiling
thanks in advance
Answer is 150 km/h, because 150/0.5 is that.
Post by: Dana on May 26, 2010, 10:02:18 am
By the way, just wanted to know whether solving past papers for 1993-2000 is worth it for P1, or should I do all of 2003 onwards first.I think you should do older ones, there was a qs that came in chem yesterday from may 2000. Copy paste. I think CIE thinks we'll like forget abt the older ones so they get more questions from previous years :P also take a look at gce
Post by: Dana on May 26, 2010, 10:03:26 am
I'll say, Phy P1 will be harder than Chem P1, but then P3 would be easier than Bio! :DHahaha :P Bio was the WORST exam ever! >:( I hated it! And I'm pretty worried abt chem and physics p3 :/
Post by: Ivo on May 26, 2010, 10:03:37 am
1.The circuit of a motor racing track is 3 km in length. In a race, a car goes 25 times round the
circuit in 30 minutes.
What is the average speed of the car?
A 75 km / hour
B 90 km / hour
C 150 km / hour
D 750 km / hour
2. A sample of a solid is heated for 12 minutes and its temperature noted every minute.
The results are shown in the table.
time / min 0 1 2 3 4 5 6 7 8 9 10 11 12
temperature / °C 11.5 16.1 22.1 31.0 31.1 31.1 31.1 31.3 45.0 65.2 66.2 66.3 66.3
How should the sample be described at the end of the 12 minutes?
A all solid
B in the process of melting
C all liquid
D in the process of boiling
thanks in advance
D, I reckon for the second one. Cos of latent heat for 2nd time, no change in temp for boiling or melting.
Post by: Ivo on May 26, 2010, 10:04:21 am
Hahaha :P Bio was the WORST exam ever! >:( I hated it! And I'm pretty worried abt chem and physics p3 :/
Chem P3, I wouldn't be worried about that, we've got half-term to revise.
Phy P3, I'm worried! :D
Bio P3, worst in 10 years, says it all!
Post by: SoONa on May 26, 2010, 10:06:28 am
Post by: Ghost Of Highbury on May 26, 2010, 10:06:47 am
D, I reckon for the second one. Cos of latent heat for 2nd time, no change in temp for boiling or melting.
in the process of boiling??
Post by: Ivo on May 26, 2010, 10:07:56 am
in the process of boiling??
Yeah, that's what I'm thinking, cos melting is 31 degree bit.
Post by: Dana on May 26, 2010, 10:08:15 am
Chem P3, I wouldn't be worried about that, we've got half-term to revise.Yea at least we've got abt 10 days to revise for chem :)
Phy P3, I'm worried! :D
Bio P3, worst in 10 years, says it all!
was your bio exam all about ecology and then like one thing abt reproduction? or did you have another variant that had absolutely nothing abt humans?
Post by: haris94 on May 26, 2010, 10:08:53 am
cause temperature is constant while the state of matter is changing cause of latent heat
Post by: Ivo on May 26, 2010, 10:09:06 am
Yup ur write for both thank u but 4 the 1st 1 wht did u do 2 get 150 i didnt get it maybee my nerves r getting 2 meee
3 * 25, because 1 lap is 3km, so 25 laps, is ......? Answer's 150km in case you didn't get it :D
Post by: 8T on May 26, 2010, 10:09:56 am
Tuleen?Hah, Yeah :D
Hi Wewe :P
Answer me if u can|?
Post by: Ghost Of Highbury on May 26, 2010, 10:10:16 am
Yeah, that's what I'm thinking, cos melting is 31 degree bit.
Temperature constant when in the process of changing state. Solid to liquid has been done, liquid to gas takes place..
Post by: Ivo on May 26, 2010, 10:10:21 am
should be.....yea
cause temperature is constant while the state of matter is changing cause of latent heat
During melting or boiling, the heat energy supplied is used to break bonds in liquid, therefore no temperature increase. Apparantly latent heat of vaporisation is defined as: the energy supplied to change a liquid into a gas without a change in temperature.
Post by: Raywin on May 26, 2010, 10:11:35 am
Post by: Weaam on May 26, 2010, 10:14:18 am
Hah, Yeah :D
Hi Wewe :P
Answer me if u can|?
Answer what? Your name is retarded. hahaha xD
Ma t5afee ma r7 27kee la7ada ;)
Post by: haris94 on May 26, 2010, 10:15:57 am
During melting or boiling, the heat energy supplied is used to break bonds in liquid, therefore no temperature increase. Apparantly latent heat of vaporisation is defined as: the energy supplied to change a liquid into a gas without a change in temperature.
precisely :)
Post by: 8T on May 26, 2010, 10:19:20 am
Answer what? Your name is retarded. hahaha xDLol mish laha ldaraji :P
Ma t5afee ma r7 27kee la7ada ;)
U already spelled my name .. wtvr
Anyway umm trace it bak may june 03 q 3 b P1V1=P2V2
Do we convert cm^3 to m^3 since Pa (N/m^2)??
Post by: Shazizzzle on May 26, 2010, 10:19:49 am
First of all, aren't beta particles electrons? Why, then are they emitted from the NUCLEUS, as states Q38 of M/J 2008, P1? :S ???
Secondly, O/N 2005, Q36, P1, I know you said that a neutron splits to form an electron and proton, but why can't we use the simple beta emission formula here. The -1B particle, where A remains A, and Z + 1? :S Isn't that formula for unstable nuclei too? Because, a stable one doesn't emit anything.
Post by: Ivo on May 26, 2010, 10:22:25 am
Two things.
First of all, aren't beta particles electrons? Why, then are they emitted from the NUCLEUS, as states Q38 of M/J 2008, P1? :S ???
Secondly, O/N 2005, Q36, P1, I know you said that a neutron splits to form an electron and proton, but why can't we use the simple beta emission formula here. The -1B particle, where A remains A, and Z + 1? :S Isn't that formula for unstable nuclei too? Because, a stable one doesn't emit anything.
For your first question, it is simple. If there are radioactive (unstable) nuclei, then it decays to becoming more stable. However, during the process of decay, a beta particle is emitted from the nucleus. And yes, beta particles are electrons.
Post by: Weaam on May 26, 2010, 10:24:13 am
Lol mish laha ldaraji :POh yeaaah, sorry abt that :P
U already spelled my name .. wtvr
Anyway umm trace it bak may june 03 q 3 b P1V1=P2V2
Do we convert cm^3 to m^3 since Pa (N/m^2)??
Post by: Vin on May 26, 2010, 10:25:33 am
For your first question, it is simple. If there are radioactive (unstable) nuclei, then it decays to becoming more stable. However, during the process of decay, a beta particle is emitted from the nucleus. And yes, beta particles are electrons.
what about positrons ?? they are beta decay too right ??
Post by: Ghost Of Highbury on May 26, 2010, 10:25:48 am
Two things.
First of all, aren't beta particles electrons? Why, then are they emitted from the NUCLEUS, as states Q38 of M/J 2008, P1? :S ???
Secondly, O/N 2005, Q36, P1, I know you said that a neutron splits to form an electron and proton, but why can't we use the simple beta emission formula here. The -1B particle, where A remains A, and Z + 1? :S Isn't that formula for unstable nuclei too? Because, a stable one doesn't emit anything.
In beta decay, the weak interaction converts a neutron (n) into a proton (p) while emitting an electron (e-)
First) 38)m/j06. As the above states, the electron comes from the neutron, the neutron is in the nucleus.
Second) When a beta particle is emitted, The mass remains the same, because a neturon is replaced by a proton, the no. of neutrons decrease , no. of proton increases.
Post by: Ivo on May 26, 2010, 10:25:54 am
Two things.
First of all, aren't beta particles electrons? Why, then are they emitted from the NUCLEUS, as states Q38 of M/J 2008, P1? :S ???
Secondly, O/N 2005, Q36, P1, I know you said that a neutron splits to form an electron and proton, but why can't we use the simple beta emission formula here. The -1B particle, where A remains A, and Z + 1? :S Isn't that formula for unstable nuclei too? Because, a stable one doesn't emit anything.
145 0 145
A -> beta + Z
92 -1 93
Answer is D, oui ou non?
Post by: 6394 on May 26, 2010, 10:26:33 am
induction opp poles are formed like attachmnt!! :P :P
n strkin same poles r formd ryt!!!!!!
??????????
Post by: Shazizzzle on May 26, 2010, 10:27:30 am
145 0 145
A -> beta + Z
92 -1 93
Answer is D, oui ou non?
Non, They say answer is B!
And I get it now. See A@di's post.
Post by: Ivo on May 26, 2010, 10:28:27 am
k jus wanna mak sure abt somthing
induction opp poles are formed like attachmnt!! :P :P
n strkin same poles r formd ryt!!!!!!
??????????
I think induction always causes attraction.
Post by: Shazizzzle on May 26, 2010, 10:28:45 am
In beta decay, the weak interaction converts a neutron (n) into a proton (p) while emitting an electron (e-)
First) 38)m/j06. As the above states, the electron comes from the neutron, the neutron is in the nucleus.
Second) When a beta particle is emitted, The mass remains the same, because a neturon is replaced by a proton, the no. of neutrons decrease , no. of proton increases.
OH! Okay! Thanks! :)
I Can't believe we weren't told this!
+rep :)
Post by: Dana on May 26, 2010, 10:29:25 am
Hey guys... slip ring commutators split rings and brushes.. :S wht r they and wht r they present in? Thxs in advance.. :)Slip rings are in generators they remove the current produced. the brushes hold them in place i think and are attached to the coils/wires where the voltmeter/ammeters are. Look in your book I'm sure there's a drawing there for a genrator.
Split ring commutators are in motors and are there to ensure that the motor continues to spin.
Hope I helped!
Post by: Ghost Of Highbury on May 26, 2010, 10:31:07 am
OH! Okay! Thanks! :)Anytime.
I Can't believe we weren't told this!
+rep :)
Post by: Dana on May 26, 2010, 10:31:43 am
The specific heat capacity of copper is 400 J / (kg K).
What is the rise in temperature?
A 5K
B 10K
C 20K
D 50K
Help? :(
Post by: Ivo on May 26, 2010, 10:31:47 am
145 0 145
A -> beta + Z
92 -1 93
Answer is D, oui ou non?
So is this now right?
237 0 237
A -> beta + Z
92 -1 93
So is it B then because 237-93 is 144, which is no of neutrons. And protons is 93? Can we think of it this way?
Post by: Vin on May 26, 2010, 10:32:25 am
145 0 145
A -> beta + Z
92 -1 93
Answer is D, oui ou non?
Je suis desole, ce n'est pas la reponse ! Even i thought the same way ! But turned out to be B
Post by: Ivo on May 26, 2010, 10:34:25 am
A 2 kg mass of copper is heated for 40 s by a heater that produces 100 J / s.
The specific heat capacity of copper is 400 J / (kg K).
What is the rise in temperature?
A 5K
B 10K
C 20K
D 50K
Help? :(
P=E/T so E=PT=100*40=4,000
E=mCT so T=E/mc = 4000/(2*400) = 5
A?
Post by: Raywin on May 26, 2010, 10:34:35 am
Slip rings are in generators they remove the current produced. the brushes hold them in place i think and are attached to the coils/wires where the voltmeter/ammeters are. Look in your book I'm sure there's a drawing there for a genrator.
Split ring commutators are in motors and are there to ensure that the motor continues to spin.
Hope I helped!
:D Yep u did!! :D Thanks a lot!
Post by: Vin on May 26, 2010, 10:35:05 am
So is this now right?
237 0 237
A -> beta + Z
92 -1 93
So is it B then because 237-93 is 144, which is no of neutrons. And protons is 93? Can we think of it this way?
yes i think so .. :D
Post by: holtadit on May 26, 2010, 10:36:44 am
Post by: WARRIOR on May 26, 2010, 10:38:36 am
what does 200m tell her about the radio wave?
freq
wave leng
sped
ampl
Post by: Shazizzzle on May 26, 2010, 10:38:59 am
What are logic gates made from ???
Silicon, or germanium.
Post by: Ivo on May 26, 2010, 10:39:33 am
a women tune her radio to a station broadcasting on 200m
what does 200m tell her about the radio wave?
freq
wave leng
sped
ampl
My guess is wavelength, but am not sure!
Post by: holtadit on May 26, 2010, 10:39:57 am
Silicon, or germanium.
What components are logic gates made from ?
Post by: Vin on May 26, 2010, 10:40:25 am
What are logic gates made from ???
I think they are made from different combination of transistors- semiconductors and stuff .. it would be different for each gate.. :-\
Post by: Vin on May 26, 2010, 10:41:12 am
My guess is wavelength, but am not sure!
yup it has to be right ??
Post by: Ivo on May 26, 2010, 10:41:16 am
What components are logic gates made from ?
Transistors right?
Post by: the_grim_reaper on May 26, 2010, 10:43:03 am
Post by: 8T on May 26, 2010, 10:44:07 am
yup it has to be right ??I think its frequency
Post by: the_grim_reaper on May 26, 2010, 10:45:12 am
My guess is wavelength, but am not sure!
Has to be wavelength. Frequency and speed aren't measured in metres and I've never heard radios brodcasting waves with an amplitude of 200 metres :D.
Post by: Dana on May 26, 2010, 10:45:46 am
P=E/T so E=PT=100*40=4,000Ohhh I totally ignored the 40s. Thanks so much :D
E=mCT so T=E/mc = 4000/(2*400) = 5
A?
Post by: holtadit on May 26, 2010, 10:46:17 am
Transistors and semi-conductors no doubt. But since they are made from germanium or silicon, so logic gates can be made up of em'. Don't worry, they won't ask you to make one in paper 1 ;D ;D...
I FINISHED PAPER 1
I am studying for PAPER 3
Post by: Ghost Of Highbury on May 26, 2010, 10:46:57 am
What components are logic gates made from ?
http://www.play-hookey.com/digital/electronics/
dont worry, they wont ask wat is inside a logic gate..
Post by: 6394 on May 26, 2010, 10:50:12 am
http://www.play-hookey.com/digital/electronics/no dey do i dnt rem i thnk in mocks or sumthin
dont worry, they wont ask wat is inside a logic gate..
ddey asked wat components are logic gates made from ?
one is transistor n othr i will chk my txt bk
Post by: WARRIOR on May 26, 2010, 10:51:28 am
http://www.play-hookey.com/digital/electronics/aadi for u
dont worry, they wont ask wat is inside a logic gate..
a women tune her radio to a station broadcasting on 200m
what does 200m tell her about the radio wave?
freq
wave leng
sped
ampl
Post by: Dana on May 26, 2010, 10:51:37 am
Four metal rods are placed, in turn, inside a coil of copper wire.
Which rod would be the most suitable to use for the core of a coil in a circuit breaker?
number of paper clips picked up when there is a current in the coil: number of paper clips still attracted when the current is switched off:
A 1 0
B 20 2
C 35 0
D 35 30
Post by: Ivo on May 26, 2010, 10:51:42 am
However, a magent has poles. To make magnet, you place in d.c. current.
I'm not sure, but am i right in saying that in magnetic induction, the thing being induced is not a magnet, because it does not have magnetic field lines?
By the way, iron is magnetically soft, so loses magnetism easily right?
Post by: Ivo on May 26, 2010, 10:52:55 am
What abt this one ::) I really don't get it? ???
Four metal rods are placed, in turn, inside a coil of copper wire.
Which rod would be the most suitable to use for the core of a coil in a circuit breaker?
number of paper clips picked up when there is a current in the coil: number of paper clips still attracted when the current is switched off:
A 1 0
B 20 2
C 35 0
D 35 30
C, right. Cos you want a electromagnet which magnetisises and demagnetises easily. Electromagnets lose magentism when current is siwtiched off, that's why it's zero when off.
Post by: 6394 on May 26, 2010, 10:53:37 am
because m done ??!11??!!
Post by: dodi23 on May 26, 2010, 10:54:38 am
Post by: Ghost Of Highbury on May 26, 2010, 10:54:59 am
aadi for u
a women tune her radio to a station broadcasting on 200m
what does 200m tell her about the radio wave?
freq
wave leng
sped
ampl
if m is meter, shud be wavelength. although, the wavelength of medium wave radio is 100 m...anyway...
Post by: Dana on May 26, 2010, 10:56:09 am
C, right. Cos you want a electromagnet which magnetisises and demagnetises easily. Electromagnets lose magentism when current is siwtiched off, that's why it's zero when off.That's what I was thinking.. I'll check and tell you. Thanks alot!
Post by: Dana on May 26, 2010, 10:56:43 am
@ kimo jesus n dana wen r u ppl gettin ovr wid phy ppr 1My exam's in about 2 hours
because m done ??!11??!!
how was it???
Post by: Weaam on May 26, 2010, 10:56:58 am
And how to demagnetise it?
Thank You! ;D
Post by: WARRIOR on May 26, 2010, 10:57:14 am
What abt this one ::) I really don't get it? ???its C
Four metal rods are placed, in turn, inside a coil of copper wire.
Which rod would be the most suitable to use for the core of a coil in a circuit breaker?
number of paper clips picked up when there is a current in the coil: number of paper clips still attracted when the current is switched off:
A 1 0
B 20 2
C 35 0
D 35 30
why? caz elctro magnets should be magnetic whn the current is switched off !
and which attraacts more A or C ..whn current is on? C
im doin the exam in 2 hours an haa half
Post by: Ivo on May 26, 2010, 10:57:31 am
Can anyone tell me how to magnetise steel?
And how to demagnetise it?
Thank You! ;D
https://studentforums.biz/index.php/topic,7946.msg210346.html#msg210346
Post by: the_grim_reaper on May 26, 2010, 10:57:45 am
@ kimo jesus n dana wen r u ppl gettin ovr wid phy ppr 1
because m done ??!11??!!
Don't worry Lad. It's still 12:55 PM in KSA and my paper is at 3 PM. So there's still A LOT of time left for everyone to get rid of paper 1 :D :D.
(Don't worry I don't want to know if it was hard or easy or whatever. If I fail, I'll fail on my own. It I pass, I'll pass on my own. Way of the Samurai :D :D :D)....
Post by: Ivo on May 26, 2010, 10:58:17 am
Can anyone please clear doubt about magnetism. So ferrous materials can be magnetised (e.g. iron and steel). All ferrous materials can be magnetically induced (so both sides of a magnetic object attracts).
However, a magent has poles. To make magnet, you place in d.c. current.
I'm not sure, but am i right in saying that in magnetic induction, the thing being induced is not a magnet, because it does not have magnetic field lines?
By the way, iron is magnetically soft, so loses magnetism easily right?
Please can someone answer my qu. thanks a lot!
Post by: Dana on May 26, 2010, 10:58:38 am
its CThanks :)
why? caz elctro magnets should be magnetic whn the current is switched off !
and which attraacts more A or C ..whn current is on? C
im doin the exam in 2 hours an haa half
Post by: Dana on May 26, 2010, 10:59:51 am
Don't worry Lad. It's still 12:55 PM in KSA and my paper is at 3 PM. So there's still A LOT of time left for everyone to get rid of paper 1 :D :D.Noooo I wanna know if it was easy or difficult! So i can brace myself uno? :P
(Don't worry I don't want to know if it was hard or easy or whatever. If I fail, I'll fail on my own. It I pass, I'll pass on my own. Way of the Samurai :D :D :D)....
I'm doing it in Saudi too! Which city are you in?
Post by: holtadit on May 26, 2010, 11:00:27 am
See below.
Post by: Vin on May 26, 2010, 11:01:57 am
How ???
See below.
you can place it in a known Temperature .. to calibrate
Post by: WARRIOR on May 26, 2010, 11:04:57 am
Thanks :)
oooooooooooops wrong explanation !!!!!!
look elcectro magnets are made of iron...temporary magnets...so when elecrtromagnet is switched off..iron stops workin and it looses it magnetism!!!!!!
get my point?
Post by: Ghost Of Highbury on May 26, 2010, 11:06:30 am
How ???
See below.
Boiling water, Melting Ice. Mark 0 degree and 100 degree Celsius. draw equal divisions..
Post by: Dana on May 26, 2010, 11:07:28 am
oooooooooooops wrong explanation !!!!!!hahaha yes I got that a loong time ago xD isn' that what you said the first time? I couldn't really get it cuz of the slang sorry :P ::)
look elcectro magnets are made of iron...temporary magnets...so when elecrtromagnet is switched off..iron stops workin and it looses it magnetism!!!!!!
get my point?
Post by: Weaam on May 26, 2010, 11:07:52 am
https://studentforums.biz/index.php/topic,7946.msg210346.html#msg210346
Thanks! or rather, i have to be thanking Kimo
Post by: ~HyDrOgEn~ on May 26, 2010, 11:13:06 am
May/June 2005, paper 1 , Question 27, what is that!!
Post by: OBADATH on May 26, 2010, 11:14:47 am
please help..exam in two hours
Post by: Ghost Of Highbury on May 26, 2010, 11:17:01 am
Yo, anyone can help me with this question:
May/June 2005, paper 1 , Question 27, what is that!!
A - both point towards north
Post by: Ivo on May 26, 2010, 11:18:16 am
Can anyone please clear doubt about magnetism. So ferrous materials can be magnetised (e.g. iron and steel). All ferrous materials can be magnetically induced (so both sides of a magnetic object attracts).
However, a magent has poles. To make magnet, you place in d.c. current.
I'm not sure, but am i right in saying that in magnetic induction, the thing being induced is not a magnet, because it does not have magnetic field lines?
By the way, iron is magnetically soft, so loses magnetism easily right?
Please please can someone clarify thins, thanks!
Post by: the_grim_reaper on May 26, 2010, 11:20:34 am
Noooo I wanna know if it was easy or difficult! So i can brace myself uno? :P
I'm doing it in Saudi too! Which city are you in?
The great city of Riyadh lol. With Minarat-ar-Riyadh as my centre and an invigilator who scares the heck out of me evrytime I see him. You should never try to know how easy or hard a paper was. If it was easy, you'll get over-confident. If it was hard, you'll already be freaked out and u'll screw you're grade. Besides, it's a different varient too so it's useless to find out if the other varient was easy or hard...
Post by: Ghost Of Highbury on May 26, 2010, 11:21:03 am
Please please can someone clarify thins, thanks!
yes, because it doesnt hav magnetic field.
Post by: Dana on May 26, 2010, 11:22:22 am
Please please can someone clarify thins, thanks!I didn't really understand everything you said but yes to magnetise a material you wound a coil over it and pass a d.c. through the coil. And yes iron is magnetically soft thus loses magnetism easily and is used as the core of an electromagnet.
Umm what else? Ferrous substances are the ones that have alot of Iron.. I dno if ALL of them can be magnetised though
hope I helped
Post by: Ivo on May 26, 2010, 11:24:32 am
I didn't really understand everything you said but yes to magnetise a material you wound a coil over it and pass a d.c. through the coil. And yes iron is magnetically soft thus loses magnetism easily and is used as the core of an electromagnet.
Umm what else? Ferrous substances are the ones that have alot of Iron.. I dno if ALL of them can be magnetised though
hope I helped
So what's the difference between magentic induction and magnetising magnet then? Like passing through dc and stuff
Post by: Dana on May 26, 2010, 11:24:54 am
The great city of Riyadh lol. With Minarat-ar-Riyadh as my centre and an invigilator who scares the heck out of me evrytime I see him. You should never try to know how easy or hard a paper was. If it was easy, you'll get over-confident. If it was hard, you'll already be freaked out and u'll screw you're grade. Besides, it's a different varient too so it's useless to find out if the other varient was easy or hard...Ahh yes I used to live in Riyadh now I live in Khobar. How is it there?
Haha we have a pretty > >:( invigilator too. Gives the dirtiest looks you'll ever see -.- Almost got kicked out of my bio exam cuz i forgot my statement of entry ::)
Yeaa I guess, but usually variants are pretty similar in paper 1. I dno I still love to know whether it was easy or difficult
where ru from?
Post by: Ghost Of Highbury on May 26, 2010, 11:26:12 am
So what's the difference between magentic induction and magnetising magnet then? Like passing through dc and stuff
magnetising magnet.........??? huh?? didnt get u
Post by: Dana on May 26, 2010, 11:27:01 am
So what's the difference between magentic induction and magnetising magnet then? Like passing through dc and stuffMagnetic induction is when you magnetise a metal by bringing another magnet close to it but not touching I think. And when you take it away it's not a magnet anymore. Magnetising is more permanent I guess. And can be done by electricity, hammering etc
Post by: Ivo on May 26, 2010, 11:29:20 am
magnetising magnet.........??? huh?? didnt get u
Like can a permanent magenet be created with iron
Post by: ~HyDrOgEn~ on May 26, 2010, 11:30:24 am
A - both point towards northYeah i knowthat, but why explain!!!
Post by: Ghost Of Highbury on May 26, 2010, 11:31:15 am
Yeah i knowthat, but why explain!!!
a compass always points towards the north, the brass rod doesnt make a difference.
Post by: Ghost Of Highbury on May 26, 2010, 11:32:15 am
Like can a permanent magenet be created with iron
no iron is a soft magnetic material. it loses its magnetism easily.
steel can be used to create permanent magnets.
Post by: Ivo on May 26, 2010, 11:34:59 am
no iron is a soft magnetic material. it loses its magnetism easily.
steel can be used to create permanent magnets.
So I still don't get it. For induced magnetism, can a hard magnetic material (eg steel) be magnetised when a manget is brought near it? Does it lose magentism when magnet is taken away?
Post by: Fastal on May 26, 2010, 11:35:43 am
Post by: holtadit on May 26, 2010, 11:36:42 am
Is monochromatic light of ONE FREQUENCY or ONE WAVELENGTH ?
Post by: Dana on May 26, 2010, 11:37:54 am
Quick question.one colour thus one wavelength i guess
Is monochromatic light of ONE FREQUENCY or ONE WAVELENGTH ?
Post by: Dana on May 26, 2010, 11:38:54 am
So I still don't get it. For induced magnetism, can a hard magnetic material (eg steel) be magnetised when a manget is brought near it? Does it lose magentism when magnet is taken away?Hmm, not sure. Don't stress yourself over it too much though, I'm sure it's not THAT important. You know the basics and stuff right?
Post by: omair on May 26, 2010, 11:40:35 am
Quick question.
Is monochromatic light of ONE FREQUENCY or ONE WAVELENGTH ?
[/quoteONE WAVELENGTH
Post by: dodi23 on May 26, 2010, 11:40:57 am
Quick question.monochromatic is one colour with one definite frequency!!
Is monochromatic light of ONE FREQUENCY or ONE WAVELENGTH ?
Post by: Ghost Of Highbury on May 26, 2010, 11:41:18 am
As the speed of light is constant, and the frequency of that monochromatic light cant change, its wavelength remains the same. Provided the light is travelling in one medium.
Post by: Dana on May 26, 2010, 11:42:04 am
what are the ways of creating a magnet? can a permanent magnet be made just by magnetizing steel once with an electromagnet?magnetising with an electromagnet? ??? You mean by a coil/d.c.? Then yes, it can make a permanent magnet. You can also suspend it in the N-S position and hammer it. That'll make a permanent magnet too
Post by: the_grim_reaper on May 26, 2010, 11:43:01 am
Ahh yes I used to live in Riyadh now I live in Khobar. How is it there?
Haha we have a pretty > >:( invigilator too. Gives the dirtiest looks you'll ever see -.- Almost got kicked out of my bio exam cuz i forgot my statement of entry ::)
Yeaa I guess, but usually variants are pretty similar in paper 1. I dno I still love to know whether it was easy or difficult
where ru from?
Believe me the two variants are different as hell this time. Well some of my esteemed fellows took the liberty to call all the way to Pakistan and find out about the other variant and they were utterly disappointed after doing their papers ;D. From Pakistan but was born in Riyadh :D..
Anyway, people about to go for the exam. Any final piece of advice??? Well I've got to say something. DON'T ever forget to use the toilet before an exam. I was later to find out the consequences during my English Paper 4... :D.
Post by: Ghost Of Highbury on May 26, 2010, 11:43:12 am
Hmm, not sure. Don't stress yourself over it too much though, I'm sure it's not THAT important. You know the basics and stuff right?
Making a magnet
Stroking method (repetitive contact b/w magnet and steel)
Electrical method
Destroying magnetism
Hammering
Heating
Alternating current method
Post by: pglasg74 on May 26, 2010, 11:43:33 am
NUMBER 8 A THAAANKS AND PHYSICS PAPER 1 WAS AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAMAZING LOTSA TRICKS THO
Post by: Vin on May 26, 2010, 11:45:03 am
Quick question.
Is monochromatic light of ONE FREQUENCY or ONE WAVELENGTH ?
its the frequency of the light that determines the colour rather than wavelength because the wavelength changes in different mediums
Post by: Dana on May 26, 2010, 11:49:18 am
Believe me the two variants are different as hell this time. Well some of my esteemed fellows took the liberty to call all the way to Pakistan and find out about the other variant and they were utterly disappointed after doing their papers ;D. From Pakistan but was born in Riyadh :D..Hahahahahahahaaha xD okay! :P Good luck :P :D
Anyway, people about to go for the exam. Any final piece of advice??? Well I've got to say something. DON'T ever forget to use the toilet before an exam. I was later to find out the consequences during my English Paper 4... :D.
Post by: pglasg74 on May 26, 2010, 11:56:58 am
Post by: pglasg74 on May 26, 2010, 11:58:26 am
Hahahahahahahaaha xD okay! :P Good luck :P :D
dana do u kno noor momani?
Post by: Dana on May 26, 2010, 12:01:06 pm
can someone answer http://www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Jun/0625_s08_qp_3.pdfAhhh I hope ours is just as good! Congrats By the way :)
NUMBER 8 A THAAANKS AND PHYSICS PAPER 1 WAS AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAMAZING LOTSA TRICKS THO
for a you draw them all in parallel and you put a switch near the battery. then 3 others on each line where the lamps are.
for b) P=IV so I= P/V so 100/200 is 0.5 A. I might be wrong though check and tell me
for b)ii) I(current)= Q(charge in coulombs)/t(time in secs) 1 min=60 secs.
Q=I x t so 0.5A x 60 is 30C
for c)i) you add the total power of the first 3 lamps minus the total power of the second three lamps
ii) you take the value that you got for for the reduction in power (c)i)) over 360 secs (1x60x60)
Check the correct answer and tell me whether my answers are even remotely correct :P
Post by: Dana on May 26, 2010, 12:01:53 pm
noor momani no but i know reema and lynn momani. why?
dana do u kno noor momani?
Post by: Dana on May 26, 2010, 12:03:34 pm
you guys can someone tell me the diff (in terms of brightness) between series connections and parallel? i kno its a stupid one but tyy :Din parallel all lamps glow at the same brightness, in series they share the brightness.
Post by: 8T on May 26, 2010, 12:10:23 pm
Ahhh I hope ours is just as good! Congrats By the way :)Dana, would you please post a diagram of the drawing for me.. i dnt quite get how we illustrate it ??
for a you draw them all in parallel and you put a switch near the battery. then 3 others on each line where the lamps are.
for b) P=IV so I= P/V so 100/200 is 0.5 A. I might be wrong though check and tell me
for b)ii) I(current)= Q(charge in coulombs)/t(time in secs) 1 min=60 secs.
Q=I x t so 0.5A x 60 is 30C
for c)i) you add the total power of the first 3 lamps minus the total power of the second three lamps
ii) you take the value that you got for for the reduction in power (c)i)) over 360 secs (1x60x60)
Check the correct answer and tell me whether my answers are even remotely correct :P
Post by: 8T on May 26, 2010, 12:13:43 pm
M/J 03 7 c i) Paper 3
Post by: MasterMath on May 26, 2010, 12:23:46 pm
Post by: lmfao on May 26, 2010, 12:25:14 pm
Post by: MasterMath on May 26, 2010, 12:25:40 pm
I have issues with diagram questions so there goes another one..I guess this is what you wanted , i didnt look at the question i just read dana's explanation
M/J 03 7 c i) Paper 3
Correct me if im wrong
Post by: lmfao on May 26, 2010, 12:28:07 pm
Post by: Vin on May 26, 2010, 12:31:34 pm
hey guys got a question.may june 03 p3 q6.please help fast
Post by: lmfao on May 26, 2010, 12:31:56 pm
Post by: Vin on May 26, 2010, 12:33:02 pm
anyone!!!!!!!
DUDE CHECK THE PREVIOUS POST !! HAVE PATIENCE ITS TAKES TIME !! ;) :)
Post by: lmfao on May 26, 2010, 12:33:52 pm
Post by: holtadit on May 26, 2010, 12:35:48 pm
Post by: lmfao on May 26, 2010, 12:36:50 pm
Post by: 8T on May 26, 2010, 12:38:36 pm
Thanks 4 the effort Master (:
Post by: lmfao on May 26, 2010, 12:39:22 pm
Post by: Vin on May 26, 2010, 12:40:00 pm
I have issues with diagram questions so there goes another one..
M/J 03 7 c i) Paper 3
Post by: holtadit on May 26, 2010, 12:40:41 pm
why do transformers work only in ac
A constantly changing mag field is needed for induction to occur :)
Post by: lmfao on May 26, 2010, 12:41:47 pm
Post by: 8T on May 26, 2010, 12:43:00 pm
I need the other one Number 8a www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Jun/0625_s08_qp_3.pdf
Post by: 8Z on May 26, 2010, 12:46:30 pm
1. Transistors
2. Specific heat capacity/specific latent heat ...
Thanks in advance :)
Post by: Vin on May 26, 2010, 12:47:44 pm
ok but am really confused
ok what u do is place your protractor on the wavefront in air mark and draw 90* do the same for wavefront in the glass ..
then on the edge of the glass mark and draw 90* you'll get the Normal
y draw normal later .. because u get the specific position of both the incident and the refracted ray at that point and you HAVE to hav the normal on the point
is rays can be ANYWHERE as long as they are 90* pr perpendicular to the wavefront ;)
Post by: lmfao on May 26, 2010, 12:48:32 pm
Post by: holtadit on May 26, 2010, 12:49:14 pm
Oh thanks Vin..
I need the other one Number 8a www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Jun/0625_s08_qp_3.pdf
I'll do it, :)
HANG ON !!!
Post by: 8Z on May 26, 2010, 12:50:53 pm
When calculating the gradient of a line in PAPER 6 a mark is given for drawing a triangle 'more than half the length of the line'.
The examiners report also refers to the TRIANGLE METHOD alot. What is this method/how does it work.
The only way I know to calc. a gradient is using (y2-y1)/(x2-x1).
you get your straight line by plotting the points
then draw a triangle such that the line is the hypotenuse of a right angled triangle (if that makes sense?)
the triangle should be big so i recommend that you use the first and last point
basically it's rise over run which gives you the same answer ans (y2-y1)/(x2-x1)
Hope this helps :)
h
Post by: holtadit on May 26, 2010, 12:55:39 pm
Post by: Vin on May 26, 2010, 12:55:58 pm
Can you explain how PE and KE of water molecules change when evaporation occurs ?
Latent heat of Vaporization
If the molecules are to overcome the forces holidaying them together and gain "freedom" they need a large amount of energy. They receive this latent heat while heating which increases the PE of the molecules and NOT KE this causes only the temp rise. same for fusion
Post by: 8T on May 26, 2010, 12:56:39 pm
Check ur inbox Hun (:
you get your straight line by plotting the points
then draw a triangle such that the line is the hypotenuse of a right angled triangle (if that makes sense?)
the triangle should be big so i recommend that you use the first and last point
basically it's rise over run which gives you the same answer ans (y2-y1)/(x2-x1)
Hope this helps :)
h
Post by: Vin on May 26, 2010, 12:57:53 pm
kkl but what are the values
YOU gotta measure them .. i dont have them on hard copy and its impossible to measure them on pc ;) refer the ms
Post by: pglasg74 on May 26, 2010, 12:59:28 pm
noor momani no but i know reema and lynn momani. why?
lynn is reema's mommm?
Post by: lmfao on May 26, 2010, 12:59:57 pm
Post by: 8T on May 26, 2010, 01:00:30 pm
May 03 p3 q10 a ii)
Anyone offering help?
Post by: holtadit on May 26, 2010, 01:01:59 pm
Oh thanks Vin..
I need the other one Number 8a www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Jun/0625_s08_qp_3.pdf
Did you see my answer ?
Post by: Vin on May 26, 2010, 01:04:17 pm
Diagram:
May 03 p3 q10 a ii)
Anyone offering help?
Post by: Vin on May 26, 2010, 01:05:28 pm
Did you see my answer ?
hmmm .. nice .. could have been neater :P lol thanks ;)
Post by: mdwael on May 26, 2010, 01:05:39 pm
Post by: lmfao on May 26, 2010, 01:07:22 pm
Post by: 8T on May 26, 2010, 01:07:52 pm
Did you see my answer ?YES, Its wonderful..altho i think u labelled the wrong lamps isnt the 2 6o not 100 and 60 ??
Thanks 4 the effort !
Post by: 8T on May 26, 2010, 01:09:18 pm
Yes Vin it says that in the mark scheme but why for Q does it point to the left could you explain ..??
Post by: Vin on May 26, 2010, 01:12:16 pm
not giving
what answer r u getting ?? n which angle r u measuring ?? nothings given in the ms means the examiner will check according to what u hav done
Post by: lmfao on May 26, 2010, 01:17:09 pm
Post by: MasterMath on May 26, 2010, 01:18:29 pm
Can you explain how PE and KE of water molecules change when evaporation occurs ?When your adding heat for the water to evaporate .. First of all it happens at a constant temperature .. and we all know that Average K.E isProportional to Temp .. so K.E does not increase while evaporation is taking place because the temperature is constant .. but what happens to the heat we are adding? The heat we are adding is to provide G.P.E to the molecules so they can overcome the forces of attraction between the molecules of the liquid and thus leave the surface of water and then end up having much more G.P.E in the gas state.
Hope this helps!
Post by: Vin on May 26, 2010, 01:18:38 pm
Yes Vin it says that in the mark scheme but why for Q does it point to the left could you explain ..??
ok .. remember ALWAYS a compass North (compass point) points in the SAME direction as the direction of current .. This is Oersted's Discovery
Post by: 8T on May 26, 2010, 01:21:53 pm
ok .. remember ALWAYS a compass North (compass point) points in the SAME direction as the direction of current .. This is Oersted's DiscoveryOOOOOH!
I knew that it just slipped..
Many thanks Bud (:
Post by: The Golden Girl =D on May 26, 2010, 01:29:48 pm
Post by: Raywin on May 26, 2010, 01:33:08 pm
june 2003 ....Q10 part bi
(i) By increasing the current, the magnetic field lines is ONLY stronger. It does not change direction. It is the SAME.
(ii) By reversing the direction of current, the magnetic field reverses and so the compass points in the OPPOSITE direction.
:D
Post by: holtadit on May 26, 2010, 01:34:51 pm
You know that diagram for Lenz's Law in all textbooks ? It shows a magnet entering a solenoid....
okay, How do I predict which way the Galvananometer or ammeter will defelct ? Like will go tot the right or left and why ?
Like in the diagram below :
Which way does the ammeter pointer deflect towards ? Left or right ?
Post by: jellybeans on May 26, 2010, 01:39:56 pm
help pleaseee :D
... helllllppp .. dont really know what the MS's talking about... :(
Post by: Raywin on May 26, 2010, 01:40:19 pm
This question has been bugging me. I saw it in a few GCE past papers.
You know that diagram for Lenz's Law in all textbooks ? It shows a magnet entering a solenoid....
okay, How do I predict which way the Galvananometer or ammeter will defelct ? Like will go tot the right or left and why ?
Like in the diagram below :
Which way does the ammeter pointer deflect towards ? Left or right ?
I THINK when the magnet is first put into the solenoid, the ammeter moves to the right. Then when the magnet is pulled out, the ammeter moves to the left? Im not really sure as to WHY it does this but positive it moves in this manner
Post by: Vin on May 26, 2010, 01:41:00 pm
while removing the meter should deflect to the left because according to Lenz's law wen the mag. is removed the solenoid becomes South and attracts the mag.
Post by: ambitious94 on May 26, 2010, 01:42:19 pm
This question has been bugging me. I saw it in a few GCE past papers.Ok, for this first u have to determine the North and South poles of the solenoid. That u have to determine by Lenz's law. Now North always has anticlockwise current right? So u simply draw the arrow for the direction of current. The Ammeter needle will deflect in the direction of the current. Simple. :) like in the case of ur diagram, it will move towards the right side, cuz htat's where the current is goin
You know that diagram for Lenz's Law in all textbooks ? It shows a magnet entering a solenoid....
okay, How do I predict which way the Galvananometer or ammeter will defelct ? Like will go tot the right or left and why ?
Like in the diagram below :
Which way does the ammeter pointer deflect towards ? Left or right ?
Post by: Fastal on May 26, 2010, 01:43:48 pm
Ok, for this first u have to determine the North and South poles of the solenoid. That u have to determine by Lenz's law. Now North always has anticlockwise current right? So u simply draw the arrow for the direction of current. The Ammeter needle will deflect in the direction of the current. Simple. :) like in the case of ur diagram, it will move towards the right side, cuz htat's where the current is goin
i THINK he/she is right
Post by: Raywin on May 26, 2010, 01:44:56 pm
HI!!!! need some help here... are my answers right..? or wrong.. hehhs, :P
help pleaseee :D
... helllllppp .. dont really know what the MS's talking about... :(
I think ur right.. :P wht does the MS tell?
Post by: ambitious94 on May 26, 2010, 01:46:16 pm
Here....Thanks for this! i was just about to request the answer to it :) But one thing's bugging me. Why'd they give us the diagram of the house? Aren't those switches that are drawn in the diagram in the question...I'm gettin confused with that :)
Post by: Vin on May 26, 2010, 01:47:23 pm
Ok, for this first u have to determine the North and South poles of the solenoid. That u have to determine by Lenz's law. Now North always has anticlockwise current right? So u simply draw the arrow for the direction of current. The Ammeter needle will deflect in the direction of the current. Simple. :) like in the case of ur diagram, it will move towards the right side, cuz htat's where the current is goin
i get it
but the needle of the meter moves the opposite side too when the magnet is removed .. so can u explain that too ??
Post by: jellybeans on May 26, 2010, 01:48:05 pm
I think ur right.. :P wht does the MS tell?
for the first one, C is marked 'vertically'(?) under/at any peak & R is marked on next to trough ... but i dont get if it cud be "on" the trough. :/
for the spectrum thing, "refraction and dispersion at first face, refraction and dispersion at second face"
Post by: holtadit on May 26, 2010, 01:49:17 pm
Thanks for this! i was just about to request the answer to it :) But one thing's bugging me. Why'd they give us the diagram of the house? Aren't those switches that are drawn in the diagram in the question...I'm gettin confused with that :)
Those are DOORS
Post by: Fastal on May 26, 2010, 01:50:33 pm
i get it
but the needle of the meter moves the opposite side too when the magnet is removed .. so can u explain that too ??
the needle moves the opposite side because the induced current reverses, since now the left side of that coil has become the north pole to attract the south pole being put in.(remember lenz law)
Post by: Raywin on May 26, 2010, 01:52:08 pm
for the first one, C is marked 'vertically'(?) under/at any peak & R is marked on next to trough ... but i dont get if it cud be "on" the trough. :/
for the spectrum thing, "refraction and dispersion at first face, refraction and dispersion at second face"
Im clueless.. :S but i think ur right.. :)
Post by: holtadit on May 26, 2010, 01:54:39 pm
Please explain with a diagram how to predict which way the current flows with Lenz Law
:'( :'( :'(
Post by: ambitious94 on May 26, 2010, 01:55:14 pm
Those are DOORSLMAOOOOOOOOOOO
Post by: jellybeans on May 26, 2010, 01:56:56 pm
Im clueless.. :S but i think ur right.. :)
hahaha okay. thanks :)
Post by: jellybeans on May 26, 2010, 01:57:27 pm
Post by: holtadit on May 26, 2010, 01:57:52 pm
WHAT HAPPENS TO THE WAVELENGTH AS IT TRAVELS TO A LESS DENSE MEDIUM? D: D:
Increases
Post by: jellybeans on May 26, 2010, 01:58:42 pm
Increases
lololol. okay THANKS!
Post by: Moonlyte on May 26, 2010, 01:58:50 pm
Post by: holtadit on May 26, 2010, 02:00:24 pm
erm...how exactly do you attach images?
When posting click on additional options ;)
Post by: ambitious94 on May 26, 2010, 02:00:49 pm
I DONT GET LENZ's LAW !!!!!Lenz's law states that:direction of induced current always opposes the motion that produces it.
Please explain with a diagram how to predict which way the current flows with Lenz Law
:'( :'( :'(
When we bring a magnet towards a solenoid with the North Pole towards the solenoid's side, the solenoid tries to repel the magnet, by making the end closest to the magnet NORTH too.
Now, when the magnet is drawn away (N side still towards solenoid), the solenoid tries to ATTRACT the magnet by making it's end SOUTH, therefore current reverses.
Summary: When you bring the magnet TOWARDS the solenoid, it tries to repel. When you pull the magnet AWAY from the solenoid it tries to ATTRACT.
How does it do that? By changing it's poles!
AAH...I KNOW SUMTHING...YAY!
Post by: Fastal on May 26, 2010, 02:01:32 pm
I use the Right hand grip rule for the direction of current, except reverse.
Lenz's law-The direction of the induced current is such as to oppose the change causing it so in Diagram the coil will be induced with a North pole at the top to OPPOSE the magnet being put inside. Now use the Right Hand Grip rule and the current will go in the direction indicated.Note:the magnet is moving into the coil in the diagram.
same way when you move the magnet out of the coil it tries to attract it thus inducing the current the OTHER way
Post by: Moonlyte on May 26, 2010, 02:02:32 pm
When posting click on additional options ;)
thanks!
Post by: holtadit on May 26, 2010, 02:04:02 pm
Post by: Fastal on May 26, 2010, 02:04:55 pm
Please help me with Lenz Law. I dont understand it :'( :'(
reply #1904 :)
Post by: The Golden Girl =D on May 26, 2010, 02:06:02 pm
when the ray enters denser medium does it move AWAY or TOWARDS the normal line
ohh
and when the ray enters deep to shallow , does it move TOWARDS or AWAY
??? ??? ??? :-\ :-\
Post by: Vin on May 26, 2010, 02:07:05 pm
I DONT GET LENZ's LAW !!!!!
Please explain with a diagram how to predict which way the current flows with Lenz Law
:'( :'( :'(Please help me with Lenz Law. I dont understand it :'( :'(
http://www.youtube.com/watch?v=kU6NSh7hr7Q&feature=related
DUDE CHECK THIS ONE OUT ..IM TELLIN' YA !!
Post by: Raywin on May 26, 2010, 02:07:29 pm
Please help me with Lenz Law. I dont understand it :'( :'(
Check this website out. It has a good animation. http://www.launc.tased.edu.au/online/sciences/physics/Lenz's.html It might help.
Post by: ambitious94 on May 26, 2010, 02:08:50 pm
Please help me with Lenz Law. I dont understand it :'( :'(OH MAN..what did i right that whole story for on Page 127 >.< :P
Post by: Moonlyte on May 26, 2010, 02:12:09 pm
Post by: anonymous7 on May 26, 2010, 02:16:43 pm
5. Atomic Physics
b) Characteristics of the three kids of emission
-describe their [alpha, beta and gamma particles] deflection in electric fields and magnetic fields.
Questions based on this is pretty popular as I have seen them in numerous papers. But I don't have any notes on them and my textbook is no help what so ever. Can anyone shed some light on it?
Post by: Weaam on May 26, 2010, 02:18:33 pm
Post by: holtadit on May 26, 2010, 02:19:00 pm
The syllabus says:
5. Atomic Physics
b) Characteristics of the three kids of emission
-describe their [alpha, beta and gamma particles] deflection in electric fields and magnetic fields.
Questions based on this is pretty popular as I have seen them in numerous papers. But I don't have any notes on them and my textbook is no help what so ever. Can anyone shed some light on it?
Go here:
http://thenightdreamer.wordpress.com/2010/01/23/rutherford-scattering/
http://thenightdreamer.wordpress.com/2010/01/23/radioactive-decay/
PS : The website is mine. :) Vote or subscribe !!!
Post by: tunnellord on May 26, 2010, 02:19:54 pm
Quote
By the way i always get mixed up in this :
when the ray enters denser medium does it move AWAY or TOWARDS the normal line
ohh
and when the ray enters deep to shallow , does it move TOWARDS or AWAY
When a ray enters a denser medium, it moves towards the normal.
What do u mean by entering deep to shallow.
do u mean entering shallow from deep or shallow to deep.
Post by: Raywin on May 26, 2010, 02:20:33 pm
Can anyone help me understand Q5 part a (iii) M/J 0. I thought silver is a better emitter of heat and black is a better absorber, but it says opposite in the mark scheme :-\
Black is a better absorber. BUT good absorbers are GOOD EMITTERS. Silver doesnt emit. It reflects.
Post by: Moonlyte on May 26, 2010, 02:23:55 pm
The syllabus says:
5. Atomic Physics
b) Characteristics of the three kids of emission
-describe their [alpha, beta and gamma particles] deflection in electric fields and magnetic fields.
Questions based on this is pretty popular as I have seen them in numerous papers. But I don't have any notes on them and my textbook is no help what so ever. Can anyone shed some light on it?
Magnetic Field
If a very narrow beam of radiation from a sample of radium is given out in the presence of a magnetic field in a cloud chamber, the rays will leave 3 different tracks of cloud: gamma rays keep going straight, but alpha and beta radiations curve in opposite directions.
Electric Field
Being charged particles, alpha and beta can be deflected in an electric field, but gamma rays cannot. Alpha moves towards negative plate and beta moves toward positive plate.
Post by: Vin on May 26, 2010, 02:24:24 pm
By the way i always get mixed up in this :
when the ray enters denser medium does it move AWAY or TOWARDS the normal line
ohh
and when the ray enters deep to shallow , does it move TOWARDS or AWAY
??? ??? ??? :-\ :-\
are you confusing yourself with mechanical waves and light rays ??
Post by: Weaam on May 26, 2010, 02:26:05 pm
Is my diagram correct for Jun 2007 No. 8?
Not really, u ddnt use a variable resistor symbol, and ur switch is in the wrong place. I tried to correct it for you.
Post by: tunnellord on May 26, 2010, 02:28:16 pm
Quote
Is my diagram correct for Jun 2007 No. 8?
Yes ur diagram is actually wrong.
The ammeter is in the correct position, however the resistor has to be variable and the switch must be joined to the main wires from C and D. What i mean is that you will need to connect both C and D to the switch and connect that switch to the main circuit. :) ^-^
Post by: Moonlyte on May 26, 2010, 02:29:28 pm
Not really, u ddnt use a variable resistor symbol, and ur switch is in the wrong place. I tried to correct it for you.
oh i see...thanks a lot!
Post by: tunnellord on May 26, 2010, 02:30:01 pm
u need to connect wires to both C and D and then to the switch
Post by: Vin on May 26, 2010, 02:30:09 pm
Is my diagram correct for Jun 2007 No. 8?
which paper is this .. u think its a little incorrect ;) i;ll draw it show it to u .. tell me the paper .. ;)
i see its already done ;)
Post by: Weaam on May 26, 2010, 02:31:19 pm
Black is a better absorber. BUT good absorbers are GOOD EMITTERS. Silver doesnt emit. It reflects.Thanks so much! ;D
Post by: NightHawkerr on May 26, 2010, 02:31:50 pm
Post by: Weaam on May 26, 2010, 02:32:33 pm
weeam,Oh yeah, right.
u need to connect wires to both C and D and then to the switch
Post by: Weaam on May 26, 2010, 02:34:05 pm
oh i see...thanks a lot!Wait, the other one was a bit wrong, this is better ;D
Post by: Moonlyte on May 26, 2010, 02:34:49 pm
What's a calliper? and a vernier scale?
Vernier calipers are a type of measuring device used to measure precise increments between two points. Vernier calipers work best when used between parallel points, their intended design. Due to their precision they can be used across less stable points of reference to a high degree of accuracy. Calipers come in various sizes, but the most common is 6 inches. These tools are not intended to measure large spans.
Post by: Weaam on May 26, 2010, 02:36:10 pm
What's a calliper? and a vernier scale?They are devices used to measure very small distances, a few millimeters or less.
Post by: Moonlyte on May 26, 2010, 02:37:02 pm
Wait, the other one was a bit wrong, this is better ;D
it looks good! Thank a lot :D
Post by: jellybeans on May 26, 2010, 02:37:17 pm
Post by: Weaam on May 26, 2010, 02:38:04 pm
it looks good! Thank a lot :DYour welcoome, anytime! ;D
Post by: Moonlyte on May 26, 2010, 02:40:18 pm
HI, help? :D
Direction of current (into the page)
Post by: Vin on May 26, 2010, 02:40:46 pm
HI, help? :D
what is the direction of the current .. should be mentioned in the ques i)
Post by: jellybeans on May 26, 2010, 02:41:36 pm
Direction of current (into the page)
heyy i meant the direction of the movement , not current.. as it's already stated in the question :/
Post by: jellybeans on May 26, 2010, 02:41:59 pm
what is the direction of the current .. should be mentioned in the ques i)
OOPS SORRY. the current's "into the page"
Post by: Moonlyte on May 26, 2010, 02:44:27 pm
heyy i meant the direction of the movement , not current.. as it's already stated in the question :/
oops sorry my mistake in reading ^^
Post by: Vin on May 26, 2010, 02:44:41 pm
OOPS SORRY. the current's "into the page"
yup thts right ..
Post by: tunnellord on May 26, 2010, 02:45:42 pm
Quote
HI, help?Yes which direction is the wire. is it coming out of the page or goin into the page??
Post by: Vin on May 26, 2010, 02:46:33 pm
Yes which direction is the wire. is it coming out of the page or goin into the page??
umm .. direction of "current"
"into the page" nvm its right ;)
Post by: Hasnainali on May 26, 2010, 02:48:54 pm
Post by: Weaam on May 26, 2010, 02:49:38 pm
I dont know how this even relates to physics ...? :-\
Post by: Hasnainali on May 26, 2010, 02:50:20 pm
Post by: Malak on May 26, 2010, 02:50:21 pm
Q2: part a can u explain..?
Q6 (diagram)
Q8 part e ii and iii ...
And this is wat i drew for Q10 answer is it right?and also wats the answer for b ii?
thx
Post by: holtadit on May 26, 2010, 02:51:21 pm
Can anyone tell me the difference between analouge and digital?
I dont know how this even relates to physics ...? :-\
Analogue = continously increasing or decreasing.
Digital = increase in steps of 0.01
Post by: jellybeans on May 26, 2010, 02:51:41 pm
umm .. direction of "current"
"into the page" nvm its right ;)
sooo.. my diagram's right? :D i mean the direction of the 'movement' ... cuz if you use the left hand rule, it's point towards you, right? D;
Post by: Hasnainali on May 26, 2010, 02:53:05 pm
plz explain q8
Post by: Raywin on May 26, 2010, 02:53:14 pm
Post by: Vin on May 26, 2010, 02:54:25 pm
plz explain o level phy 5054 s09 p1 q8
post it here .. this is IGCSE board
https://studentforums.biz/index.php/board,13.0.html
Post by: holtadit on May 26, 2010, 02:54:40 pm
Hey guys is Resonance and wave interference in our syllabus...? :S
NOPE !!!!
Post by: tunnellord on May 26, 2010, 02:55:17 pm
Quote
sooo.. my diagram's right? i mean the direction of the 'movement' ... cuz if you use the left hand rule, it's point towards you, right? D;
Yes u r correct ^-^
Post by: Raywin on May 26, 2010, 02:55:39 pm
NOPE !!!!
Ryte.. :) Thx! ;D
Post by: Moonlyte on May 26, 2010, 02:58:58 pm
Post by: Weaam on May 26, 2010, 02:59:17 pm
Analogue = continously increasing or decreasing.Thanks but in the mark scheme it says digital increases or decreases by one unit.
Digital = increase in steps of 0.01
Post by: holtadit on May 26, 2010, 03:01:35 pm
Does anyone have any general tips for the exam 'cause i'm finding the past papers pretty hard!
Show all the formulas you use.
Show ALL workings (you can still get marks for wrong answers)
Be CALM and READ the question.
When writing long answers; GET TO THE POINT !!! BE CONCISE !!!!!
Post by: jellybeans on May 26, 2010, 03:01:45 pm
Yes u r correct ^-^
thhhhankyo :)
Post by: Weaam on May 26, 2010, 03:02:04 pm
Help..?
Post by: 8T on May 26, 2010, 03:02:33 pm
Could anyone check o/n 03 p3 q 2 b I keep getting 12750 but MS gives 5250
Is it wrong.. why do i keep getting stuck wityh wrong MSs??!
Post by: Malak on May 26, 2010, 03:03:26 pm
http://www.freeexampapers.us/IGCSE/Physics/CIE/2007%20Nov/0625_w07_qp_3.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2007%20Nov/0625_w07_qp_3.pdf)
Q2: part a can u explain..?
Q6 (diagram)
Q8 part e ii and iii ...
And this is wat i drew for Q10 answer is it right?and also wats the answer for b ii?
thx
Anyone??
Post by: tunnellord on May 26, 2010, 03:03:59 pm
Quote
And this is wat i drew for Q10 answer is it right?and also wats the answer for b ii?
thx
Hey angl, u can only use one NOT gate. So ur diagram is incorrect. You should connect the NOT to the electrical sensor and the AND is correct
Post by: Weaam on May 26, 2010, 03:04:15 pm
Hi again.Tully why do you solve really old pp?!
Could anyone check o/n 03 p3 q 2 b I keep getting 12750 but MS gives 5250
Is it wrong.. why do i keep getting stuck wityh wrong MSs??!
kaif 3endek wa2et t7elee mn 03 to 09? :S
Post by: holtadit on May 26, 2010, 03:05:51 pm
There is this question in m/j 04 Q11 b, it says 'wat does the scattering of alpha particles show about the atomic structure'?
Help..?
http://thenightdreamer.wordpress.com/2010/01/23/rutherford-scattering/
See my website above
Post by: 8T on May 26, 2010, 03:07:00 pm
Tully why do you solve really old pp?!SHUSH 2ENTI!!
kaif 3endek wa2et t7elee mn 03 to 09? :S
Dude u were doing 2000 ..haha..plus ur doing 04 now its just a year be4 tht so not so old..and i wont have time .. ive only don't 1 paper so far and stuck in the second ..LOOOL!
Post by: nid404 on May 26, 2010, 03:08:14 pm
There is this question in m/j 04 Q11 b, it says 'wat does the scattering of alpha particles show about the atomic structure'?
Help..?
- Most of the atom is empty space
-The mass of the atom is concentrated in the central core of the atom called nucleus
-The nucleus has an overall positive charge
Post by: Baladya on May 26, 2010, 03:09:22 pm
Harder than Chemistery but still very easy :P
Post by: Moonlyte on May 26, 2010, 03:10:23 pm
Show all the formulas you use.
Show ALL workings (you can still get marks for wrong answers)
Be CALM and READ the question.
When writing long answers; GET TO THE POINT !!! BE CONCISE !!!!!
thanks!!
Post by: Weaam on May 26, 2010, 03:11:14 pm
SHUSH 2ENTI!!i WAS NOT doing 2000s, i dunt even have them! hahaha
Dude u were doing 2000 ..haha..plus ur doing 04 now its just a year be4 tht so not so old..and i wont have time .. ive only don't 1 paper so far and stuck in the second ..LOOOL!
Entee u LOVE to ask questions so akeed r7 t3al2ee 3a every question! lool
Post by: Weaam on May 26, 2010, 03:12:52 pm
- Most of the atom is empty spaceThank yoou! ;D
-The mass of the atom is concentrated in the central core of the atom called nucleus
-The nucleus has an overall positive charge
and ill check the website too Ari!
Post by: holtadit on May 26, 2010, 03:13:06 pm
i WAS NOT doing 2000s, i dunt even have them! hahaha
Entee u LOVE to ask questions so akeed r7 t3al2ee 3a every question! lool
Lesh ?
Post by: Malak on May 26, 2010, 03:14:39 pm
Hey angl, u can only use one NOT gate. So ur diagram is incorrect. You should connect the NOT to the electrical sensor and the AND is correctOkay and thn wat about the humidity sensor..?leave it like that?
n thx
Post by: ambitious94 on May 26, 2010, 03:15:12 pm
I dunno how to prepare to phy, I've done overall almost all papers from 2002 onwards. Should I read the theory or repeat the papers (since I didnt do them all today, did them in 3 or 4 months). A lil advice wud b appreciated!
Post by: Ghost Of Highbury on May 26, 2010, 03:16:00 pm
Anyone??
2a) Much of the energy islost to overcome friction resisting its motion.
6)attached
Post by: tunnellord on May 26, 2010, 03:16:05 pm
if you try the circuit, u will see that it fully complies with what it specified in the question ;)
Post by: mdwael on May 26, 2010, 03:16:50 pm
Post by: jellybeans on May 26, 2010, 03:19:10 pm
2a) Much of the energy islost to overcome friction resisting its motion.
6)attached
hey just wondering.. isnt an image from a mirror the same size as the object?
Post by: holtadit on May 26, 2010, 03:19:55 pm
hey just wondering.. isnt an image from a mirror the same size as the object?
yes.
Post by: guMnam on May 26, 2010, 03:20:04 pm
Post by: Weaam on May 26, 2010, 03:21:51 pm
http://thenightdreamer.wordpress.com/2010/01/23/rutherford-scattering/LOVE the presentation! :)
See my website above
Its AWESOME!
Right on! ;)
Post by: Ghost Of Highbury on May 26, 2010, 03:24:03 pm
Can anyone please help me with June 2009. 9 (b)? And also Q 11 (b)? THANKS
I dunno how to prepare to phy, I've done overall almost all papers from 2002 onwards. Should I read the theory or repeat the papers (since I didnt do them all today, did them in 3 or 4 months). A lil advice wud b appreciated!
9B) red-->blue-->green-->yellow
ATTACHED
Post by: tunnellord on May 26, 2010, 03:26:01 pm
Quote
okay guys if speed of a moving object is constant then the acceleration is 0.......i noe i m rite.....but is resultant force and acceleration the same thing
Yes u are right about speed.
However, resultant force causes an accelleration. it is not the same
Post by: Ghost Of Highbury on May 26, 2010, 03:26:22 pm
okay guys if speed of a moving object is constant then the acceleration is 0.......i noe i m rite.....but is resultant force and acceleration the same thing ???
If the acceleration = 0, meaning the resultant force = 0. provided the body is already in motion.
Post by: rhea on May 26, 2010, 03:27:36 pm
Post by: Ivo on May 26, 2010, 03:29:30 pm
can someone draw me the circuit for question 8 (a) in May june 2008 summer paper 3 physics second variant?
Sorry for the rubbish diagram!
Post by: guMnam on May 26, 2010, 03:30:58 pm
aaa so ht means if a object is moving its not important tht a resultant force is acting on it....???? i m really confused....i think tht acceleraion is 0...but there is a resultant force becaz object is moving in a direction...in a straioght line....steady speed..
If the acceleration = 0, meaning the resultant force = 0. provided the body is already in motion.
Post by: Ivo on May 26, 2010, 03:32:13 pm
aaa so ht means if a object is moving its not important tht a resultant force is acting on it....???? i m really confused....i think tht acceleraion is 0...but there is a resultant force becaz object is moving in a direction...in a straioght line....steady speed..
OK, here:
No resultant force: either object at rest, or object moving at CONSTANT speed.
Resultant force: acceleration at the same direction as resultant force.
Got that? :D
Post by: J.Darren on May 26, 2010, 03:32:34 pm
can someone tele how to draw a simple version of a spring balance?http://visual.merriam-webster.com/images/science/measuring-devices/measure-weight/spring-balance.jpg
Post by: holtadit on May 26, 2010, 03:32:52 pm
Can you list all the COMMON IGCSE Physics Experiments we should know....
Much appreciated man ! ;)
Post by: guMnam on May 26, 2010, 03:33:04 pm
Yes u are right about speed.so if accelaration is 0...resultant force is 0???
However, resultant force causes an accelleration. it is not the same
Post by: Ivo on May 26, 2010, 03:34:09 pm
so if accelaration is 0...resultant force is 0???
f=ma Assuming mass is constant, if acc. is 0, then resultant force is 0. That's correct.
Post by: Malak on May 26, 2010, 03:39:45 pm
thx
Post by: Ghost Of Highbury on May 26, 2010, 03:42:13 pm
A@di. From 2009 onwards the first question is ALWAYS experimental. They ask us to plan some experiment.
Can you list all the COMMON IGCSE Physics Experiments we should know....
Much appreciated man ! ;)
Its difficult to tell, could be.
1) Find the specific heat capacity of a substance with few details given
2) Use micrometer/vernial caliper to find the thickness of something
3) Ray experiments involving prism/glass block and pins
4) Pendulum experiments.
5) Calculating the speed of sound (Gun fire/stop watch)
6) Usage of gates to operate firealarm etc. (Diagrams and details)
7) Electrical experiments involving voltmeters and ammeters , find the resistance in parallel and series etc.
8) Usage of ticker-tape timer to calculate the acceleration of objects.
9) CRO displaying a graph, and questions asked about the y-gain, and changing the brightness or the time-base control.
10) Hooke's law experiment.
Good luck
Post by: WARRIOR on May 26, 2010, 03:43:49 pm
Its difficult to tell, could be.
1) Find the specific heat capacity of a substance with few details given
2) Use micrometer/vernial caliper to find the thickness of something
3) Ray experiments involving prism/glass block and pins
4) Pendulum experiments.
5) Calculating the speed of sound (Gun fire/stop watch)
6) Usage of gates to operate firealarm etc. (Diagrams and details)
yo adi
i think i lost 5 marks in total p6 and p1
any chances of an A*?
Post by: Ghost Of Highbury on May 26, 2010, 03:44:31 pm
yo adi
i think i lost 5 marks in total p6 and p1
any chances of an A*?
Don't lose more than 5 marks in paper 3. A* surely.
Post by: WARRIOR on May 26, 2010, 03:45:09 pm
Don't lose more than 5 marks in paper 3. A* surely.ouch
5 marks max?
Post by: thenewkid™ on May 26, 2010, 03:45:46 pm
Whats the difference between Electromagnetism and Electro magnetic induction?electromagnetic induction is the emf induced due to a magnetic field
thx
wheras an electromagnet is a magnet which can be switched on and off
and is made due to the magnetic field of a current
hope this helped
Post by: Ghost Of Highbury on May 26, 2010, 03:47:19 pm
ouch
5 marks max?
Don't lose more than 5 marks ...its good to be on the safer side.
Post by: Malak on May 26, 2010, 03:47:57 pm
electromagnetic induction is the emf induced due to a magnetic field
wheras an electromagnet is a magnet which can be switched on and off
and is made due to the magnetic field of a current
hope this helped
Thx..:D
Another thing...When does the wire/coil watever cuts the magnetic field..When it is vertical or horizontal ???
Post by: ambitious94 on May 26, 2010, 03:48:38 pm
9B) red-->blue-->green-->yellowcan u plz temme y the others r NOT THE ANSWER...I'd really appreciate it. I mean current flows thru all of them doesnt it?
ATTACHED
What does a full-wave rectification circuit look like?
THANKS :)
Post by: WARRIOR on May 26, 2010, 03:48:58 pm
thanks for all ur help
i hope ur heere all day incase i need anything
ima work my but off all night 2day !
Post by: M'i'D'o on May 26, 2010, 03:49:39 pm
a steel bar is hanged near an electromagnet....
A ( attract attract )
B ( attract repel )
C ( repel attract )
D ( repel repel )
Post by: Ghost Of Highbury on May 26, 2010, 03:52:18 pm
can u plz temme y the others r NOT THE ANSWER...I'd really appreciate it. I mean current flows thru all of them doesnt it?
What does a full-wave rectification circuit look like?
THANKS :)
B and D is black to red. C, the circuit aint complete, it wil never reach the lower terminal.
Post by: Ghost Of Highbury on May 26, 2010, 03:52:38 pm
hey everybody there is a question in paper 1 physics i was solving yesterday while studying...
a steel bar is hanged near an electromagnet....
A ( attract attract )
B ( attract repel )
C ( repel attract )
D ( repel repel )
Paper link please.
Post by: J.Darren on May 26, 2010, 03:52:54 pm
Thx..:D- When a current carrying wire / coil goes between the magnetic field.
Another thing...When does the wire/coil watever cuts the magnetic field..When it is vertical or horizontal ???
- When a magnet is pushed in / out of the coil.
- When a wire goes across the magnetic field.
- When an electromagnet is placed right next to a solenoid, it only cuts the magnetic field at the instance when it is being switched on and off.
Post by: mdwael on May 26, 2010, 03:53:42 pm
Sorry for the rubbish diagram!
You saved my life! :)
Post by: Adzel on May 26, 2010, 03:55:10 pm
hey everybody there is a question in paper 1 physics i was solving yesterday while studying...
a steel bar is hanged near an electromagnet....
A ( attract attract )
B ( attract repel )
C ( repel attract )
D ( repel repel )
A ( attract attract )...Im very sure! ;)
Post by: WARRIOR on May 26, 2010, 03:55:46 pm
Thx..:D
Another thing...When does the wire/coil watever cuts the magnetic field..When it is vertical or horizontal ???
it depends
it it cuts at both but maximum cutting is whn its horizontall ( whn voltage induceed is max ) ..it exactly stops cutting whn its prefectly VERTICAL ( this is whn teh voltage induced is 0 )
( motor affect ) of coil
Post by: Ivo on May 26, 2010, 03:56:34 pm
A ( attract attract )...Im very sure! ;)
Beware, it says steel...
Post by: NidZ- Hero on May 26, 2010, 03:56:50 pm
explanation
if a magnet is moved in or out of a coil a current is induced in de coil lke if de induced current turns the coil into a weak electromagnet whose N pole opposses de approachin N pole of de magnet when de magnet is induced is pulled out of de coil the induced current alters de dirtection and de poles of de coil r reversed then de de tmme de coil attract de magnet as its pulled away. so once again de the change is opppoesd
Post by: omair on May 26, 2010, 03:58:37 pm
Post by: Ivo on May 26, 2010, 03:59:42 pm
which and why expands more water or ice if heated with same ammount of heat
Water defo. Cos inter-molecular bonds of water is slightly weaker than solids, so they are able to expand more (the molecules).
Post by: Vin on May 26, 2010, 04:01:15 pm
which and why expands more water or ice if heated with same ammount of heat
hmmm .. summer 09 Q 2a) huh :P
Post by: holtadit on May 26, 2010, 04:03:56 pm
Statistically, in May/June of the past three years - 21.66666667% of all candidates got an A*. This is an average I worked put from offical data.
Statistically, in Oct/Noc of the past three years - 18.25% of all candidates got an A*.
Thus WE have a better chance of getting an A* than our winter session counterparts.
People lets do this and get it right !!!
Post by: ambitious94 on May 26, 2010, 04:04:54 pm
Post by: Ivo on May 26, 2010, 04:05:34 pm
Okay people here is a morale booster :
Statistically, in May/June of the past three years - 21.66666667% of all candidates got an A*. This is an average I worked put from offical data.
Statistically, in Oct/Noc of the past three years - 18.25% of all candidates got an A*.
Thus WE have a better chance of getting an A* than our winter session counterparts.
People lets do this and get it right !!!
How does A* at IGCSE work? Is it by set grade boundaries or is it like first 20% get A*. So if for instance Bio P3 was super hard, maybe I stand a better chance of getting A* if everyone else found it hard?
Post by: holtadit on May 26, 2010, 04:07:30 pm
How does A* at IGCSE work? Is it by set grade boundaries or is it like first 20% get A*. So if for instance Bio P3 was super hard, maybe I stand a better chance of getting A* if everyone else found it hard?
The top 10th percetile get A*s
If it was a hard paper then chances are that 10th percentile will be big.
Post by: ambitious94 on May 26, 2010, 04:08:18 pm
Okay people here is a morale booster :
Statistically, in May/June of the past three years - 21.66666667% of all candidates got an A*. This is an average I worked put from offical data.
Statistically, in Oct/Noc of the past three years - 18.25% of all candidates got an A*.
Thus WE have a better chance of getting an A* than our winter session counterparts.
People lets do this and get it right !!!
LOL...Ari or Ben (whichever one's ur name XD)..i think u shud chillax n so sum phy ryt now than work out averages!! LOL...The way u've been askin questions n answerin them...ur gonna do gr8 pal!
Post by: Ivo on May 26, 2010, 04:09:19 pm
The top 10th percetile get A*s
If it was a hard paper then chances are that 10th percentile will be big.
What's 10th percentile, and how does that relate to the 21.666666667% you worked out? Is the 20% of all candiates get A* or what, and what's percentile. Sorry for being dumb :(
Post by: WARRIOR on May 26, 2010, 04:11:19 pm
look if there is a ciruit with a resisor in series and after the resistor comes two PARALEL resistors .
Is it true that if the series resistor has a higher resistance that both the parallel , the current goes thro sreies resitor first?
because the voltge has to be used up in teh series resistor so that we could calculate the voltage around the parallel ones?
Post by: Ghost Of Highbury on May 26, 2010, 04:15:43 pm
AAADII..EHM ( i need u to imagine over here )This is absolutely bizarre , please provide a diagram.
look if there is a ciruit with a resisor in series and after the resistor comes two PARALEL resistors .
Is it true that if the series resistor has a higher resistance that both the parallel , the current goes thro sreies resitor first?
because the voltge has to be used up in teh series resistor so that we could calculate the voltage around the parallel ones?
Post by: omair on May 26, 2010, 04:17:37 pm
CRO displaying a graph, and questions asked about the y-gain, and changing the brightness or the time-base control.
hey any genius find and tell about it
Post by: guMnam on May 26, 2010, 04:18:08 pm
This is absolutely bizarre , please provide a diagram.i was just sayin tht...
Post by: Ghost Of Highbury on May 26, 2010, 04:18:57 pm
Usage of ticker-tape timer to calculate the acceleration of objects.
CRO displaying a graph, and questions asked about the y-gain, and changing the brightness or the time-base control.
hey any genius find and tell about it
Ticker-tape = http://www.physicsphenomena.com/TickerTape.html
http://www.practicalphysics.org/go/Experiment_310.html
CRO = the time base produces the x-axis. VOltage , the y-axis. when these combine they form a curve. if the voltage is ac , it will form something like the sine curve....say the Y-gain is set at 5V/cm. so in the graph if its 15Volts.. the point will move up 3 cms
Post by: Malak on May 26, 2010, 04:20:23 pm
Thx
Post by: holtadit on May 26, 2010, 04:20:51 pm
Q: Describe how the energy from the sun becomes stored energy in water behind a dam.[3]
Thx
Look at the MS.
Seriously. ;)
Post by: Vin on May 26, 2010, 04:22:32 pm
AAADII..EHM ( i need u to imagine over here )
look if there is a ciruit with a resisor in series and after the resistor comes two PARALEL resistors .
Is it true that if the series resistor has a higher resistance that both the parallel , the current goes thro sreies resitor first?
because the voltge has to be used up in teh series resistor so that we could calculate the voltage around the parallel ones?
LMAO !! XD .. a resisor in series ??
Post by: MasterMath on May 26, 2010, 04:22:56 pm
Q: Describe how the energy from the sun becomes stored energy in water behind a dam.[3]Energy from the sun (moved to earth by radiation) increases the temperature of water .. Thus making it evaporate to gas which increases its G.P.E then the vapor falls as rain which can be used in dams to move turbines etc.
Thx
Post by: Malak on May 26, 2010, 04:26:05 pm
LMAO !! XD .. a resisor in series ??I guess..this is wat it means maybe ?
Post by: WARRIOR on May 26, 2010, 04:26:50 pm
In order to find the voltages accros the parallel resistors. u have to subtbract the voltage being used up in the series and the voltage is then given to teh 2 parallel resistors
well what if the resistance of the series resistor is higher than total resistance of parallel ristors?
does the current flow thro the parallel first then?
Post by: thenewkid™ on May 26, 2010, 04:30:45 pm
Energy from the sun (moved to earth by radiation) increases the temperature of water .. Thus making it evaporate to gas which increases its G.P.E then the vapor falls as rain which can be used in dams to move turbines etc.r u sure???
Post by: Ghost Of Highbury on May 26, 2010, 04:32:36 pm
look. ( spaces are resistors )
In order to find the voltages accros the parallel resistors. u have to subtbract the voltage being used up in the series and the voltage is then given to teh 2 parallel resistors
well what if the resistance of the series resistor is higher than total resistance of parallel ristors?
does the current flow thro the parallel first then?
ok suppose V = 10V
Series Resistor = 3ohms
Each parallel Resistor = 2ohms
thus, combined parallel resistance = 1 ohm.
so the parallel resistors get , 1/4*10 = 2.5Volts and the series resistor gets = 7.5Volts
Post by: Adzel on May 26, 2010, 04:34:36 pm
hey everybody there is a question in paper 1 physics i was solving yesterday while studying...
a steel bar is hanged near an electromagnet....
A ( attract attract )
B ( attract repel )
C ( repel attract )
D ( repel repel )
Guys....don't you think that this question is familiar....
Post by: Ivo on May 26, 2010, 04:35:26 pm
Guys....don't you think that this question is familiar....
To what? Can someone confirm whether the answer to that question is B?
Post by: Adzel on May 26, 2010, 04:37:54 pm
To what?
Today's ***m
Post by: holtadit on May 26, 2010, 04:39:21 pm
Today's ***m
Yeah.....
Post by: thenewkid™ on May 26, 2010, 04:39:40 pm
Guys....don't you think that this question is familiar....
somthin i ws doing some hrs ago
right
Post by: Ivo on May 26, 2010, 04:40:36 pm
hey everybody there is a question in paper 1 physics i was solving yesterday while studying...
a steel bar is hanged near an electromagnet....
A ( attract attract )
B ( attract repel )
C ( repel attract )
D ( repel repel )
So is the answer B?
Post by: WARRIOR on May 26, 2010, 04:40:59 pm
ok suppose V = 10Vi seee
Series Resistor = 3ohms
Each parallel Resistor = 2ohms
thus, combined parallel resistance = 1 ohm.
so the parallel resistors get , 1/4*10 = 2.5Volts and the series resistor gets = 7.5Volts
i had this weird thing in my mind...hmmm
cool thx
Post by: MasterMath on May 26, 2010, 04:42:14 pm
Post by: Ivo on May 26, 2010, 04:43:18 pm
So is the answer B?
Guys, do you realise this question is different to the "***m"
Post by: thenewkid™ on May 26, 2010, 04:44:33 pm
i can even draw the diagram
Post by: Ivo on May 26, 2010, 04:45:38 pm
yes its the same 1
i can even draw the diagram
No, this question is about STEEL...
Post by: Raywin on May 26, 2010, 04:46:25 pm
Using a 40w heater, 16.3g of ice is melted in 2.0 minutes. The heater is then switched off. In a further 2.0 minutes, 2.1g of ice is melted. Calculate the value of the specific latent heat of fusion of ice from these results.
Post by: Malak on May 26, 2010, 04:48:29 pm
Anyone? thx :D
Post by: ambitious94 on May 26, 2010, 04:49:48 pm
yes its the same 1guys what's all the fuss about. It isnt even the same thing n ur makin it kinda obvious!
i can even draw the diagram
The answer is B.
N I solved this question in a pastpaper myself! (Bet u all did XD) :D
Post by: Ivo on May 26, 2010, 04:51:07 pm
guys what's all the fuss about. It isnt even the same thing n ur makin it kinda obvious!
The answer is B.
N I solved this question in a pastpaper myself! (Bet u all did XD) :D
Is it because first time, it attracts. But when current is reversed, steel is magentically hard so hangs on to magnetism, so it repels, cos if forms poles?
Post by: Shazizzzle on May 26, 2010, 04:56:23 pm
Hey guys... doubt. O/N 08 Q 5(c) :/ The paper doesnt open for some reason. So heres the Q
Using a 40w heater, 16.3g of ice is melted in 2.0 minutes. The heater is then switched off. In a further 2.0 minutes, 2.1g of ice is melted. Calculate the value of the specific latent heat of fusion of ice from these results.
Using the formula for latent heat, P X T = mL, we can find the spc. lt. ht.
Now, 16.3 g was melted USING THE HEATER.
Without the heater, 2.1g of ice melted in the same. That was due to the heat from surroundings!
So, for the mass the heater itself melted= heater - without heater
= 16.3 - 2.1
=14.2
time= 2 min = 60 x 2 = 120 s
Now, p X t = mL
40 X 120 = 14.2 X L
4800/14.2 = L
L= 338.028
thus, L = 338 J/g
Post by: Shazizzzle on May 26, 2010, 04:57:08 pm
We obviously cannot complete the entire syllabus in one day.
Post by: Raywin on May 26, 2010, 04:58:33 pm
Using the formula for latent heat, P X T = mL, we can find the spc. lt. ht.
Now, 16.3 g was melted USING THE HEATER.
Without the heater, 2.1g of ice melted in the same. That was due to the heat from surroundings!
So, for the mass the heater itself melted= heater - without heater
= 16.3 - 2.1
=14.2
time= 2 min = 60 x 2 = 120 s
Now, p X t = mL
40 X 120 = 14.2 X L
4800/14.2 = L
L= 338.028
thus, L = 338 J/g
Wait. I thot the Q said that AFT 16.3g of ice is melted the heater is turned off.. so why r we subtracting 2.1 from 16.3?? Thts wht i dont get!! Thx a lot! :)
Post by: Adzel on May 26, 2010, 04:59:54 pm
So... What're you guys doing for Paper 3?
We obviously cannot complete the entire syllabus in one day.
Im actually going through my previously solved pastpapers (2009 - 2002) + Reading my text book, how about you?
Post by: MasterMath on May 26, 2010, 05:00:12 pm
Thanks!
Post by: holtadit on May 26, 2010, 05:00:26 pm
So... What're you guys doing for Paper 3?
We obviously cannot complete the entire syllabus in one day.
REVISION, REVISION and lets see MORE REVISION !! :P
Post by: Malak on May 26, 2010, 05:03:41 pm
Q: draw wavefronts to show what happens after the waves strike the surfacehelp??
Anyone? thx :D
Post by: Shazizzzle on May 26, 2010, 05:03:51 pm
Wait. I thot the Q said that AFT 16.3g of ice is melted the heater is turned off.. so why r we subtracting 2.1 from 16.3?? Thts wht i dont get!! Thx a lot! :)
Yeah, well, the heater gave it the activation energy to BEGIN melting!
When the heater stopped, the melting that took place for the next two minutes, was by the heat energy provided by the surroundings.
That heat energy from the surroundings was also provided WITH the heater, so the 16.3 g was a combination of melting due to heater, AND melting due to heat from surroundings.
Therefore, to calculate the mass melted by THE HEATER ITSELF, we subtracting the reading WITHOUT HEATER, from the reading for both. :)
Post by: ambitious94 on May 26, 2010, 05:04:31 pm
Is it because first time, it attracts. But when current is reversed, steel is magentically hard so hangs on to magnetism, so it repels, cos if forms poles?DITTO :)
Post by: Adzel on May 26, 2010, 05:06:11 pm
Raul's Mother Is Visiting Uncle Xavi's Garden
Post by: Fastal on May 26, 2010, 05:06:25 pm
describe the use of water waves to show-
(i)reflection at a plane surface
(ii)refraction due to a change of speed
(iii)diffraction produced by wide and narrow gaps[understand the diffraction part]
-interpret relection, refraction and diffraction using wave theory
Post by: rhea on May 26, 2010, 05:06:53 pm
Guys Remember this,and whats that?? :-\ :-\ :-\
Raul's Mother Is Visiting Uncle Xavi's Garden
Post by: ambitious94 on May 26, 2010, 05:07:10 pm
Anyone can help me with Vernier calipers? ive never done it and never even heard about it in school ??? So anyone can tell me how to use it or anything ?http://www.complore.com/using-vernier-calipers-and-micrometer-screw-gauge-0
Thanks!
Found it awesum!
Post by: Raywin on May 26, 2010, 05:07:51 pm
Yeah, well, the heater gave it the activation energy to BEGIN melting!
When the heater stopped, the melting that took place for the next two minutes, was by the heat energy provided by the surroundings.
That heat energy from the surroundings was also provided WITH the heater, so the 16.3 g was a combination of melting due to heater, AND melting due to heat from surroundings.
Therefore, to calculate the mass melted by THE HEATER ITSELF, we subtracting the reading WITHOUT HEATER, from the reading for both. :)
Ohh so u mean to say tht 16.3g of ice was melted by the heater for 2 min but this want enough to melt the ENTIRE 16.3g and since the heater was turned off, the rest of the unmelted ice (2.1g) heated because of heat from the surroundings? OHHH... i get it now!! Thanks a lot!!
+rep ;)
Post by: rhea on May 26, 2010, 05:08:26 pm
how do you get to know which side is the norh and the south pole when the direction of current in a solenoid is given?
Post by: Adzel on May 26, 2010, 05:08:46 pm
and whats that?? :-\ :-\ :-\
The Electro magnetic spectrum....easy way to remember
Post by: Shazizzzle on May 26, 2010, 05:10:42 pm
hey
how do you get to know which side is the norh and the south pole when the direction of current in a solenoid is given?
Right hand grip rule.
When the thumb is the direction of current, the coiled fingers represent the direction of magnetic field around it.
When the coiled fingers are the current, as in a solenoid, then the thumb points north.
Post by: ambitious94 on May 26, 2010, 05:11:00 pm
what do we have to know for this part of the syllabus? do we need to know Hugyens constructions and stuff?NOPE NOPE NOPE...CIE keeps it simple fortunately...
describe the use of water waves to show-
(i)reflection at a plane surface
(ii)refraction due to a change of speed
(iii)diffraction produced by wide and narrow gaps[understand the diffraction part]
-interpret relection, refraction and diffraction using wave theory
You just have to know the use of ripple tanks to demonstrate these properties of waves, diagrams representing them, changes in wavelength, speed, frequency (if any).....and be able to draw all of them. That's all =D
Post by: Adzel on May 26, 2010, 05:11:44 pm
hey
how do you get to know which side is the norh and the south pole when the direction of current in a solenoid is given?
(http://1.bp.blogspot.com/_PyvjcvYfRLk/SFnpDI55a4I/AAAAAAAAAEQ/hiFS_Z2Nwk0/s400/Right-Hand-Grip-Rules.png)
Post by: ambitious94 on May 26, 2010, 05:12:11 pm
Right hand grip rule.wow I didnt know that...thanks for sharing :)
When the thumb is the direction of current, the coiled fingers represent the direction of magnetic field around it.
When the coiled fingers are the current, as in a solenoid, then the thumb points north.
Post by: Weaam on May 26, 2010, 05:12:22 pm
Reaaallly urgent, i cant seem to get an answer to it!
ill +rep if u help ::)
Post by: Fastal on May 26, 2010, 05:12:36 pm
NOPE NOPE NOPE...CIE keeps it simple fortunately...thanks, can i also get a confirmation from another person just for my mental sanity XP, cuz i am spooked, my teacher told me yes i have to know hugyens construction and stuff
You just have to know the use of ripple tanks to demonstrate these properties of waves, diagrams representing them, changes in wavelength, speed, frequency (if any).....and be able to draw all of them. That's all =D
Post by: ionsupreme on May 26, 2010, 05:14:58 pm
use the parralellogram method to get your resultant.
Question, can anyone solve and scan ,
or at least explain how to do it, (dont worry i'll understand)
Post by: Moonlyte on May 26, 2010, 05:18:25 pm
Post by: Fastal on May 26, 2010, 05:20:29 pm
what do we have to know for this part of the syllabus? do we need to know Hugyens constructions and stuff?
describe the use of water waves to show-
(i)reflection at a plane surface
(ii)refraction due to a change of speed
(iii)diffraction produced by wide and narrow gaps[understand the diffraction part]
-interpret relection, refraction and diffraction using wave theory
GUYS CAN I get a confirmation that ang3ls right????
Post by: NidZ- Hero on May 26, 2010, 05:20:51 pm
n (b)
Post by: Malak on May 26, 2010, 05:23:08 pm
Post by: Adzel on May 26, 2010, 05:27:59 pm
yo master help me wid diz m/j 2005 q8 (a)
n (b)
Post by: Ghost Of Highbury on May 26, 2010, 05:30:21 pm
If in exam we are told to draw a thermocouple...Is this form of diargram correct??
yes.
Post by: Adzel on May 26, 2010, 05:30:23 pm
If in exam we are told to draw a thermocouple...Is this form of diargram correct??
Nope...Draw this,
(http://i.ehow.com/images/a05/4u/tr/thermocouple-200X200.jpg)
Post by: Malak on May 26, 2010, 05:32:07 pm
Post by: Ghost Of Highbury on May 26, 2010, 05:33:06 pm
Can anyone draw how the picture will loook like after parts a i,ii are done in o/n 09 Q 4!
Reaaallly urgent, i cant seem to get an answer to it!
ill +rep if u help ::)
attached
Post by: Ghost Of Highbury on May 26, 2010, 05:33:37 pm
Post by: mdwael on May 26, 2010, 05:35:24 pm
Post by: Malak on May 26, 2010, 05:36:28 pm
of course u can that, it has the hot junction / cold junction the wires..and the meter..Okay...thx Thats muchh eaiser :D
Q1 both parts..
http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_32.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_32.pdf)
Post by: Malak on May 26, 2010, 05:40:47 pm
can someone explain me question 11 (the last one) in oct/nov paper 3 physics year 2007? pls save my life cuz tommorow is my exam :-[
For part a
First you take counter readings without any source or absorber only detector...This is the background
Then you take reading with Source and detector
Then take reading with source , detector Plus absorber which is aluminium in this case (one sheet at a time..u keep adding and take reading)
Finally subtract the background reading from the result
Part b:
The counter readind decreases as the thickness of aluminium is increased
Post by: holtadit on May 26, 2010, 05:41:32 pm
Post by: Malak on May 26, 2010, 05:42:04 pm
Can someone please explain what voltage drop is ???2009 nov ?:P
Post by: Ghost Of Highbury on May 26, 2010, 05:43:17 pm
Okay...thx Thats muchh eaiser :D
Q1 both parts..
http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_32.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_32.pdf)
I think you should measure the angle between the vertical to the fixed point and B.
Do this with a large protractor fixed to a board behind the swinging weight.
The weight will be moving v slowly at the endpoints and should be easy to measure.
It is the largest distance from the centre or rest or hanging point
you can also callit an angle in the case of a pendulum
^^Astar's Answers^^
Post by: holtadit on May 26, 2010, 05:44:48 pm
2009 nov ?:P
NOOOOO !!! ::) ::) ::)
Post by: aoas on May 26, 2010, 05:45:02 pm
http://www.gcse.com/physics.htm
Post by: Malak on May 26, 2010, 05:47:16 pm
NOOOOO !!! ::) ::) ::)
Lol...Umm I think its jst First voltage - second voltage ( maybe..)
Post by: Helium on May 26, 2010, 05:50:24 pm
If anyone would mind telling me how the find specific latent heat of vaporisation.
When there is watt heater
I know energy needed to boil water at 100= 2300000(J/kg) * mass in Kg
Post by: Weaam on May 26, 2010, 05:52:49 pm
attachedAre you sure??
and it doesnt have part (i) in it ..
Post by: Malak on May 26, 2010, 05:54:10 pm
Q9: Part c all ::)
Post by: Ghost Of Highbury on May 26, 2010, 05:55:56 pm
The overall voltage reduced from 22K Volts due to the resistance of the wire, till it reaches the receiving end.
I know this is confusing sh*t, it had appeared in my paper! nov 09! V = 2.5*3 = 7.5
from wiki "For example, an electric space heater may very well have a resistance of ten ohms, and the wires which supply it may have a resistance of 0.2 ohms, about 2% of the total circuit resistance. This means that 2% of the supplied voltage is actually being lost by the wire itself."
Post by: Ghost Of Highbury on May 26, 2010, 05:58:06 pm
Are you sure??
and it doesnt have part (i) in it ..
yes sure, oh abt the (i) part..both towards the center..centrifugal force..
Post by: Shazizzzle on May 26, 2010, 06:02:33 pm
Post by: Weaam on May 26, 2010, 06:03:43 pm
Are we screwed? :DIf ur talking about the exam then yes, i believe we are
Post by: Ivo on May 26, 2010, 06:05:56 pm
Post by: Weaam on May 26, 2010, 06:06:25 pm
yes sure, oh abt the (i) part..both towards the center..centrifugal force..ok then, thank yoooou! :D
Post by: Ghost Of Highbury on May 26, 2010, 06:10:07 pm
From 06 may june,
If anyone would mind telling me how the find specific latent heat of vaporisation.
When there is watt heater
I know energy needed to boil water at 100= 2300000(J/kg) * mass in Kg
0.05g = 1s
Xg = 20X seconds
120*20x = specific heat of vaporization * X
specific heat ........ = 2400X/X = 2400kJ/kg
Post by: 33oomar on May 26, 2010, 06:10:29 pm
Q2 PAPER 3 MAY/JUNE 2007
CAN SOMEONE PLEASE EXPLAIN IT TO ME ???
Post by: Ghost Of Highbury on May 26, 2010, 06:16:11 pm
Hey, please can someone explain how you work out Q6)a)iii) for w09. Link for paper is: http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_31.pdf
F = pressure * area.
b4 weights : 1.05 × 105 × 5.0 × 10-3 = 525N
after weights : 1.4 × 105 × 5.0 × 10-3 = 700N
700-525 = 175N
Post by: 2010 on May 26, 2010, 06:17:48 pm
When gamma cannot be stopped by lead why is it stored in lead containers.....I know that lead reduces the intensity of gamma but it doesn't stop it does it?
Post by: Ivo on May 26, 2010, 06:23:50 pm
F = pressure * area.
b4 weights : 1.05 × 105 × 5.0 × 10-3 = 525N
after weights : 1.4 × 105 × 5.0 × 10-3 = 700N
700-525 = 175N
OK thanks a lot A@di, very clear explanation. Just wanted to know how to explain, for same paper and question, part b)i), I know the volume increases when temp. increases, but is it because gas molecules expand and so become less dense, so occupy larger volume, or is it because kinetic energy of mol. are greater, therefore more hits with molecules.
Post by: M'i'D'o on May 26, 2010, 06:25:34 pm
what is the GREATEST danger if there is a wire kept uninsulated in a room ??
is it fire or electric shock or any other ??
plz reply fast
Post by: ambitious94 on May 26, 2010, 06:26:15 pm
Whoever predicted we're screwed wasnt lying! XD
I havent actually studied the portion! UGHHHH
Post by: Ghost Of Highbury on May 26, 2010, 06:27:57 pm
OK thanks a lot A@di, very clear explanation. Just wanted to know how to explain, for same paper and question, part b)i), I know the volume increases when temp. increases, but is it because gas molecules expand and so become less dense, so occupy larger volume, or is it because kinetic energy of mol. are greater, therefore more hits with molecules.
the MOLECULES dont expand, their intermolecular SPACE increases because as they have more KE.
Post by: Ivo on May 26, 2010, 06:33:10 pm
the MOLECULES dont expand, their intermolecular SPACE increases because as they have more KE.
OK, so let's clear this up:
Expansion: is due to the expansion of gas (molecules get further apart) and forces the piston out, as the volume increases.
Pressure: an increase in pressure is due to molecules gaining more ke and so hit the sides more frequently and with more force, so pressure increases.
However, I don't know how to explain the relationship of volume with pressure for constant temperature. Please explain.
Post by: Ghost Of Highbury on May 26, 2010, 06:39:02 pm
Can anyone plzzzzzzzzzzzzzzzzzzzz plzzzzzzzzzzzzzzz explain me June 09 Q 11 b!!!
Whoever predicted we're screwed wasnt lying! XD
I havent actually studied the portion! UGHHHH
SHould be perpendicular to the magnetic field. Negative plate opposite the deflection. So that the alpha particle gets attracted to the negative and cancels the deflection..
@Ivo = When pressure increases , volume decreases. Consider a syringe, if u apply pressure, the volume of air in the syringe decreases...inversely propotional
Post by: Ghost Of Highbury on May 26, 2010, 06:39:39 pm
hey everyone....
what is the GREATEST danger if there is a wire kept uninsulated in a room ??
is it fire or electric shock or any other ??
plz reply fast
Electric shock?
Post by: Malak on May 26, 2010, 06:41:54 pm
thx
http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_32.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_32.pdf)
Post by: MasterMath on May 26, 2010, 06:42:20 pm
FAST PLEASE :)
Post by: Baladya on May 26, 2010, 06:42:36 pm
Q6)b)ii) Why does it stay the same? Isnt it supposed to be constant?
Thanks :)
Post by: Ghost Of Highbury on May 26, 2010, 06:48:20 pm
can someone verify this for me ? The Advantage of using a CRO over a Voltmeter is because CRO produces more accurate reading as it consumes less curent?
FAST PLEASE :)
yes, by adjusting the time-base and the y-gain, more accurate results.
Post by: the_grim_reaper on May 26, 2010, 06:52:45 pm
Electric shock?
Has to be. It was an MCQ in today's paper 1. I did electric shock..
Anyway, I've got just one question today, like you know when we heat something, after we stop, we take the greatest temperature rise. In question 5 (c), November 2008, why are we subtracting 16.3 from 2.1?? I mean will the heater's heat not melt more ice after the it's switched off?? (If this question has been answered, just tell me the page number)
Secondly, say if we're asked to find the latent heat of vaporisation of water, so we calculate the energy given AFTER it reaches the boil right?? Similar in ice like we calculate the amount of heat given AFTER it melts a little??? And like can a joule meter be used in a circuit like say we're using a heater. As soon as the water starts to boil, you switch on the joule meter. Basically, what I want to know is that will current flow through if it is not switched on???? (So we can switch it on at any time and calculate the energy only for that interval??)
Post by: Adzel on May 26, 2010, 06:53:15 pm
Electric shock?
yes...
Post by: Shazizzzle on May 26, 2010, 06:54:50 pm
Has to be. It was an MCQ in today's paper 1. I did electric shock..
Anyway, I've got just one question today, like you know when we heat something, after we stop, we take the greatest temperature rise. In question 5 (c), November 2008, why are we subtracting 16.3 from 2.1?? I mean will the heater's heat not melt more ice after the it's switched off?? (If this question has been answered, just tell me the page number)
Secondly, say if we're asked to find the latent heat of vaporisation of water, so we calculate the energy given AFTER it reaches the boil right?? Similar in ice like we calculate the amount of heat given AFTER it melts a little??? And like can a joule meter be used in a circuit like say we're using a heater. As soon as the water starts to boil, you switch on the joule meter. Basically, what I want to know is that will current flow through if it is not switched on???? (So we can switch it on at any time and calculate the energy only for that interval??)
Page 137 for first one.
Post by: rhea on May 26, 2010, 07:02:31 pm
a) split ring
b) slip ring
REPLY SOON!!
urgent!!
Post by: Vin on May 26, 2010, 07:05:16 pm
Any pending ques ?? :P
Good job Aadi, Shazizzzle, Ivo, Kimo, Adzel .. (am i missing someone ?? )
thanks ;) .. for what ?? ..because even I had a couple of small doubts which were solved here
Post by: Vin on May 26, 2010, 07:07:09 pm
what are the advantages of using?
a) split ring
b) slip ring
REPLY SOON!!
urgent!!
ok slip ring is used in AC generators ..
Split ring is used in DC motors and DC generators .. lemme fetch images
A.C. Generators
(http://1.bp.blogspot.com/_jbMoSCDL2ng/SkhFgE5S8xI/AAAAAAAAAPk/wbJAlqquZ-w/s400/ac_generator.gif) (http://www.pbs.org/wgbh/amex/edison/sfeature/images/acdc_inside_generator.gif)
DC Generator
(http://bp3.blogger.com/_PyvjcvYfRLk/SGBwGzICHZI/AAAAAAAAAGo/wZY6YxUJjWU/s400/DC-generator.png)
DC Motor
(http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/imgmag/dcmcur.gif)
Post by: Ivo on May 26, 2010, 07:08:34 pm
http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_31.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_31.pdf)
Q6)b)ii) Why does it stay the same? Isnt it supposed to be constant?
Thanks :)
This question hasn't been answered yet, and I'm stuck on this as well. Many thanks in advance.
Post by: Malak on May 26, 2010, 07:09:14 pm
oooh i see i hav missed a lot here .. :P
Any pending ques ?? :P
Good job Aadi, Shazizzzle, Ivo, Kimo, Adzel .. (am i missing someone ?? )
thanks ;) .. for what ?? ..because even I had a couple of small doubts which were solved here
Hehe yeah a pendin Q ::)
http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_32.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_32.pdf)
Q9 part c all ::)
Post by: mdwael on May 26, 2010, 07:14:26 pm
Post by: Dana on May 26, 2010, 07:32:55 pm
Post by: rhea on May 26, 2010, 07:33:19 pm
ok slip ring is used in AC generators ..
Split ring is used in DC motors and DC generators .. lemme fetch images
A.C. Generators
(http://1.bp.blogspot.com/_jbMoSCDL2ng/SkhFgE5S8xI/AAAAAAAAAPk/wbJAlqquZ-w/s400/ac_generator.gif) (http://www.pbs.org/wgbh/amex/edison/sfeature/images/acdc_inside_generator.gif)
DC Generator
(http://bp3.blogger.com/_PyvjcvYfRLk/SGBwGzICHZI/AAAAAAAAAGo/wZY6YxUJjWU/s400/DC-generator.png)
DC Motor
(http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/imgmag/dcmcur.gif)
could you explain that in a lil detail..as in the slip rings..
Post by: 6394 on May 26, 2010, 07:34:54 pm
i noe de fact dat evaporation is a coollin effect
bt dint gt de othr parts of ms!!!!!!
Post by: Helium on May 26, 2010, 07:37:09 pm
0.05g = 1s
Xg = 20X seconds
120*20x = specific heat of vaporization * X
specific heat ........ = 2400X/X = 2400kJ/kg
Thanks A@di ;D
Post by: Adzel on May 26, 2010, 07:38:12 pm
The function of a slip ring is to make one or more continuous electrical connections from points in a stationary unit to points in a rotating section. Electrical connections on slip rings can be for both power and data signal connections.
Post by: Vin on May 26, 2010, 07:39:46 pm
This question hasn't been answered yet, and I'm stuck on this as well. Many thanks in advance.
ok this is Charles' Law
The volume of a fixed mass of gas is directly proportional to its temperature if the pressure is kept constant
meaning there is an increase in volume due to the temperature rise because the pressure is constant
so here the change in vol. in b)i) is only possible because the pressure is kept constant .. so no change
Post by: mdwael on May 26, 2010, 07:44:06 pm
Post by: Ivo on May 26, 2010, 07:44:49 pm
ok this is Charles' Law
The volume of a fixed mass of gas is directly proportional to its temperature if the pressure is kept constant
meaning there is an increase in volume due to the temperature rise because the pressure is constant
so here the change in vol. in b)i) is only possible because the pressure is kept constant .. so no change
So Boyle's Law is that if temperature is constant, then when volume decreases, pressure increases?
Post by: thenewkid™ on May 26, 2010, 07:46:05 pm
Quote
0625/32/M/J/09 ques 7 b pleazzthe cloth always remains damp because it is dipped in water on both side
i noe de fact dat evaporation is a coollin effect
bt dint gt de othr parts of ms!!!!!!
the energy required for the molecules to evaporate is obtained from the milk
hope this helps
Post by: Adzel on May 26, 2010, 07:47:31 pm
Can someone please explain the whole concept of the LDR for me pleasee?? It's quite confusing.
(http://www.freeimagehosting.net/uploads/0202f627ed.gif)
The animation shows that when the torch is turned on, the resistance of the LDR falls, allowing current to pass through it.
Post by: Weaam on May 26, 2010, 07:48:16 pm
Really Urgent!!
Post by: Ghost Of Highbury on May 26, 2010, 07:48:40 pm
Can anyone tell me what monochromatic light is??
Really Urgent!!
Light of a single frequency.
Post by: NightHawkerr on May 26, 2010, 07:49:34 pm
As Light intensity decreases on LDR, The resistance across it increases, thus V input increases. When V input is more than 0.6 V, the transistor is switched ON, and thus the lamp/ alarm etc. turns ON.
Post by: SuperGenius on May 26, 2010, 07:50:16 pm
hope you can understand my english
Post by: Ivo on May 26, 2010, 07:51:02 pm
Light of a single frequency.
Or just light of one colour!
Post by: Weaam on May 26, 2010, 07:51:33 pm
Light of a single frequency.Thaaaaank yooou!
Post by: thenewkid™ on May 26, 2010, 07:53:00 pm
(different colors hv different wavelengths)
Post by: NightHawkerr on May 26, 2010, 07:53:43 pm
Post by: rhea on May 26, 2010, 07:53:54 pm
@ rhea:
The function of a slip ring is to make one or more continuous electrical connections from points in a stationary unit to points in a rotating section. Electrical connections on slip rings can be for both power and data signal connections.
hey thanks =)
just another doubt:
Ac generator/ DC motor, which one takes half-turns?
Post by: Vin on May 26, 2010, 07:54:01 pm
Hehe yeah a pendin Q ::)
http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_32.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_32.pdf)
Q9 part c all ::)
9 c)i)
ok so the initial temperature of water was 21.1 which rose to 22.9 so the diff. = 22.9-21.1 = 1.8*C
Initial temperature of metal was 100*C and it fell to 22.9*C .. y 100 because it was taken out from boiling water which is 100*C
so diff. = 100 - 22.9 = 77.1*C
ii) Thermal energy(Q) = mass * specific heat capacity * temp. change
= 0.2kg * 4200 J / (kg K) * 1.8*C
= 1512 J
iii) Heat lost by water = heat gained by metal
Q = 1512 J
m = 0.05kg
temp.change = 77.1*C
Q = mc(theta)
c = Q/m(theta)
c = 1512/0.05*77.1
= 392.22
=392 J/kg*C
iv) Heat lost in surroundings
Post by: rhea on May 26, 2010, 07:54:54 pm
Hey one question, A box full of matches.. Does it have internal(thermal) energy or chemical energy?
chemical, i guess.
Post by: Adzel on May 26, 2010, 07:55:09 pm
hey thanks =)
just another doubt:
Ac generator/ DC motor, which one takes half-turns?
Split rings = half turns = DC motor
Post by: thenewkid™ on May 26, 2010, 07:55:39 pm
Hey one question, A box full of matches.. Does it have internal(thermal) energy or chemical energy?chemical energy
sry didnt notice u ppl hd answered
Post by: 8T on May 26, 2010, 07:56:44 pm
chemical energyAre You Sure??
Post by: rhea on May 26, 2010, 07:56:58 pm
Split rings = half turns = DC motor
umm, but arent split rings there to change direction of I so that coil can take full-turns?
Post by: Ivo on May 26, 2010, 07:57:35 pm
umm, but arent split rings there to change direction of I so that coil can take full-turns?
Split rings reverse the direction of current every half-revolution so the coil keeps spinning in one direction, got it?
Post by: Vin on May 26, 2010, 07:57:44 pm
Can someone please explain me questsion 1 b iv part in oct nov 2006 paper 3 physics? what is cork and how do you find its density ???
0625/32/M/J/09 ques 7 b pleazz
i noe de fact dat evaporation is a coollin effect
bt dint gt de othr parts of ms!!!!!!
There is this experiment in oct nov 2006 question 5 (b) how do you carry it out? what do you have to draw, the MS is not clear.. can someone please do it for me?
all answered ??
Post by: rhea on May 26, 2010, 07:59:04 pm
im sorry...just never got this split ring thing..
Post by: Ivo on May 26, 2010, 07:59:59 pm
umm, by same direction u mean full turns?
im sorry...just never got this split ring thing..
Motor turns in one direction, one turn is one revolution. Just keeps turing one direction, alright?
Post by: Ivo on May 26, 2010, 08:00:30 pm
So Boyle's Law is that if temperature is constant, then when volume decreases, pressure increases?
This question hasn't been answered yet. please somebody
Post by: diva_sparkles on May 26, 2010, 08:01:28 pm
This question hasn't been answered yet. please somebodyyes!
Post by: 6394 on May 26, 2010, 08:01:34 pm
the cloth always remains damp because it is dipped in water on both sidethe energy required for the molecules to evaporate is obtained from the milk
the energy required for the molecules to evaporate is obtained from the milk
hope this helps
aisa kab hota hai
new to me ;)
Post by: NightHawkerr on May 26, 2010, 08:02:28 pm
One more question.
In past papers, where they ask us to draw resultant forces using parallelogram method, how exactly do we find the mag and direction of resultant force? Like in M/J 2009 Q 4ai)
???
Post by: Adzel on May 26, 2010, 08:02:48 pm
umm, but arent split rings there to change direction of I so that coil can take full-turns?
Nope those are called slip rings...Dont get mixed up!
Post by: thenewkid™ on May 26, 2010, 08:03:24 pm
Are You Sure??yes
objects tht hv internal energy are like a hot water bottle
Post by: Ivo on May 26, 2010, 08:03:56 pm
yes!
Where?
Post by: Ghost Of Highbury on May 26, 2010, 08:04:00 pm
the energy required for the molecules to evaporate is obtained from the milk
aisa kab hota hai
new to me ;)
The milk stays cool, because the water molecules in the damp cloth use the heat energy from the SUN to evaporate.
Post by: Ghost Of Highbury on May 26, 2010, 08:05:50 pm
oh okay thanks.
One more question.
In past papers, where they ask us to draw resultant forces using parallelogram method, how exactly do we find the mag and direction of resultant force? Like in M/J 2009 Q 4ai)
???
draw the parallelogram using the scale. The direction is the diagonal of the parallelogram, and the magnitude is its length(use the scale to convert it into Newtons)
draw the scale diagram as shown
measure the length of the diagonal and calculate the force accordingly
measure the angle
shud be
-> 5500N
--> 30o
attached
Post by: 8T on May 26, 2010, 08:06:06 pm
Where?So Boyle's Law is that if temperature is constant, then when volume decreases, pressure increases?
If u can answer it ..its is the one (:
Post by: Vin on May 26, 2010, 08:06:18 pm
The volume of a fixed mass of gas id directly proportional to its absolute temperature if the pressure is kept constant
V/T = K
Pressure Law
The pressure of a fixed mass of gas is directly propotional to its absolute temperature if the volume is kept constant
p/T = K
Boyle's Law
For a fixed mass of gas at constant tmeperature
pV = K
combining the laws
p1V1 p2V2
------ = -----
T1 T2
Post by: 8T on May 26, 2010, 08:06:37 pm
yesThanks.
objects tht hv internal energy are like a hot water bottle
Post by: rhea on May 26, 2010, 08:07:11 pm
Nope those are called slip rings...Dont get mixed up!
okay just one thing~
could you write a two-line use of split ring and slip ring..
incase it comes...
Post by: Adzel on May 26, 2010, 08:08:19 pm
Slip Rings -----> (http://sciencecity.oupchina.com.hk/npaw/student/glossary/img/slip_rings.jpg)<----- AC Generator
Split Rings -----> (http://electricalandelectronics.org/wp-content/uploads/2008/09/split-ring-commutator.gif) <----- DC Motor
Post by: diva_sparkles on May 26, 2010, 08:08:48 pm
Where?
wht do u mean?? ???
Post by: Shazizzzle on May 26, 2010, 08:09:25 pm
Because, in many of the past papers, we do not covert the temp. from deg. C to deg. K. Do we have to?
Some books say the only correct answer is obtained using K.
But, isn't that just the same thing? :S
i.e K = 273 + C
Post by: 8T on May 26, 2010, 08:10:07 pm
Charles' LawYou should be called Mr helpful xD
The volume of a fixed mass of gas id directly proportional to its absolute temperature if the pressure is kept constant
V/T = K
Pressure Law
The pressure of a fixed mass of gas is directly propotional to its absolute temperature if the volume is kept constant
p/T = K
Boyle's Law
You should have someone calling you MR HELPFUL xD
Thanks Vin for helping us all (:
For a fixed mass of gas at constant tmeperature
pV = K
combining the laws
p1V1 p2V2
------ = -----
T1 T2
Post by: diva_sparkles on May 26, 2010, 08:11:17 pm
Umm, is it necessary to use the absolute temperature, i.e Kelvin, when using the gas laws?
Because, in many of the past papers, we do not covert the temp. from deg. C to deg. K. Do we have to?
Some books say the only correct answer is obtained using K.
But, isn't that just the same thing? :S
i.e K = 273 + C
actualy in pastpapers u hd 2 do tht !!
Post by: Ivo on May 26, 2010, 08:11:46 pm
This is same paper, w09.
Post by: Ghost Of Highbury on May 26, 2010, 08:12:21 pm
OK, super hard question for Q10) If someone can guide me through how to work out b) onwards, that would be most helpful.
year, session? paper link?
Post by: mdwael on May 26, 2010, 08:12:54 pm
Post by: Ivo on May 26, 2010, 08:14:26 pm
year, session? paper link?
Sorry, here it is: http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_31.pdf
I don't understand how it is worked out.
Post by: 33oomar on May 26, 2010, 08:15:48 pm
PLEASE
Post by: Vin on May 26, 2010, 08:16:59 pm
Please please please can someone draw me the answer for the missing connections its question 9a in oct nov 2006 paper 3 physics (i) part how to I draw it?
Post by: Ghost Of Highbury on May 26, 2010, 08:19:27 pm
Sorry, here it is: http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_31.pdf
I don't understand how it is worked out.
10ai) Step up transformer obviously.
aii) Less current, less electrical energy lost, less heat energy given out
b) P = V*I, I = 55k/22k = 2.5
c) Rate of loss formula, P = I^2R = 2.5^2*3 = 18.75
d) The overall voltage reduced from 22K Volts due to the resistance of the wire, till it reaches the receiving end.
I know this is confusing sh*t, it had appeared in my paper! nov 09! V = 2.5*3 = 7.5
from wiki "For example, an electric space heater may very well have a resistance of ten ohms, and the wires which supply it may have a resistance of 0.2 ohms, about 2% of the total circuit resistance. This means that 2% of the supplied voltage is actually being lost by the wire itself."
e) 22000 - 7.5 -7.5 = 21985 (2 times 7.5 because there are two wires, each voltage dorp = 7.5)
Post by: Naruto123 on May 26, 2010, 08:20:34 pm
Post by: Vin on May 26, 2010, 08:22:38 pm
guys i need help in q8 May / JUne 2007 Paper 3 Part B
PLEASE
b) i)
P =I V
I = P/V
=36/1
=3A
ii) V = IR
R = V/I
=12/3
= 4 ohm
iii) 1/R = 1/R1 + 1/R
1/R = 1/4 + 1/4
1/R = 2/4 = 1/2
so, R = inverse of 1/2 = 2 ohm
iv) E = P t
= 36 * 30
=1080 J
Post by: Malak on May 26, 2010, 08:23:06 pm
Q11 part c nd so on the rest
thx
Post by: Adzel on May 26, 2010, 08:23:21 pm
guys i need help in q8 May / JUne 2007 Paper 3 Part B
PLEASE
Post by: mdwael on May 26, 2010, 08:23:31 pm
Post by: Vin on May 26, 2010, 08:23:43 pm
GUYZ do we have to change da temperature to kelvin or not ??? thx
yes while using the formula ..
p1V1 p2V2
------ = -----
T1 T2
Post by: Adzel on May 26, 2010, 08:26:22 pm
yes while using the formula ..
p1V1 p2V2
------ = -----
T1 T2
only this one???
Post by: Weaam on May 26, 2010, 08:26:35 pm
Please and thank you!
Post by: 33oomar on May 26, 2010, 08:27:06 pm
b) i)Oh thanks a lot dude ......... r u takin' paper 3 tomorrow
P =I V
I = P/V
=36/1
=3A
ii) V = IR
R = V/I
=12/3
= 4 ohm
iii) 1/R = 1/R1 + 1/R
1/R = 1/4 + 1/4
1/R = 2/4 = 1/2
so, R = inverse of 1/2 = 2 ohm
iv) E = P t
= 36 * 30
=1080 J
Post by: Ashe on May 26, 2010, 08:27:40 pm
And another question, i saw this in a past paper but couldnt find it again =S
When someone is driving in a car, and the car suddenly crashes. What's the energy change of the driver?
I know its from kinetic, but into what?
Post by: eastrimx on May 26, 2010, 08:27:56 pm
http://www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Nov/0625_w08_ms_3.pdf
Post by: dodi23 on May 26, 2010, 08:29:12 pm
I don't really understand why we use a relay in circuits. When they ask why a relay is used in a circuit? what's the full answer to that?
And another question, i saw this in a past paper but couldnt find it again =S
When someone is driving in a car, and the car suddenly crashes. What's the energy change of the driver?
I know its from kinetic, but into what?
into sound, heat nd potential energy :P
Post by: Adzel on May 26, 2010, 08:29:43 pm
Can anyone please please tell me the answer and draw the diagram of Q4 b in o/n 08 second varient?
Please and thank you!
(http://www.freeimagehosting.net/uploads/78aed3dc88.gif)
Rondom Jerky Motion
Post by: Ghost Of Highbury on May 26, 2010, 08:30:38 pm
THANK YOU :D
@master math - Variant one says its micrometer.
Post by: Shazizzzle on May 26, 2010, 08:32:56 pm
Post by: Adzel on May 26, 2010, 08:33:22 pm
I don't really understand why we use a relay in circuits. When they ask why a relay is used in a circuit? what's the full answer to that?
Small current swiches on large current....
Post by: The Golden Girl =D on May 26, 2010, 08:34:18 pm
are you confusing yourself with mechanical waves and light rays ??
VIN , i don't think u got what i meant ::) but anyways i can manage to understand it ;)
gd luck in ur french and Physics tomorrw ;).............gosh i luuuuuuuuuuuuv physics :-*....pray for me ,people :D
Post by: Weaam on May 26, 2010, 08:36:24 pm
Dude, thats part a, i need part b!(http://www.freeimagehosting.net/uploads/78aed3dc88.gif)Rondom Jerky Motion[/cente
but thanks..
Post by: 8T on May 26, 2010, 08:37:17 pm
GUYZ do we have to change da temperature to kelvin or not ??? thxyes we do.
Post by: Weaam on May 26, 2010, 08:37:37 pm
Thanks!
Post by: Ghost Of Highbury on May 26, 2010, 08:38:57 pm
Also can i get the answer to o/n 08 Q5 c(i) second varient!
Thanks!
Please provide the links next time you ask a doubt, thank you :D
ill answer this one..
Post by: Malak on May 26, 2010, 08:40:32 pm
Q11 part c n onwards..
thx
Post by: Vin on May 26, 2010, 08:43:20 pm
http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_31.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_31.pdf)
Q11 part c nd so on the rest
thxhttp://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_31.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_31.pdf)
Q11 part c n onwards..
thx
11 a) A- NOT gate B- AND
b) dark and cold = low light and low temp
Output of A = High
Output of B = Low
ii) dark and warm = low light and high temp.
Output of A = High
Output of B = High
iii) bright and warm = high light and hig temp.
Output of A = Low
Output of B = Low
c) i) Here the relay can be used to increase the current because the output of B is low .. Relay connects two circuits has its own power supply this supply is given as the output of the relay .. the output of B is enough to magnetize the iron in the relay which closes the contacts and supplies outout current (hope u know the structure of a relay so u'll get what im talking about .. in this question u dont have to answer this much ..)
ii) its b) ii) because its the only B output that is high
iii) In a fridge .. it has a closed environment and this type of circuit works in a compact/dark environment
Post by: Ghost Of Highbury on May 26, 2010, 08:44:05 pm
Please provide the links next time you ask a doubt, thank you :D
ill answer this one..
3 minuts = 180s
energy = 40*180 = 7200J
change in temp = 5.9
250g = 0.25Kg
E = m*c*t
7200/0.25*5.9 = 4881J/kgK
Post by: Adzel on May 26, 2010, 08:44:21 pm
http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_31.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_31.pdf)
Q11 part c n onwards..
thx
Why don't you check the Mark Scheme :-\
Post by: Weaam on May 26, 2010, 08:44:28 pm
Smaller gaps between ice...Dude, i think u got the wrong question! :-X
Post by: Shazizzzle on May 26, 2010, 08:44:38 pm
Post by: Ghost Of Highbury on May 26, 2010, 08:46:13 pm
Dude, i think u got the wrong question! :-X
Answered
Post by: Adzel on May 26, 2010, 08:46:31 pm
Dude, i think u got the wrong question! :-X
Sorry...I got to sleep cant concentrate.
Post by: Ghost Of Highbury on May 26, 2010, 08:47:51 pm
If you're not a 'Physics Doubt', you don't belong here. :P
hahaha!!
Post by: Weaam on May 26, 2010, 08:48:38 pm
3 minuts = 180sThaaanks a gajillion!
energy = 40*180 = 7200J
change in temp = 5.9
250g = 0.25Kg
E = m*c*t
7200/0.25*5.9 = 4881J/kgK
Could u also do from the same year Q4 part b?
Sorry for the trouble :-[
Post by: Adzel on May 26, 2010, 08:49:11 pm
If you're not a 'Physics Doubt', you don't belong here. :P
Im not a 'Physics Doubt', Im a Physics student :P
Post by: Adzel on May 26, 2010, 08:50:53 pm
GOOD LUCK TO ALL INSHAALLAH
Post by: 8T on May 26, 2010, 08:52:12 pm
Thaaanks a gajillion!Weaan Dnt yew have the ms...?
Could u also do from the same year Q4 part b?
Sorry for the trouble :-[
There..
air molecules hit dust particles in all directions/move it in all directions B1
just as likely to be up as down
Post by: Ghost Of Highbury on May 26, 2010, 08:54:03 pm
Thaaanks a gajillion!
Could u also do from the same year Q4 part b?
Sorry for the trouble :-[
The large number of air particles constantly collide with the dust particles in all directions which keeps most of them away from the ground
PS : however, as the ms says, its an equal probability that the dust particles will collide and fall, we ignore the ambiguity here.
Post by: Weaam on May 26, 2010, 08:54:53 pm
Weaan Dnt yew have the ms...?That kinda doesnt make sense "8T", thats why im asking!
There..
air molecules hit dust particles in all directions/move it in all directions B1
just as likely to be up as down
Plus i wanna know how the diagram is supposed to look like!
I have a feeling im gunna screw up physics so baad tmr!
Post by: Ashe on May 26, 2010, 08:55:17 pm
Small current swiches on large current....
thanks :) is that all? is there any like... safety reason? or smthn?
Post by: Weaam on May 26, 2010, 08:56:02 pm
The large number of air particles constantly collide with the dust particles in all directions which keeps most of them away from the groundUmm ... how is the diagram supposed to look like..?
PS : however, as the ms says, its an equal probability that the dust particles will collide and fall, we ignore the ambiguity here.
Post by: 6394 on May 26, 2010, 08:56:34 pm
gud lk 2 u ppl
[/b][/color][/size]
Post by: Helium on May 26, 2010, 08:57:32 pm
Why don't you check the Mark Scheme :-\
marking scheme sometimes just gives answer,
some people want to know why or how ???
Post by: Ghost Of Highbury on May 26, 2010, 08:58:06 pm
Umm ... how is the diagram supposed to look like..?
They haven't asked for the diagram in that subpart. Its not required, and drawing the huge no. of air particles colliding with dust particles is insane, just imagine that there is a huge no. of collisions going on which keeps the dust from falling down..
Post by: eastrimx on May 26, 2010, 09:01:16 pm
http://www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Nov/0625_w08_ms_3.pdf
Post by: Vin on May 26, 2010, 09:01:55 pm
marking scheme sometimes just gives answer,
some people want to know why or how ???
https://studentforums.biz/index.php/topic,6468.msg228261.html#msg228261
Post by: Weaam on May 26, 2010, 09:02:08 pm
They haven't asked for the diagram in that subpart. Its not required, and drawing the huge no. of air particles colliding with dust particles is insane, just imagine that there is a huge no. of collisions going on which keeps the dust from falling down..Actually it says, explain why the dust particles have not fallen to the floor. you may DRAW A LABELLED DIAGRAM to help your explanation...
I wonder what kind of diagram are we meant to draw and label here..
Post by: Weaam on May 26, 2010, 09:05:33 pm
O/N 08 Q8 part C second varient.
thaaaaank yoou!
Post by: Ghost Of Highbury on May 26, 2010, 09:06:55 pm
Good luck to y'all !! Hope you do well!
Sorry if its early to leave , but i have to go, 1:30 am here!!
@weaam = Attached. Green - Air, Black = Dust. Imagine all those collisions taking place. They simply cant fall down
Post by: Weaam on May 26, 2010, 09:09:54 pm
okay, im off guyz. 1:30 am ! ::)Im not even gunna try and draw that but thanks anywaays :D
Good luck to y'all !! Hope you do well!
Sorry if its early to leave , but i have to go, 1:30 am here!!
@weaam = Attached. Green - Air, Black = Dust. Imagine all those collisions taking place. They simply cant fall down
and goood luck!
Post by: Shazizzzle on May 26, 2010, 09:15:01 pm
What is meant by an electromotive force of 12V
O/N 08 Q8 part C second varient.
thaaaaank yoou!
The electromotive force of any battery is the amount of energy in joules provided to each coloumb (C) of charge, as it passes through the circuit.
So, the electromotive force of 12 V would mean,
the battery provides 12 J of energy to each coloumb (C) of charge as it passes through the circuit.
Post by: Helium on May 26, 2010, 09:17:50 pm
What is meant by an electromotive force of 12V
O/N 08 Q8 part C second varient.
thaaaaank yoou!
A cell (or battery) pushes electrons round a circuit.
It is a kind of electron pump.Different cells can exert different electrical pressures.
This electrical pressure is called electromotive force or e.m.f and it is measured in volts(V).
Extracted From (Physics for you).
;)
hope u understand
Post by: Weaam on May 26, 2010, 09:25:05 pm
The electromotive force of any battery is the amount of energy in joules provided to each coloumb (C) of charge, as it passes through the circuit.Thaaaaanks ssoo muuch!
So, the electromotive force of 12 V would mean,
the battery provides 12 J of energy to each coloumb (C) of charge as it passes through the circuit.
That was great help! ;)
Post by: Weaam on May 26, 2010, 09:26:00 pm
A cell (or battery) pushes electrons round a circuit.Its not reaally clear, but i kinda got it, thanks anyway! ;D
It is a kind of electron pump.Different cells can exert different electrical pressures.
This electrical pressure is called electromotive force or e.m.f and it is measured in volts(V).
Extracted From (Physics for you).
;)
hope u understand
Post by: Shazizzzle on May 26, 2010, 09:36:45 pm
When experimenting latent heat of fusion, the mass taken into consideration is the mass of the MELTED ICE i.e THE WATER FORMED, right?
And, when experimenting latent heat of vaporisation, the mass taken into consideration is the MASS OF THE STEAM FORMED, in other words, (final mass of beaker + water after experiment) - (initial mass of beaker + water before experiment), right? ???
Post by: red_911 on May 26, 2010, 09:49:21 pm
Post by: blackberry on May 26, 2010, 09:52:42 pm
how can we reduce power loss in relation to resistance?? decrease or increase?
and wat r de methods for changing resistance in relation to length,thickness,area,temp etc of wire?
Post by: Baladya on May 26, 2010, 09:54:25 pm
Can u plzz help, m totally stuck at this question and need to understand it fully cuz if i dont then m *** up tommorow :S
10)c)d)e)
first at C) how can we get Energy when we dont have time?
Then i get confused by the repeating stuff in the other questions
plz explain in a simple way cuz m confused :S
Thankssss :)
Post by: Baladya on May 26, 2010, 09:55:56 pm
PLZZZZZ HELP!!!!!!!!!!!!!!
how can we reduce power loss in relation to resistance?? decrease or increase?
and wat r de methods for changing resistance in relation to length,thickness,area,temp etc of wire?
Decrease
And what do u mean?? just get a thinner and thicker wire (if thats ur question). But there is no method in doing that 0.o
Post by: red_911 on May 26, 2010, 09:56:15 pm
Okay, a few more things.yeah u r right
When experimenting latent heat of fusion, the mass taken into consideration is the mass of the MELTED ICE i.e THE WATER FORMED, right?
And, when experimenting latent heat of vaporisation, the mass taken into consideration is the MASS OF THE STEAM FORMED, in other words, (final mass of beaker + water after experiment) - (initial mass of beaker + water before experiment), right? ???
Post by: blackberry on May 26, 2010, 10:00:10 pm
Decrease
And what do u mean?? just get a thinner and thicker wire (if thats ur question). But there is no method in doing that 0.o
like increasing the length of the wire increases resistance so what does increasin thickness of wire do?
Post by: diva_sparkles on May 26, 2010, 10:01:54 pm
like increasing the length of the wire increases resistance so what does increasin thickness of wire do?
decreases resistance n 4 temp it depends on da material eg semiconductors n metals
Post by: Syed Kazim on May 26, 2010, 10:02:49 pm
like increasing the length of the wire increases resistance so what does increasin thickness of wire do?
An increase in the length of a wire will
An increase in the diameter of a wire will decrease the resistance.
Post by: Malak on May 26, 2010, 10:03:24 pm
http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_31.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_31.pdf)
Can u plzz help, m totally stuck at this question and need to understand it fully cuz if i dont then m *** up tommorow :S
10)c)d)e)
first at C) how can we get Energy when we dont have time?
Then i get confused by the repeating stuff in the other questions
plz explain in a simple way cuz m confused :S
Thankssss :)
For c use this formula p=I^2 * r
d) The simple voltage formula that is V= IR
You jst hav to calculate the voltage drop by the resistor
e) There r 2 resistor so for one resistor the voltage drop is 7.5...Multiply by it 2 and subtract from the 22000
Post by: Baladya on May 26, 2010, 10:05:00 pm
http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_31.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_31.pdf)
Can u plzz help, m totally stuck at this question and need to understand it fully cuz if i dont then m *** up tommorow :S
10)c)d)e)
first at C) how can we get Energy when we dont have time?
Then i get confused by the repeating stuff in the other questions
plz explain in a simple way cuz m confused :S
Thankssss :)
cmon plzzz help ::)
Post by: Baladya on May 26, 2010, 10:06:02 pm
For c use this formula p=I^2 * r
ya okay, but thats for power, but they said energy??
Post by: blackberry on May 26, 2010, 10:06:36 pm
i kan sleep in peace noww!!!
Post by: Vin on May 26, 2010, 10:07:20 pm
http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_31.pdf (http://www.freeexampapers.us/IGCSE/Physics/CIE/2009%20Nov/0625_w09_qp_31.pdf)
Can u plzz help, m totally stuck at this question and need to understand it fully cuz if i dont then m *** up tommorow :S
10)c)d)e)
first at C) how can we get Energy when we dont have time?
Then i get confused by the repeating stuff in the other questions
plz explain in a simple way cuz m confused :S
Thankssss :)
u got afternoon right ?? thn i;ll do this tmw (for me). . im off to sleep ;)
like ang3l said use
H= I^2R
H is loss of heat energy ;)
Post by: diva_sparkles on May 26, 2010, 10:08:01 pm
cmon plzzz help ::)rate of loss of energy is the definition of power so thts how u do it!!!
Post by: Helium on May 26, 2010, 10:08:32 pm
hey can anyone explain me question 9(C) (2) ? ??? 0625/31/M/J/08
You can use fleming left hand rule to find the movement of the flexible wire.
-Point first finger in the direction of the magnetic field (from n to s)
-rotate your hand about that your finger until your second finger points in the direction of the Current.
then your thumb points in the direction of the movement of wire
Post by: Malak on May 26, 2010, 10:08:39 pm
ya okay, but thats for power, but they said energy??
Energy loss = I^2 R
thats how it is in my text book :P
Post by: Baladya on May 26, 2010, 10:09:23 pm
u got afternoon right ?? thn i;ll do this tmw (for me). . im off to sleep ;)
like ang3l said use
H= I^2R
H is loss of heat energy ;)
k thx all :P Vin plz stay alive for tommorow :D xD jk :P but plz help tommorow :P
Post by: Syed Kazim on May 26, 2010, 10:09:41 pm
ya okay, but thats for power, but they said energy??
Yes, same thing.
Post by: diva_sparkles on May 26, 2010, 10:10:08 pm
An increase in the length of a wire will decrease the resistance.sory 2 say but an increase in length increases resistance
An increase in the diameter of a wire will also decrease the resistance.
Post by: Syed Kazim on May 26, 2010, 10:10:25 pm
thanks syed, baladya and diva!!!!!!!!
i kan sleep in peace noww!!!
You're welcome. :)
Post by: NightHawkerr on May 26, 2010, 10:10:46 pm
Post by: Malak on May 26, 2010, 10:11:40 pm
sory 2 say but an increase in length increases resistancecorrect :D
Post by: Syed Kazim on May 26, 2010, 10:12:36 pm
sory 2 say but an increase in length increases resistance
Oops. Sorry, I'll edit that. :-[
Done.
Post by: diva_sparkles on May 26, 2010, 10:13:49 pm
Can somebody tell me what to study for the CRO for tomorrow's exam? I mean I know how to label and stuff, but then they get too complicated! HELP! ???
can u ask frm a specific pastpaper tht will be easier 2 explain?
Post by: Vin on May 26, 2010, 10:13:57 pm
k thx all :P Vin plz stay alive for tommorow :D xD jk :P but plz help tommorow :P
haha LOL .. i wont die without helping u :P
Post by: NightHawkerr on May 26, 2010, 10:15:19 pm
Post by: Baladya on May 26, 2010, 10:16:20 pm
Can somebody tell me what to study for the CRO for tomorrow's exam? I mean I know how to label and stuff, but then they get too complicated! HELP! ???
Cathode is heated and shoots electrons at high speed (and energy). It is the thing on the left. Then the anode atracts the electron and makes the electron pass through a gap in it. Then u've got the y-plates which move the electron up and down by + and -plates .(postitive attracts electron, negative deflects it. X-plates same thing but left and right. Then there is a Fluorescent screen which gives light when the electron hit it. A time-based circuit is connected to X-plates to move the dot (the dot shown on the screen) left to right at a constant speeed and then returns it very quickly to the start.
Post by: Syed Kazim on May 26, 2010, 10:17:13 pm
Using a CRO (http://astarmathsandphysics.com/gcse_physics_notes/gcse_physics_notes_using_a_cathode_ray_oscilloscope%20-%20cro.html)
Post by: Baladya on May 26, 2010, 10:17:46 pm
Post by: NightHawkerr on May 26, 2010, 10:18:01 pm
Cathode is heated and shoots electrons at high speed (and energy). It is the thing on the left. Then the anode atracts the electron and makes the electron pass through a gap in it. Then u've got the y-plates which move the electron up and down by + and -plates .(postitive attracts electron, negative deflects it. X-plates same thing but left and right. Then there is a Fluorescent screen which gives light when the electron hit it. A time-based circuit is connected to X-plates to move the dot (the dot shown on the screen) left to right at a constant speeed and then returns it very quickly to the start.
hm, quite confusing, but thanks so much! :)
Post by: Malak on May 26, 2010, 10:18:56 pm
Post by: Baladya on May 26, 2010, 10:19:15 pm
a pic to help u :P
http://www.circuitstoday.com/wp-content/uploads/2009/09/CRO-Block-Diagram.jpg (http://www.circuitstoday.com/wp-content/uploads/2009/09/CRO-Block-Diagram.jpg)
Post by: diva_sparkles on May 26, 2010, 10:19:29 pm
A voltmeter ( i think it was a voltmeter. dont remember exactly :P but has to do with volts :P) is attached to the y-plates
yup thts correct! :)
Post by: Syed Kazim on May 26, 2010, 10:22:24 pm
Anyone ??
(http://www.gcse.com/radio/images/penetrate.gif)
ALPHA: stopped by paper
BETA: goes through paper, stopped by thin metal (aluminium)
GAMMA: goes through paper and metal sheet. Stopped by thick lead or concrete.
Credit: Took it from gcse.com
EDIT: If the image is too small, click here (http://www.gcse.com/radio/images/penetrate.gif).
EDIT 2: In the exam you will have to draw a source on one side of the aluminium sheet and a count-meter on the other.
Post by: red_911 on May 26, 2010, 10:26:28 pm
Anyone ??which year is it ?
Post by: diva_sparkles on May 26, 2010, 10:27:39 pm
which year is it ?
i think it's solved
Post by: Baladya on May 26, 2010, 10:27:50 pm
Post by: Vin on May 26, 2010, 10:28:06 pm
Post by: Baladya on May 26, 2010, 10:29:22 pm
Post by: pglasg74 on May 26, 2010, 10:29:45 pm
http://www.freeexampapers.us/IGCSE/Physics/CIE/2007%20Jun/0625_s07_qp_3.pdf
Post by: blackberry on May 26, 2010, 10:33:28 pm
me textbuk says dat high voltage reduces power loss which means that resistance is also high so current is low!!!
so....which one is it??? i am sooo confused!!!
Post by: pglasg74 on May 26, 2010, 10:34:53 pm
someone please tell me why number 9 its anticlockwise.. if i used FLH, my index points right,
Post by: 6394 on May 26, 2010, 10:35:13 pm
something like this .. pls. excuse the handwriting ;)u still on lol
;) ;) ;) ;)
Post by: red_911 on May 26, 2010, 10:35:45 pm
something like this .. pls. excuse the handwriting ;)
lool @ the handwriting ;D
Post by: the_grim_reaper on May 26, 2010, 10:36:37 pm
Post by: pglasg74 on May 26, 2010, 10:38:03 pm
someone please tell me why number 9 its anticlockwise.. if i used FLH, my index points right, and my middle finger points towards me cse of the current (right?) so my thumb is up.. which means its clockwise.. what am i doing wrong? :(
Post by: Baladya on May 26, 2010, 10:38:08 pm
use P=VI ... when there is a higher Voltage there HAS to be a lower current. THE POWER IS THE SAME, its not changed. so when one is increased, the other decreases.
The more the current, the more there is heat loss. so we want a high voltage, which will cuz the current to be less and so less heat lost. but the same power will be given.
Post by: Baladya on May 26, 2010, 10:39:36 pm
Guys just one thing. Do we need to know how bistable circuits work for tomorrow? And what about a bridge rectifier?? Especially the example in June 09(If it has been answered, just mention the page number) . All I get is that it ends in a short-circuit :D. Smoked paper 1 and p 6 was good too but I'm scared about this one :'(....
I didnt study the bistable circuits cuz simply its SO FREAKIN CONFUSING and evrytime i try to understand it, i cant :S
Post by: 6394 on May 26, 2010, 10:40:10 pm
I used to do ur mistake... forget about resistance...lol hlpd me as wel Thanks
use P=VI ... when there is a higher Voltage there HAS to be a lower current. THE POWER IS THE SAME, its not changed. so when one is increased, the other decreases.
The more the current, the more there is heat loss. so we want a high voltage, which will cuz the current to be less and so less heat lost. but the same power will be given.
:P;)
Post by: diva_sparkles on May 26, 2010, 10:41:54 pm
I didnt study the bistable circuits cuz simply its SO FREAKIN CONFUSING and evrytime i try to understand it, i cant :S
same here!!!!!!lol
Post by: blackberry on May 26, 2010, 10:42:50 pm
I used to do ur mistake... forget about resistance...
use P=VI ... when there is a higher Voltage there HAS to be a lower current. THE POWER IS THE SAME, its not changed. so when one is increased, the other decreases.
The more the current, the more there is heat loss. so we want a high voltage, which will cuz the current to be less and so less heat lost. but the same power will be given.
Nice!!!
Post by: Ivo on May 26, 2010, 10:44:07 pm
1) d) ii) - how to work out average speed?
2) d) - why include 200g mass as well?
5) c) - why 16.3-2.1, I don't get it.
8) d) i) - why series and not parallel?
9) a) ???
Sorry for the flooding of qu.
Post by: Baladya on May 26, 2010, 10:45:31 pm
same here!!!!!!lol
I understand the system, but when it comes to the 'latch'... i dont understand sh*t :P I was absent when teacher explained it, told her to explain it to me, she told me not my problem 0.0 -.- Tried to understand myself... well how can i understand anything in the Collin's f**ked up book
Post by: soulreapr_ninja on May 26, 2010, 10:47:04 pm
i found paper 1 and paper 6 tough, hope the threshold is low :( n hope tomorows 1 is easy :(
Post by: diva_sparkles on May 26, 2010, 10:49:08 pm
I understand the system, but when it comes to the 'latch'... i dont understand sh*t :P I was absent when teacher explained it, told her to explain it to me, she told me not my problem 0.0 -.- Tried to understand myself... well how can i understand anything in the Collin's f**ked up book
actualy i found it better in collin's book thn da tom dunkcan 1 !! its way more confusin there!!
Post by: blackberry on May 26, 2010, 10:50:47 pm
blooodyyy shizzz!!!
so.....convex is real, inverted, and small?
concave is virtual, upright and small?? ??? ???
how do you define principal focus and length?? ??? ???
Post by: Syed Kazim on May 26, 2010, 10:52:06 pm
Potential Dividers (https://studentforums.biz/index.php/topic,7791.msg205880.html#msg205895)
Fleming's Right and Left Hand Rules (https://studentforums.biz/index.php/topic,7791.msg205895.html#msg205880)
Rectification (https://studentforums.biz/index.php/topic,7791.msg205904.html#msg205904)
Transistors (https://studentforums.biz/index.php/topic,7791.msg206096.html#msg206096)
Post by: SoONa on May 26, 2010, 10:52:28 pm
can some1 explain wht a reed switch is and wht we use it for and wht im suppose to kno 4 2mrrw... ughh confusin me 4 some reason
thanks a million .. ;D
Post by: diva_sparkles on May 26, 2010, 10:52:39 pm
resistance is futile!!!!!
blooodyyy shizzz!!!
so.....convex is real, inverted, and small?
concave is virtual, upright and small?? ??? ???
how do you define principal focus and length?? ??? ???
no!!!!!!! ok concave nt required 4 ig but convex it is different 4 all positions!!!
Post by: Syed Kazim on May 26, 2010, 10:53:33 pm
Post by: 6394 on May 26, 2010, 10:54:37 pm
Just thought I post these links:i wnt thru dem dey wer vre hlpful!!!!
Potential Dividers (https://studentforums.biz/index.php/topic,7791.msg205880.html#msg205895)
Fleming's Right and Left Hand Rules (https://studentforums.biz/index.php/topic,7791.msg205895.html#msg205880)
Rectification (https://studentforums.biz/index.php/topic,7791.msg205904.html#msg205904)
Transistors (https://studentforums.biz/index.php/topic,7791.msg206096.html#msg206096)
Post by: blackberry on May 26, 2010, 10:55:40 pm
no!!!!!!! ok concave nt required 4 ig but convex it is different 4 all positions!!!
ya dats true.....but our teacher gave us like a general thang for convex!!
my buk suxxxxx!!!!! its gcse 1982 edition!!!!!
Post by: pglasg74 on May 26, 2010, 11:00:04 pm
Post by: Syed Kazim on May 26, 2010, 11:01:30 pm
Object between F and Optical Centre - Virtual, Upright and Larger than the object.
Object between F and 2F - Real, Inverted and Larger than the object.
Object at 2F - Real, Inverted, Same size as the object.
Object beyond 2F - Real, Inverted and Smaller than the object.
Post by: the_grim_reaper on May 26, 2010, 11:04:48 pm
Right a couple of questions from w08 (Link: http://www.freeexampapers.us/IGCSE/Physics/CIE/2008%20Nov/0625_w08_qp_03.pdf)
1) d) ii) - how to work out average speed?
2) d) - why include 200g mass as well?
5) c) - why 16.3-2.1, I don't get it.
8) d) i) - why series and not parallel?
9) a) ???
Sorry for the flooding of qu.
Ivo you can't always find the distance using the average. If it isn't available, use a different formula. Here, my teacher taught me a very good one which can be used. Its distance=(initial speed)xtime+ 0.5(mass)(final velocity)^2 (squaring on final velocity). Pluck in the values and you'll get the right answer.
In case of forces, if in equilibrium, sum of forces in one direction is equal to sum of forces in other direction. Here downward forces (due to weights) AND the disc have to be used (the disc will also be pulled by gravity). The poor pivot will have to balance all of em'
For 5 c, I've got no idea. Shazzizle gave an odd explanation on Page 137.
For 8, it's series. In parallel they'll light with full brightness (since each gets the mains voltage, current blah blah). In series it's normal brightness.
For 9, the easiest idea is to pump water higher. It's almost in every text book. No capacitors since they can't be charged with AC (Thanks VIN!!!!!!)
Post by: NidZ- Hero on May 26, 2010, 11:05:13 pm
Post by: blackberry on May 26, 2010, 11:07:19 pm
Post by: the_grim_reaper on May 26, 2010, 11:07:30 pm
I understand the system, but when it comes to the 'latch'... i dont understand sh*t :P I was absent when teacher explained it, told her to explain it to me, she told me not my problem 0.0 -.- Tried to understand myself... well how can i understand anything in the Collin's f**ked up book
My teacher never heard the name. I didn't know it till reading collins. By the way, anyone knows how a bridge rectifier works!!! I'm getting really nervous here :( :(
Post by: pglasg74 on May 26, 2010, 11:09:03 pm
Converging Lens
Object between F and Optical Centre - Virtual, Upright and Larger than the object.
Object between F and 2F - Real, Inverted and Larger than the object.
Object at 2F - Real, Inverted, Same size as the object.
Object beyond 2F - Real, Inverted and Smaller than the object.
can u please help me with my qs? i posted it on this page or the last page? please thanxx!
Post by: diva_sparkles on May 26, 2010, 11:10:19 pm
can any 1 plz explain de ticker timmer stuff for de acceleration
Ticker-tape = http://www.physicsphenomena.com/TickerTape.html
http://www.practicalphysics.org/go/Experiment_310.html
Post by: Syed Kazim on May 26, 2010, 11:11:14 pm
i wnt thru dem dey wer vre hlpful!!!!
Glad I could help.
Post by: NidZ- Hero on May 26, 2010, 11:13:52 pm
u mean ticker tape?? dats not in de portion!!
noo it is it came in 2008 o/n p3
Post by: blackberry on May 26, 2010, 11:22:55 pm
noo it is it came in 2008 o/n p3
firstly its not in de syllabus!!!(i jus checked)!!
secondly o/n papers are harder nd kinda moe extensive than the m/j ones we do cuz if u see sum questions you wont understand it so well(im talking generallly)!!
thirdly o/n is mostly for those hoo do igcse outside of skool!!
see? 8)
Post by: Syed Kazim on May 26, 2010, 11:25:10 pm
can someone help and attach a drawing of 8a please :(
http://www.freeexampapers.us/IGCSE/Physics/CIE/2007%20Jun/0625_s07_qp_3.pdf
EDIT: I forgot to put the A in the ammeter. Please do label it in the exam.
Post by: Ivo on May 26, 2010, 11:26:40 pm
Ivo you can't always find the distance using the average. If it isn't available, use a different formula. Here, my teacher taught me a very good one which can be used. Its distance=(initial speed)xtime+ 0.5(mass)(final velocity)^2 (squaring on final velocity). Pluck in the values and you'll get the right answer.
In case of forces, if in equilibrium, sum of forces in one direction is equal to sum of forces in other direction. Here downward forces (due to weights) AND the disc have to be used (the disc will also be pulled by gravity). The poor pivot will have to balance all of em'
For 5 c, I've got no idea. Shazzizle gave an odd explanation on Page 137.
For 8, it's series. In parallel they'll light with full brightness (since each gets the mains voltage, current blah blah). In series it's normal brightness.
For 9, the easiest idea is to pump water higher. It's almost in every text book. No capacitors since they can't be charged with AC (Thanks VIN!!!!!!)
Thanks, you're amazing! By the way, for the pump water higher, how does it work, I still don't get that bit.
By the way, for the formula you're teacher told u is distance (s) = 0.5(u+v)t
Post by: pglasg74 on May 26, 2010, 11:30:30 pm
EDIT: I forgot to put the A in the ammeter. Please do label it in the exam.
omg thanks ur an angel.. i had 2 more qs though.. i think its 2007 but u know the question with the magnet and the wheel that turns? if not i plosted it a few pages ago.. umm ok tehy ask to find the driection of wheel turning, so my index pointed right, my current towards me and consequently my thumb pointed up.. which means clockwise idk how to get anticlockwise (the answer is anti)
and can u pls copy paste the image properties thankss
Post by: pglasg74 on May 26, 2010, 11:34:09 pm
EDIT: I forgot to put the A in the ammeter. Please do label it in the exam.
its number 9 in teh same paper.. 2007 mj.. thanks a loooot :)
and also http://www.freeexampapers.us/IGCSE/Physics/CIE/2005%20Nov/0625_w05_qp_3.pdf
q7 why is the eye to the right of the lens? can u tell me the image prop rules please thanks syed!
Post by: diva_sparkles on May 26, 2010, 11:35:15 pm
gud luck 4 physics exm!!! ;)
Post by: Syed Kazim on May 26, 2010, 11:38:57 pm
omg thanks ur an angel.. i had 2 more qs though.. i think its 2007 but u know the question with the magnet and the wheel that turns? if not i plosted it a few pages ago.. umm ok tehy ask to find the driection of wheel turning, so my index pointed right, my current towards me and consequently my thumb pointed up.. which means clockwise idk how to get anticlockwise (the answer is anti)
and can u pls copy paste the image properties thankss
I think this is what you meant by image properties:
Converging Lens
Object between F and Optical Centre - Virtual, Upright and Larger than the object.
Object between F and 2F - Real, Inverted and Larger than the object.
Object at 2F - Real, Inverted, Same size as the object.
Object beyond 2F - Real, Inverted and Smaller than the object.
About that question:
http://www.freeexampapers.us/IGCSE/Physics/CIE/2007%20Jun/0625_s07_qp_3.pdf
someone please tell me why number 9 its anticlockwise.. if i used FLH, my index points right,
Give me a few minutes please... let me figure it out.
Post by: 6394 on May 26, 2010, 11:41:42 pm
I think this is what you meant by image properties:where do u live
Converging Lens
Object between F and Optical Centre - Virtual, Upright and Larger than the object.
Object between F and 2F - Real, Inverted and Larger than the object.
Object at 2F - Real, Inverted, Same size as the object.
Object beyond 2F - Real, Inverted and Smaller than the object.
About that question:
Give me a few minutes please... let me figure it out.
r u givin xam in mornin??????????
Post by: Ivo on May 26, 2010, 11:43:34 pm
its number 9 in teh same paper.. 2007 mj.. thanks a loooot :)
and also http://www.freeexampapers.us/IGCSE/Physics/CIE/2005%20Nov/0625_w05_qp_3.pdf
q7 why is the eye to the right of the lens? can u tell me the image prop rules please thanks syed!
Here is my diagram in response to your question. Hope this helps :D
Post by: Syed Kazim on May 26, 2010, 11:46:55 pm
its number 9 in teh same paper.. 2007 mj.. thanks a loooot :)
and also http://www.freeexampapers.us/IGCSE/Physics/CIE/2005%20Nov/0625_w05_qp_3.pdf
q7 why is the eye to the right of the lens? can u tell me the image prop rules please thanks syed!
The distance of the object from the mirror (A in this case) must be equal to the distance of the mirror to the image (B in this case). Also, they must form in a straight line.
Post by: Syed Kazim on May 26, 2010, 11:48:16 pm
where do u live
r u givin xam in mornin??????????
Yes, I am. Its 2am here. :)
Post by: Syed Kazim on May 26, 2010, 11:49:25 pm
The distance of the object from the mirror (A in this case) must be equal to the distance of the mirror to the image (B in this case). Also, they must form in a straight line.
Oops. I thought you meant part (a). Anyway, just remember that in such questions the angle of incidence is equal to the angle of refraction.
Post by: 6394 on May 26, 2010, 11:51:16 pm
Yes, I am. Its 2am here. :)it 2.55 hre
=P
Post by: Syed Kazim on May 26, 2010, 11:52:49 pm
it 2.55 hre
=P
Lol... we're all working hard. When we get the A*s, we'll deserve it. :)
Post by: NidZ- Hero on May 26, 2010, 11:54:42 pm
Lol... we're all working hard. When we get the A*s, we'll deserve it. :)hey this thng ticker timer stuff is it dere if yes i wuld appreciate if u gud teach :)
Post by: Syed Kazim on May 26, 2010, 11:55:09 pm
I think this is what you meant by image properties:
Converging Lens
Object between F and Optical Centre - Virtual, Upright and Larger than the object.
Object between F and 2F - Real, Inverted and Larger than the object.
Object at 2F - Real, Inverted, Same size as the object.
Object beyond 2F - Real, Inverted and Smaller than the object.
About that question:
Give me a few minutes please... let me figure it out.
In the diagram, when the magnetic field lines are drawn, they will go from the left of the page to the right, thus pushing the wheel in the same direction, i.e. anti-clockwise.
Post by: 6394 on May 26, 2010, 11:55:53 pm
Lol... we're all working hard. When we get the A*s, we'll deserve it. :)yup InshAAllah
Post by: Syed Kazim on May 26, 2010, 11:56:46 pm
hey this thng ticker timer stuff is it dere if yes i wuld appreciate if u gud teach :)
Let me check the syllabus... I don't think it's there though.
Post by: the_grim_reaper on May 26, 2010, 11:58:56 pm
Thanks, you're amazing! By the way, for the pump water higher, how does it work, I still don't get that bit.
By the way, for the formula you're teacher told u is distance (s) = 0.5(u+v)t
Ivo the formula I wrote oh sh*t sorry it's distance=ut+.5at^2 (a is acceleration. Sorry for using mass! VERY VERY VERY VERY SORRY!!!) U see that's why I don't like to answer questions even if I know the answers. I'm afraid I might tell something wrong and it'll screw the guy I'm trying to help :D.
Anyway, you see some hydroelectric stations have a pumped storage feature. See demand varies at different times and seasons bla bla bla. So when demand is less and u're producing more energy, you can use it to pump the water that goes out of the dam back up to a higher-level reservoir. My book claims that it's easier to do this than to reduce the output of the generator (who wants to stop running water :D)..
So at peak times, the water will flow out again from the high level reservoir and the pe it has is converted to electrical energy. You can get 3-quarters of the electrical energy that was used to pump it back up in the first place.. (this answer is correct so it can be relied upon :D)...
Post by: Syed Kazim on May 27, 2010, 12:00:29 am
Let me check the syllabus... I don't think it's there though.
The words 'ticker', 'timer' and 'ticker-timer' do not appear anywhere in the syllabus.
Post by: 6394 on May 27, 2010, 12:00:41 am
higher staedy spd-stays same thru out but the space By the way dots is more dan abv
acceleration-distan btwn dot in creases ....... . . . . . . . .
deceleration -. . . . . . . . . ..........
hope it hlps
:P :P
Post by: the_grim_reaper on May 27, 2010, 12:01:03 am
it 2.55 hre
=P
2 am in Riyadh :D. Guys I'm gona say it again PLEASE CAN ANYONE TELL ME HOW A BRIDGE RECTIFIER WORKS!!!!!!!
Post by: Ivo on May 27, 2010, 12:03:33 am
10ai) Step up transformer obviously.
aii) Less current, less electrical energy lost, less heat energy given out
b) P = V*I, I = 55k/22k = 2.5
c) Rate of loss formula, P = I^2R = 2.5^2*3 = 18.75
d) The overall voltage reduced from 22K Volts due to the resistance of the wire, till it reaches the receiving end.
I know this is confusing sh*t, it had appeared in my paper! nov 09! V = 2.5*3 = 7.5
from wiki "For example, an electric space heater may very well have a resistance of ten ohms, and the wires which supply it may have a resistance of 0.2 ohms, about 2% of the total circuit resistance. This means that 2% of the supplied voltage is actually being lost by the wire itself."
e) 22000 - 7.5 -7.5 = 21985 (2 times 7.5 because there are two wires, each voltage dorp = 7.5)
This is from W09, it's a nightmare. What's voltage drop?
Post by: Ivo on May 27, 2010, 12:06:15 am
Ivo the formula I wrote oh sh*t sorry it's distance=ut+.5at^2 (a is acceleration. Sorry for using mass! VERY VERY VERY VERY SORRY!!!) U see that's why I don't like to answer questions even if I know the answers. I'm afraid I might tell something wrong and it'll screw the guy I'm trying to help :D.
Anyway, you see some hydroelectric stations have a pumped storage feature. See demand varies at different times and seasons bla bla bla. So when demand is less and u're producing more energy, you can use it to pump the water that goes out of the dam back up to a higher-level reservoir. My book claims that it's easier to do this than to reduce the output of the generator (who wants to stop running water :D)..
So at peak times, the water will flow out again from the high level reservoir and the pe it has is converted to electrical energy. You can get 3-quarters of the electrical energy that was used to pump it back up in the first place.. (this answer is correct so it can be relied upon :D)...
Thanks man, great explanation. I'll rep you!
Post by: the_grim_reaper on May 27, 2010, 12:06:25 am
This is from W09, it's a nightmare. What's voltage drop?
Drop in voltage :D. If power is being lost than it's bound to have an effect!!!
Post by: Syed Kazim on May 27, 2010, 12:06:38 am
2 am in Riyadh :D. Guys I'm gona say it again PLEASE CAN ANYONE TELL ME HOW A BRIDGE RECTIFIER WORKS!!!!!!!
Bridge rectifiers
There are several ways of connecting diodes to make a rectifier to convert AC to DC. The bridge rectifier is one of them and it is available in special packages containing the four diodes required. Bridge rectifiers are rated by their maximum current and maximum reverse voltage. They have four leads or terminals: the two DC outputs are labelled + and -, the two AC inputs are labelled .
The diagram shows the operation of a bridge rectifier as it converts AC to DC. Notice how alternate pairs of diodes conduct.
EDIT: Attached another diagram.
Post by: 6394 on May 27, 2010, 12:06:46 am
2 am in Riyadh :D. Guys I'm gona say it again PLEASE CAN ANYONE TELL ME HOW A BRIDGE RECTIFIER WORKS!!!!!!!bridge wave rectifier is a full wave rectifier
https://studentforums.biz/index.php/topic,7791.0.html
Post by: Ivo on May 27, 2010, 12:09:06 am
Drop in voltage :D. If power is being lost than it's bound to have an effect!!!
The 22,000V thing, is it equally supplied to each of the lines. Also, what's defined as p.d. betweeen the pair of wires, I don't get taht
Post by: 6394 on May 27, 2010, 12:10:10 am
Bridge rectifiersrem parallel sides of rhombus or square blah same diode
There are several ways of connecting diodes to make a rectifier to convert AC to DC. The bridge rectifier is one of them and it is available in special packages containing the four diodes required. Bridge rectifiers are rated by their maximum current and maximum reverse voltage. They have four leads or terminals: the two DC outputs are labelled + and -, the two AC inputs are labelled .
The diagram shows the operation of a bridge rectifier as it converts AC to DC. Notice how alternate pairs of diodes conduct.
EDIT: Attached another diagram.
opp 2 terminals cnnct 2 i/p
"""""""""""""""""""""""""""""""o/p
Post by: the_grim_reaper on May 27, 2010, 12:18:50 am
Bridge rectifiers
There are several ways of connecting diodes to make a rectifier to convert AC to DC. The bridge rectifier is one of them and it is available in special packages containing the four diodes required. Bridge rectifiers are rated by their maximum current and maximum reverse voltage. They have four leads or terminals: the two DC outputs are labelled + and -, the two AC inputs are labelled .
The diagram shows the operation of a bridge rectifier as it converts AC to DC. Notice how alternate pairs of diodes conduct.
EDIT: Attached another diagram.
THank you so much!!!!! Man I'm very grateful! +rep!!!
Post by: the_grim_reaper on May 27, 2010, 12:20:00 am
rem parallel sides of rhombus or square blah same diode
opp 2 terminals cnnct 2 i/p
"""""""""""""""""""""""""""""""o/p
Thank you too!!!! :D I wanted to rep you too but its asking me to wait for 118 minutes :D.
Post by: Syed Kazim on May 27, 2010, 12:22:31 am
THank you so much!!!!! Man I'm very grateful! +rep!!!
Glad I could help. Thanks... ;D
Post by: 6394 on May 27, 2010, 12:42:54 am
lol thx
Thank you too!!!! :D I wanted to rep you too but its asking me to wait for 118 minutes :D.
=PP
ny1 stil awake ???
wen planin 2 slp
Post by: Syed Kazim on May 27, 2010, 12:48:19 am
lol thx
=PP
ny1 stil awake ???
wen planin 2 slp
Present. I want to finish off for Geography P2 before going to sleep. Should be asleep by 4am my time (2:50 currently).
Post by: 6394 on May 27, 2010, 12:51:09 am
Present. I want to finish off for Geography P2 before going to sleep. Should be asleep by 4am my time (2:50 currently).3.50 hre
will slp at 5 or 5.30
gud lck 4 geogr.!!!
;) ;) ;)
Post by: Syed Kazim on May 27, 2010, 12:51:52 am
3.50 hre
will slp at 5 or 5.30
gud lck 4 geogr.!!!
;) ;) ;)
Thanks...!
Post by: 6394 on May 27, 2010, 12:52:59 am
3.50 hreall credits goes to my frnd
will slp at 5 or 5.30
gud lck 4 geogr.!!!
;) ;) ;)
lol she is callin me aftr vry 30-45 mins on mob. to ask som doubts n i bcum fresh =pPPPP
Post by: Syed Kazim on May 27, 2010, 12:54:31 am
all credits goes to my frnd
lol she is callin me aftr vry 30-45 mins on mob. to ask som doubts n i bcum fresh =pPPPP
Lol... same here. Friends always remember their doubts late at night... lucky for them we're awake.
Post by: NidZ- Hero on May 27, 2010, 12:57:34 am
Post by: Syed Kazim on May 27, 2010, 01:06:50 am
can any 1 help me 2002 m/j w Q2cii
BC+DC=17.5m/s
Post by: 6394 on May 27, 2010, 01:14:35 am
so circuit wont switch on
Post by: NidZ- Hero on May 27, 2010, 01:15:14 am
BC+DC=17.5m/sbut y i dunt understand
Post by: Ivo on May 27, 2010, 01:17:32 am
The 22,000V thing, is it equally supplied to each of the lines. Also, what's defined as p.d. betweeen the pair of wires, I don't get taht
Please can someone answer my doubt. Many thanks
Post by: 6394 on May 27, 2010, 01:22:18 am
Please can someone answer my doubt. Many thanksis dat from 09 o n
because i hve de sam doubt
e part
Post by: Ivo on May 27, 2010, 01:24:02 am
is dat from 09 o n
because i hve de sam doubt
e part
yes, w09. What's the 22,000V about?
Post by: 6394 on May 27, 2010, 01:50:05 am
??
Post by: 6394 on May 27, 2010, 01:56:03 am
dint sleep at nyt =P
pray 4 me
Talk to you later
Take care
:) :) :) :) :) ;) ;) ;) ;) ;) :D :D :D :D :D ::) ::) ::) ::) :P :P :P
Post by: J.Darren on May 27, 2010, 04:29:38 am
is dat from 09 o nFrom part b we have found the current in one of the transmission lines to be 2.5 A using the equation P = IV. From part c we have found the power loss to be 18.75W using the equation P = I^2 R. From part d we have found the voltage drop to be 7.5 V using the equation V = IR. The voltage drop here is referring to the voltage at thje receiving end of the transmission lines, a pair of transmission lines will have a voltage drop of 7.5 * 2 = 15 V, the answer would then be 22000 - 15 = 21985 V.
because i hve de sam doubt
e part
Post by: jellybeans on May 27, 2010, 05:05:15 am
WHEN DO WE USE SINR / SINI?
from MEDIUM TO AIR?
Post by: Girlie45 on May 27, 2010, 05:11:59 am
Post by: CatAly$t on May 27, 2010, 07:11:11 am
HI@@@ URGENT.
WHEN DO WE USE SINR / SINI?
from MEDIUM TO AIR?
sin i/sin r
to find the refractive index of a substance.....
Post by: CatAly$t on May 27, 2010, 07:19:17 am
When is acceleration increasing in a speed/time graph ??? ???
when the gradient is positive...
Post by: Vin on May 27, 2010, 08:01:27 am
Hey sup guys hows everything going ?? :D
Post by: lalala on May 27, 2010, 08:02:32 am
Post by: Vin on May 27, 2010, 08:12:52 am
guys..i think its been 24 hours :P can i discuss something abt phy p1?
Let the MODERATORS agree to it .. :)
then discuss it here .. ;)
https://studentforums.biz/index.php/topic,7273.2700.html
Post by: Weaam on May 27, 2010, 08:23:49 am
No more physicsss! yesss! ;D
Post by: CatAly$t on May 27, 2010, 08:25:13 am
Post by: Helium on May 27, 2010, 08:30:04 am
can anybody tell me about commutators?
A commutator makes sure the current in the brush contacts always flow in the same way,
like in a simple d.c. dynamo
Post by: J.Darren on May 27, 2010, 08:35:21 am
Back from the exaam! ;DNo more physics !! P3 is easier compared to P1 I would say :D
No more physicsss! yesss! ;D
Post by: Helium on May 27, 2010, 08:43:46 am
No more physics !! P3 is easier compared to P1 I would say :D
You saying that makes me confindent, Thanks ;D
Post by: Weaam on May 27, 2010, 08:47:47 am
No more physics !! P3 is easier compared to P1 I would say :DIt wasnt :O
To me, physics all of it was really BAD!
I screwed up BIG!
Post by: The Golden Girl =D on May 27, 2010, 08:50:33 am
It wasnt :O
To me, physics all of it was really BAD!
I screwed up BIG!
let's not say anything ....cuz ome say it was easy some so no it was hard ...... Helium be confident ....
i really hope everyone here does well ....Allah ma3aku ;)
Post by: guMnam on May 27, 2010, 08:50:51 am
Post by: Mathewness on May 27, 2010, 08:58:32 am
Post by: Dana on May 27, 2010, 09:03:58 am
Nope those are called slip rings...Dont get mixed up!Nono! Split rings make sure he motor keep turning. Slip rings are in a generator
Post by: Dana on May 27, 2010, 09:09:39 am
LDR :Thaanks so much, but the transistor thing is confusing, when the base current increases does the collector current increase or decrease?? ??? do you mind explaining that part please?
As Light intensity decreases on LDR, The resistance across it increases, thus V input increases. When V input is more than 0.6 V, the transistor is switched ON, and thus the lamp/ alarm etc. turns ON.
Post by: Dana on May 27, 2010, 09:12:15 am
Pleaseee answerr! Thanks in advance
Post by: CatAly$t on May 27, 2010, 09:13:59 am
Post by: Dana on May 27, 2010, 09:18:16 am
who can answer this question??? 8)To calculate the current you need either power/ voltage and/or resistance. They might've given you that information previously. If you know the power and the voltage is given (12) then use the power formula. If they gave you the resistance then use the second formula
P=IV or V=IR
Post by: Ghost Of Highbury on May 27, 2010, 09:24:10 am
And you guys there are 2 wires going through a paper, both of them are now connected to a battery source. The current is going down both. Why and in what direction does the flexible wire move? its so confusingg ??? MJ 08 qs 9) c)
Pleaseee answerr! Thanks in advance
https://studentforums.biz/index.php/topic,7291.msg196914.html#msg196914
Post by: Dana on May 27, 2010, 09:28:54 am
https://studentforums.biz/index.php/topic,7291.msg196914.html#msg196914Aaah thansk so much I finally get it :D
Post by: Baladya on May 27, 2010, 09:44:35 am
Post by: Shazizzzle on May 27, 2010, 09:45:49 am
who can answer this question(part c)??8)
Wait, wasn't this question DELETED? XD
Post by: Shazizzzle on May 27, 2010, 09:52:26 am
I hope we won't be disappointed.
Post by: Baladya on May 27, 2010, 09:53:37 am
Post by: Shazizzzle on May 27, 2010, 10:00:24 am
Hey can anyone plz explain whats ionizing particles, which ones are, and how is it used :) Thanks ;)
In radioactivity, the three types of radiation, alpha particles, beta particles and gamma particles have different ionising powers.
alpha particles have a very high ionising power. i.e It forms an ion, by gain of electrons very quick. In only very less air distance is it readily ionised and stablized.
Gamma have a very low ionising power, however have a high penetration power and so are used to detect clogs or blockages in circulation around the body. As they can penetrate across the skin, to a detector, where they accumulate i.e where the count is largest and is not seeming to move, it proves the vessels there are blocked.
Post by: Baladya on May 27, 2010, 10:02:21 am
Post by: DANDUNAH on May 27, 2010, 10:05:16 am
Post by: Weaam on May 27, 2010, 10:10:54 am
it was baddd like hell....urghhhhAgreed!
Post by: CatAly$t on May 27, 2010, 10:13:09 am
To calculate the current you need either power/ voltage and/or resistance. They might've given you that information previously. If you know the power and the voltage is given (12) then use the power formula. If they gave you the resistance then use the second formula
P=IV or V=IR
lol...just tricking u...i got confused with this question...i look at the ms...it says,question deleted... 8) 8)
they made a mistake...silly CIE...
Post by: Mathewness on May 27, 2010, 10:13:51 am
Paper 05 november. Can someone help me out here? Question 2c; i know the direction of the force is downwards but how do we find the magnitude of force?
Anyone know? ???
Post by: Bleasthzzz on May 27, 2010, 10:14:52 am
• The density of an object only changes when the substance is heated or cooled.
• Use a sinker if the object’s density is less than that of the liquid that it’s placed in.
• When there is no air resistance the acceleration of any object is constant.
• Easier to lift an object on the moon because gravity is less on the moon and there is no air resistance.
• Resultant Force.
• Gravitational, electrostatic and magnetic forces can be applied from a distance, other than that you have to be in contact with the object to apply a force.
• A force applied on an object can cause a change in speed, direction or shape.
• Acceleration is a vector.
• When an object moves in a circle it is accelerating and at constant speed at the same time; because the direction is changing but the speed is constant.
• Centripetal force is caused by tension in the string (ball on a string), gravity (satellite in space), friction between the tires and the road (a car on the road).
• For an object to be in equilibrium the resultant force has equal zero (forces up = forces down) and the resultant moment has to equal zero (clockwise moment = anticlockwise moment).
• For the stability of an object it has to have a wide base and a low center of mass.
• To find the center of mass draw two points A and B, hang the object from each hole so that it can swing freely. Tie a weight to each point then draw the vertical line, the center of gravity is where the lines intersect.
• When a car is going up a hill K.E. = Same, G.P.E = Increases, Chemical Energy (petrol) = Decreases and the total energy stays the same as energy is not lost, created or destroyed.
• Internal energy = Thermal energy.
• Fission = Power stations, Large molecules ? Small molecules.
• Fusion = Sun, Small molecules ? Large molecules.
• The mass lost is converted into heat energy.
• In barometers the space at the top is a vacuum, because air would prevent the mercury from rising.
• The width of the barometer does not affect the height of mercury.
• Water manometers are more accurate to measure gas pressure.
• To get the total pressure, remember to add the atmospheric pressure.
• The gas pressure can be converted from mm of Hg to Pa by using P = ? g h, but remember to use the total pressure.
?
Thermal Physics
• The pressure is the same on all the walls of the containers as the molecules move in a random motion.
• ? Temperature = ? K.E. + Molecules hit the walls harder and more often.
• Brownian motion: The tiny, fast-moving air molecules, which are in a constant random motion, are hitting the larger smoke particles from all directions.
• Evaporation: The wind blows away any fast-moving molecules that have escaped from the water surface leaving more room for the next molecules to escape.
• ? Surface area = The number of surface particles ? so more molecules escape.
• Evaporation occurs at surface of liquid: no bubbles.
• Boiling occurs within liquid: bubbles appear.
• We feel cold because the molecules with the most kinetic energy escape from the surface and so the average kinetic energy of the remaining molecules ? and the temperature ?.
• Thermal expansion: molecules gain kinetic energy and force each other further apart.
• ? Volume = less area so the particles hit the walls harder and more often.
• Mercury is used to measure high temperature.
• Alcohol is used to measure low temperatures.
• The capillary tube of a thermometer is narrow so a small change in temperature results in a large change in volume of the liquid.
• Thermocouples have a low specific heat capacity this means they can measure rapidly changing temperatures and they don’t take much heat away from the object they are measuring the temperature of.
• During melting or boiling the temperature stops rising because extra energy is needed, which is taken from the heat source, to overcome the strong forces of attraction which are holding the molecules together. This energy will not increase the speed of the molecules it will only break the bonds.
• In an experiment the value for the latent heat of fusion is too low as energy is taken in from the surroundings which melt the ice.
• In an experiment the latent heat of vaporisation is too high as energy is lost to the air from the heater therefore not all the energy is used for evaporating the water.
• The value for the latent heat of vaporisation is much higher than the value for fusion because a large amount of energy is needed to break the bonds between the molecules to move them far apart.
Waves, Light & Sound
• Waves transfer energy from one place to another.
• The larger the frequency and amplitude the greater the energy of the wave.
• When a wave gets refracted, its Speed ?, Wavelength ?, Frequency = Same.
• When a wave gets reflected, its Speed = Same, Wavelength = Same, Frequency = Same.
• When a wave gets diffracted, its Speed = Same, Wavelength = Same, Frequency = Same.
• Radio waves are easily diffracted because they have a large wavelength.
• In the spectrum of light all the colors have the same speed, but different wavelengths & frequencies.
• Objects that produce light are called luminous objects.
• When a light wave travels from a less dense material ? more dense material, the refractive index is more than 1.
• When a light wave travels from a more dense material ? less dense material, the refractive index is less than 1.
• A fish in a pond appears to be higher than it actually is because light refracts.
• The centre of a lens is called its optical centre, C.
• The line through C at right angles to the lens is called the principle axis.
• The fatter the lens, the stronger it is and the shorter its focal length.
• Parallel light, e.g. Sun, must be used to find the focal length of a lens.
• When the object is at 2F the image is at 2F, real, inverted and same size as the object.
• Dispersion of white light occurs because each fraction of white light has a different wavelength, so they are slowed down by different amounts.
• A ripple tank is used to represent transverse waves.
• A spring is used to represent longitudinal waves.
The speed of sound in:
Air 330 m/s
Water 1400 m/s
Wood 4000 m/s
• Sound waves consist of a train of compressions and rarefactions in the air.
• When a loudspeaker moves out the air is compressed, when it moves in the air is rarefied.
• Frequency = number of vibrations per second.
• The speed of sound increases as the particles move closer together.
• Gamma Rays, X-Rays, Ultra-Violet are Carcinogenic.
Wave Use
Gamma Rays Sterilize food &equipment, Treat Cancer
X-Rays Go through body to check for broken bones
Ultra-Violet Suntan, Make fluorescent materials glow
Light Allows you to see
Infrared Heating, Remote Control, Mobile phones, Night sight
Microwaves Send messages, Cook food
Radio & T.V. Send messages
Electricity & Magnetism
• Ferrous (magnetic) metals are Iron, Steel, Nickel & Cobalt.
• The true test for a magnet is that it repels another magnet.
• When a ferrous metal is magnetized the domains are turned so that they are lined up.
• Making Magnets: Stroking, Electrically (D.C.).
• Demagnetising a magnet: Heating, Hammering, Electrically (A.C.).
• Uses of permanent magnets: Compasses, Door catches.
• Uses of electromagnets: Scrap yards, Electric bell, Electric relay.
• Conductors have free moving electrons in them, insulators don’t.
• In electrostatic experiments metals cannot be used as they are good conductors of electricity and don’t stay charged.
• In ammeters and voltmeters Red terminal = Positive, Black terminal = Negative.
• When the resistors are connected in parallel the total resistance is always less than the smallest resistor.
• Advantages of parallel circuits: each appliance can be switched on and off independently, if on appliance “blows”, the rest is unaffected, appliances in parallel gain the full voltage of the battery (e.g. lamps are brighter).
• Voltmeters must have a high resistance so that the current doesn’t flow down the voltmeter; instead the current continues to flow around the circuit.
• In a voltage/current graph the gradient = resistance, therefore the resistance of the conductor is constant as the gradient is constant.
• Diode is a device which only allows voltage to flow one way.
• It’s used for changing A.C. ? D.C.
• Temperature ? = Resistance ?
• Voltage ? = Resistance ?
• Appliances that use a large current must have thick cables to avoid overheating.
• In a short circuit the wires become very hot and the battery quickly drains.
• Three pin plugs: Earth = Yellow/Green stripes, Live = Brown, Neutral = Blue.
• Electricity enters via the live wire and returns via the neutral.
• The earth wire protects the user from getting an electrical shock, it’s connected to the metal casing of the appliance.
• Fuses are connected to the live wire, so if the current is too high, the fuse melts before the current reaches the appliance. Switches are also connected to the live wire.
• Circuit breakers contain an electromagnet which, when the current exceeds the rated value of the circuit breaker, becomes powerful enough to pull a pair of contacts apart and break the circuit.
• Advantages of circuit breakers: Much faster than fuses, Can be reset by pressing a button.
• Reversing the current of a wire reverses the direction of the magnetic field.
• To make a magnetic field stronger: ? Current, ? Number of turns on the coil.
• Motors: When a wire carrying a current is placed at 90o between the poles of the magnet the wire experiences a force.
• Fleming’s left hand rule: Thumb = Direction of Movement, First Finger = Direction of Field, Second Finger = Direction of Current in a wire.
• The split ring reverses the current every half turn so the coil keeps turning the same way.
• To change the direction of spin: Change the polarity of the magnets, change the direction of the current.
• To make the motor spin faster: wind the coil around more times, ? the current through the coil, stronger magnets.
• Generators: When coil cuts a magnetic field a voltage (current) is induced.
• To increase the voltage (current) induced: Move the magnet faster, Use a stronger magnet, Put more turns on the coil.
• Maximum current is induced when the coil is at 90o to the magnetic field. When it’s parallel there’s no cutting, hence no current.
• When an alternating current is passed through the primary coil a changing magnetic field is set up in the soft iron core, which is cut by the secondary coil. Hence, an E.M.F. is induced in the secondary coil.
• The soft iron core helps to concentrate the magnetic field through the coils.
• A step-up transformer is used near power stations to increase the voltage and to decrease current so there’s no overheating and energy loss is reduced.
• Transformers don’t work with D.C. because the current is not changing so there’s no cutting.
• The soft iron core helps to concentrate the magnetic field through the coils.
• Thermionic Emission occurs when electrons at the surface of the cathode are given enough energy to escape.
• Y and X –Shift Knobs move the display vertically and horizontally.
• The fluorescent screen transfers Kinetic Energy ? Light Energy.
• Y-Gain Knob sets the scale for the C.R.O.
• Voltage (current) is connected to the Y-Plates.
• Time Base is connected to the X-Plates.
• When using a voltage divider we must connect up terminals A,B and C.
• As the slider moves towards B the voltage decreases, as it moves towards A the voltage increases.
• In Reed switches & relays all the contacts are in a glass tube.
• A Reed switch is operated by a magnet.
• A Reed relay is operated by a coil which produces a magnetic field.
• LDR: Light ?the resistance.
• Thermistor: ? Temperature = ?Resistance.
• Capacitors are used for storing charge, they are used in time delay circuits (e.g. burglar alarm).
• Advantages of a transistor: Fast, Cheap, Doesn’t wear out; because it has no moving parts.
• Logic gates are made from transistors.
Atomic Physics
• The mass of an electron is 1/1840 A.M.U.
• We can write the nucleon and proton numbers of an element in a shorthand form called nuclide notation.
• An atom is nearly empty space apart from a tiny, heavy (dense), positive nucleus.
• Background radiation varies slightly as the radioactivity is random.
Name Alpha (?) Beta (?) Gamma (?)
Nature & Source 2 neutrons + 2 protons
From Nucleus A fast moving electron
Neutron in nucleus splits up to produce an electron and a proton. Electromagnetic wave
Extra energy released from nucleus. Usually following ? or ? decays.
Charge +2 -1 0
Mass 4 A.M.U. 1/1840 A.M.U. 0
Speed 10% speed of light 50% speed of light Speed of light
Absorption Stopped by a piece of paper, few cm of air Stopped by a few mm of aluminium Reduced, but not stopped, by lead
Ability to ionise Strongly Weakly Very Weakly
Deflection in electric fields Small, towards negative Large, towards positive No deflection
Deflection in magnetic fields Small, same as wire Large, opposite direction of wire No deflection
Range in air About 6 cm of air One meter or more Very large
Detectors Photographic Film
Cloud Chamber
Thin window G-M tube
Spark Counter Photographic film
Cloud Chamber
G-M tube
Photographic Film
Cloud Chamber
G-M tube
• The spark counter: The Alpha source ionizes the air, the positive ions move towards the cathode and the negative ions move towards the anode, so a spark is produced. Only works with alpha as they are excellent in ionising.
• Geiger-Muller tube: Works the same way as the spark counter but can detect all types of radiation. Thin Mica window so alpha radiation can pass through; a large potential difference is needed so that there is an anode and a cathode to attract the charges. To differentiate between types of radiation detected use absorbers.
Safety Precautions:
• Keep all radioactive materials in sealed containers made of thick lead.
• Keep as far away from radioactive source as possible and use tongs.
• Waste radioactive products are either buried underground or under the sea.
• Keep exposure time as short as possible.
• Don’t eat or drink near a radioactive substance.
• Label radioactive sources with radioactive sign.
• Wear a radioactive badge: Hole to detect ?, Aluminium to detect ?, Lead to detect ?.
• Half life is not affected by temperature, pressure or chemical reactions.
Use Type Half-Life
Detect cracks in underground pipes ? – Gas Short
Measure thickness of paper ? Long, to keep activity constant
Sterilizing equipment in hospitals ? Short
Smoke Detectors ? Long, to keep activity constant and detectors will last longer
Smoke Detectors:
Alpha radiation ionizes the air, therefore a sensor detects radiation. Smoke reduces radiation and the sensor turns the alarm on.
Post by: Baladya on May 27, 2010, 10:16:43 am
Thanks for the tips Bleasthzz :D
Post by: CatAly$t on May 27, 2010, 10:49:09 am
Post by: Mathewness on May 27, 2010, 11:02:57 am
General Physics
• The density of an object only changes when the substance is heated or cooled.
• Use a sinker if the object’s density is less than that of the liquid that it’s placed in.
• When there is no air resistance the acceleration of any object is constant.
• Easier to lift an object on the moon because gravity is less on the moon and there is no air resistance.
• Resultant Force.
• Gravitational, electrostatic and magnetic forces can be applied from a distance, other than that you have to be in contact with the object to apply a force.
• A force applied on an object can cause a change in speed, direction or shape.
• Acceleration is a vector.
• When an object moves in a circle it is accelerating and at constant speed at the same time; because the direction is changing but the speed is constant.
• Centripetal force is caused by tension in the string (ball on a string), gravity (satellite in space), friction between the tires and the road (a car on the road).
• For an object to be in equilibrium the resultant force has equal zero (forces up = forces down) and the resultant moment has to equal zero (clockwise moment = anticlockwise moment).
• For the stability of an object it has to have a wide base and a low center of mass.
• To find the center of mass draw two points A and B, hang the object from each hole so that it can swing freely. Tie a weight to each point then draw the vertical line, the center of gravity is where the lines intersect.
• When a car is going up a hill K.E. = Same, G.P.E = Increases, Chemical Energy (petrol) = Decreases and the total energy stays the same as energy is not lost, created or destroyed.
• Internal energy = Thermal energy.
• Fission = Power stations, Large molecules ? Small molecules.
• Fusion = Sun, Small molecules ? Large molecules.
• The mass lost is converted into heat energy.
• In barometers the space at the top is a vacuum, because air would prevent the mercury from rising.
• The width of the barometer does not affect the height of mercury.
• Water manometers are more accurate to measure gas pressure.
• To get the total pressure, remember to add the atmospheric pressure.
• The gas pressure can be converted from mm of Hg to Pa by using P = ? g h, but remember to use the total pressure.
?
Thermal Physics
• The pressure is the same on all the walls of the containers as the molecules move in a random motion.
• ? Temperature = ? K.E. + Molecules hit the walls harder and more often.
• Brownian motion: The tiny, fast-moving air molecules, which are in a constant random motion, are hitting the larger smoke particles from all directions.
• Evaporation: The wind blows away any fast-moving molecules that have escaped from the water surface leaving more room for the next molecules to escape.
• ? Surface area = The number of surface particles ? so more molecules escape.
• Evaporation occurs at surface of liquid: no bubbles.
• Boiling occurs within liquid: bubbles appear.
• We feel cold because the molecules with the most kinetic energy escape from the surface and so the average kinetic energy of the remaining molecules ? and the temperature ?.
• Thermal expansion: molecules gain kinetic energy and force each other further apart.
• ? Volume = less area so the particles hit the walls harder and more often.
• Mercury is used to measure high temperature.
• Alcohol is used to measure low temperatures.
• The capillary tube of a thermometer is narrow so a small change in temperature results in a large change in volume of the liquid.
• Thermocouples have a low specific heat capacity this means they can measure rapidly changing temperatures and they don’t take much heat away from the object they are measuring the temperature of.
• During melting or boiling the temperature stops rising because extra energy is needed, which is taken from the heat source, to overcome the strong forces of attraction which are holding the molecules together. This energy will not increase the speed of the molecules it will only break the bonds.
• In an experiment the value for the latent heat of fusion is too low as energy is taken in from the surroundings which melt the ice.
• In an experiment the latent heat of vaporisation is too high as energy is lost to the air from the heater therefore not all the energy is used for evaporating the water.
• The value for the latent heat of vaporisation is much higher than the value for fusion because a large amount of energy is needed to break the bonds between the molecules to move them far apart.
Waves, Light & Sound
• Waves transfer energy from one place to another.
• The larger the frequency and amplitude the greater the energy of the wave.
• When a wave gets refracted, its Speed ?, Wavelength ?, Frequency = Same.
• When a wave gets reflected, its Speed = Same, Wavelength = Same, Frequency = Same.
• When a wave gets diffracted, its Speed = Same, Wavelength = Same, Frequency = Same.
• Radio waves are easily diffracted because they have a large wavelength.
• In the spectrum of light all the colors have the same speed, but different wavelengths & frequencies.
• Objects that produce light are called luminous objects.
• When a light wave travels from a less dense material ? more dense material, the refractive index is more than 1.
• When a light wave travels from a more dense material ? less dense material, the refractive index is less than 1.
• A fish in a pond appears to be higher than it actually is because light refracts.
• The centre of a lens is called its optical centre, C.
• The line through C at right angles to the lens is called the principle axis.
• The fatter the lens, the stronger it is and the shorter its focal length.
• Parallel light, e.g. Sun, must be used to find the focal length of a lens.
• When the object is at 2F the image is at 2F, real, inverted and same size as the object.
• Dispersion of white light occurs because each fraction of white light has a different wavelength, so they are slowed down by different amounts.
• A ripple tank is used to represent transverse waves.
• A spring is used to represent longitudinal waves.
The speed of sound in:
Air 330 m/s
Water 1400 m/s
Wood 4000 m/s
• Sound waves consist of a train of compressions and rarefactions in the air.
• When a loudspeaker moves out the air is compressed, when it moves in the air is rarefied.
• Frequency = number of vibrations per second.
• The speed of sound increases as the particles move closer together.
• Gamma Rays, X-Rays, Ultra-Violet are Carcinogenic.
Wave Use
Gamma Rays Sterilize food &equipment, Treat Cancer
X-Rays Go through body to check for broken bones
Ultra-Violet Suntan, Make fluorescent materials glow
Light Allows you to see
Infrared Heating, Remote Control, Mobile phones, Night sight
Microwaves Send messages, Cook food
Radio & T.V. Send messages
Electricity & Magnetism
• Ferrous (magnetic) metals are Iron, Steel, Nickel & Cobalt.
• The true test for a magnet is that it repels another magnet.
• When a ferrous metal is magnetized the domains are turned so that they are lined up.
• Making Magnets: Stroking, Electrically (D.C.).
• Demagnetising a magnet: Heating, Hammering, Electrically (A.C.).
• Uses of permanent magnets: Compasses, Door catches.
• Uses of electromagnets: Scrap yards, Electric bell, Electric relay.
• Conductors have free moving electrons in them, insulators don’t.
• In electrostatic experiments metals cannot be used as they are good conductors of electricity and don’t stay charged.
• In ammeters and voltmeters Red terminal = Positive, Black terminal = Negative.
• When the resistors are connected in parallel the total resistance is always less than the smallest resistor.
• Advantages of parallel circuits: each appliance can be switched on and off independently, if on appliance “blows”, the rest is unaffected, appliances in parallel gain the full voltage of the battery (e.g. lamps are brighter).
• Voltmeters must have a high resistance so that the current doesn’t flow down the voltmeter; instead the current continues to flow around the circuit.
• In a voltage/current graph the gradient = resistance, therefore the resistance of the conductor is constant as the gradient is constant.
• Diode is a device which only allows voltage to flow one way.
• It’s used for changing A.C. ? D.C.
• Temperature ? = Resistance ?
• Voltage ? = Resistance ?
• Appliances that use a large current must have thick cables to avoid overheating.
• In a short circuit the wires become very hot and the battery quickly drains.
• Three pin plugs: Earth = Yellow/Green stripes, Live = Brown, Neutral = Blue.
• Electricity enters via the live wire and returns via the neutral.
• The earth wire protects the user from getting an electrical shock, it’s connected to the metal casing of the appliance.
• Fuses are connected to the live wire, so if the current is too high, the fuse melts before the current reaches the appliance. Switches are also connected to the live wire.
• Circuit breakers contain an electromagnet which, when the current exceeds the rated value of the circuit breaker, becomes powerful enough to pull a pair of contacts apart and break the circuit.
• Advantages of circuit breakers: Much faster than fuses, Can be reset by pressing a button.
• Reversing the current of a wire reverses the direction of the magnetic field.
• To make a magnetic field stronger: ? Current, ? Number of turns on the coil.
• Motors: When a wire carrying a current is placed at 90o between the poles of the magnet the wire experiences a force.
• Fleming’s left hand rule: Thumb = Direction of Movement, First Finger = Direction of Field, Second Finger = Direction of Current in a wire.
• The split ring reverses the current every half turn so the coil keeps turning the same way.
• To change the direction of spin: Change the polarity of the magnets, change the direction of the current.
• To make the motor spin faster: wind the coil around more times, ? the current through the coil, stronger magnets.
• Generators: When coil cuts a magnetic field a voltage (current) is induced.
• To increase the voltage (current) induced: Move the magnet faster, Use a stronger magnet, Put more turns on the coil.
• Maximum current is induced when the coil is at 90o to the magnetic field. When it’s parallel there’s no cutting, hence no current.
• When an alternating current is passed through the primary coil a changing magnetic field is set up in the soft iron core, which is cut by the secondary coil. Hence, an E.M.F. is induced in the secondary coil.
• The soft iron core helps to concentrate the magnetic field through the coils.
• A step-up transformer is used near power stations to increase the voltage and to decrease current so there’s no overheating and energy loss is reduced.
• Transformers don’t work with D.C. because the current is not changing so there’s no cutting.
• The soft iron core helps to concentrate the magnetic field through the coils.
• Thermionic Emission occurs when electrons at the surface of the cathode are given enough energy to escape.
• Y and X –Shift Knobs move the display vertically and horizontally.
• The fluorescent screen transfers Kinetic Energy ? Light Energy.
• Y-Gain Knob sets the scale for the C.R.O.
• Voltage (current) is connected to the Y-Plates.
• Time Base is connected to the X-Plates.
• When using a voltage divider we must connect up terminals A,B and C.
• As the slider moves towards B the voltage decreases, as it moves towards A the voltage increases.
• In Reed switches & relays all the contacts are in a glass tube.
• A Reed switch is operated by a magnet.
• A Reed relay is operated by a coil which produces a magnetic field.
• LDR: Light ?the resistance.
• Thermistor: ? Temperature = ?Resistance.
• Capacitors are used for storing charge, they are used in time delay circuits (e.g. burglar alarm).
• Advantages of a transistor: Fast, Cheap, Doesn’t wear out; because it has no moving parts.
• Logic gates are made from transistors.
Atomic Physics
• The mass of an electron is 1/1840 A.M.U.
• We can write the nucleon and proton numbers of an element in a shorthand form called nuclide notation.
• An atom is nearly empty space apart from a tiny, heavy (dense), positive nucleus.
• Background radiation varies slightly as the radioactivity is random.
Name Alpha (?) Beta (?) Gamma (?)
Nature & Source 2 neutrons + 2 protons
From Nucleus A fast moving electron
Neutron in nucleus splits up to produce an electron and a proton. Electromagnetic wave
Extra energy released from nucleus. Usually following ? or ? decays.
Charge +2 -1 0
Mass 4 A.M.U. 1/1840 A.M.U. 0
Speed 10% speed of light 50% speed of light Speed of light
Absorption Stopped by a piece of paper, few cm of air Stopped by a few mm of aluminium Reduced, but not stopped, by lead
Ability to ionise Strongly Weakly Very Weakly
Deflection in electric fields Small, towards negative Large, towards positive No deflection
Deflection in magnetic fields Small, same as wire Large, opposite direction of wire No deflection
Range in air About 6 cm of air One meter or more Very large
Detectors Photographic Film
Cloud Chamber
Thin window G-M tube
Spark Counter Photographic film
Cloud Chamber
G-M tube
Photographic Film
Cloud Chamber
G-M tube
• The spark counter: The Alpha source ionizes the air, the positive ions move towards the cathode and the negative ions move towards the anode, so a spark is produced. Only works with alpha as they are excellent in ionising.
• Geiger-Muller tube: Works the same way as the spark counter but can detect all types of radiation. Thin Mica window so alpha radiation can pass through; a large potential difference is needed so that there is an anode and a cathode to attract the charges. To differentiate between types of radiation detected use absorbers.
Safety Precautions:
• Keep all radioactive materials in sealed containers made of thick lead.
• Keep as far away from radioactive source as possible and use tongs.
• Waste radioactive products are either buried underground or under the sea.
• Keep exposure time as short as possible.
• Don’t eat or drink near a radioactive substance.
• Label radioactive sources with radioactive sign.
• Wear a radioactive badge: Hole to detect ?, Aluminium to detect ?, Lead to detect ?.
• Half life is not affected by temperature, pressure or chemical reactions.
Use Type Half-Life
Detect cracks in underground pipes ? – Gas Short
Measure thickness of paper ? Long, to keep activity constant
Sterilizing equipment in hospitals ? Short
Smoke Detectors ? Long, to keep activity constant and detectors will last longer
Smoke Detectors:
Alpha radiation ionizes the air, therefore a sensor detects radiation. Smoke reduces radiation and the sensor turns the alarm on.
Woo thanks!
Post by: Baladya on May 27, 2010, 11:09:23 am
lol where is everyone ;D
Post by: Vin on May 27, 2010, 11:46:34 am
Hey can anyone plz explain whats ionizing particles, which ones are, and how is it used :) Thanks ;)
Gm tube works on the ionizing effects of any radiation ..
brackets are atoms
(+,-) ---------> ( + ) + -
(neutral atom) positive ion electron
Ok Alpha has the most ionizing effects .. then beta particles followed by Gamma ray ..
Post by: Syed Kazim on May 27, 2010, 03:40:44 pm
soreee 2 disturb kazim bt ans this : wen less temp , more res.less voltage n vic versa ryt--> for thermistor
so circuit wont switch on
Sorry I could not answer your question, I was studying Geography and after that forgot to check back here.
Post by: CatAly$t on May 27, 2010, 05:32:45 pm
everybody is enjoying now???
Post by: contraentry on May 27, 2010, 06:20:03 pm
where did everybody go??no post since 3 hours....
everybody is enjoying now???
Everybody must be studying / revising now.
People like me have 2 Exams tomorrow (business & economics) and some people have business, eco and travel.
I hope we get good marks!
Post by: Vin on May 27, 2010, 07:16:36 pm
And people like me are enjoying ;D
best of luck for BS and Eco ;)
Post by: 6394 on May 27, 2010, 07:28:12 pm
Sorry I could not answer your question, I was studying Geography and after that forgot to check back here.lol hey kazim
its k!!!!
sup ;)
hw ws ppr??? :) :) :)
Post by: Helium on May 29, 2010, 03:21:23 pm
But you'll be back one day.
Post by: 6394 on May 30, 2010, 09:49:29 am
I can see that everyone's totally done with physics. ;Dhehehaha
But you'll be back one day.
lol
:D :D :D :D
Post by: guMnam on May 31, 2010, 08:02:29 am
Post by: Vin on May 31, 2010, 08:37:29 pm
haha :D .. agreed! ;)
Post by: holtadit on June 02, 2010, 08:08:18 am
Time for it to drift into the abyss !! :P
GOODBYE !!!
Post by: astarmathsandphysics on June 03, 2010, 07:38:24 pm
Post by: elemis on June 03, 2010, 07:40:41 pm
bye bye
LOL ! Havent seen you around in some time.
Post by: astarmathsandphysics on June 03, 2010, 10:01:00 pm