Post by: Q80BOY on May 22, 2009, 06:13:00 pm
if u have any physics questions or doubts, post them here
Thanks
Post by: Bani on May 22, 2009, 09:34:32 pm
May you please help me with this: In Paper 3 Physics May/June 2008, Q No.6. Could you please attach the actual drawing of rays and image, please. Thank-You.Hey guys,
if u have any physics questions or doubts, post them here
Thanks
and Q7 too, please. Thank-you.
Post by: sweetsh on May 22, 2009, 09:35:41 pm
Post by: sanity_master on May 22, 2009, 09:56:55 pm
Okay.......
just to prove them wrong....its all working great as u can see.....ppl ask question and wait for answeres
Post by: sweetsh on May 22, 2009, 09:58:18 pm
Post by: sanity_master on May 22, 2009, 10:00:48 pm
Haha he editted his post immediately after my post. It was only quoting, no question.
hahahahaha......
i g2g now......cya l8r :D
Post by: Ghost Of Highbury on May 23, 2009, 10:36:11 am
plz find attached image
a.) image
b.) virtual, erect, magnified
Post by: Ghost Of Highbury on May 23, 2009, 10:37:54 am
i'm too stuck in the 7th question....
maybe if sum1 cud help out..
Post by: nasser1111 on May 23, 2009, 11:09:41 am
im currently in Grade 10
I just had some doubts in the lesson Energy, Work and Power
That lesson really makes me mad
If anyone has any notes or revision guides for this lesson
Or if someone can explain me in short all the formulas and definitions i need to know for this lesson
I know that this is quite annoying to ask such lengthy questions but some help for this would really be appreciated
E-Mail: silvershark_55@hotmail.com
Thanks to everyone in Advance and all the best in ur exams :)
Post by: godfather93 on May 23, 2009, 11:12:13 am
http://books.google.com/books?id=P1hL1EwElX4C&printsec=frontcover&dq=complete+physics#PPA7,M1
Post by: nasser1111 on May 23, 2009, 11:14:15 am
you might want to go to this site. It's a good book!
http://books.google.com/books?id=P1hL1EwElX4C&printsec=frontcover&dq=complete+physics#PPA7,M1
Thanks :D
Post by: forkasha on May 23, 2009, 11:54:59 am
Post by: Bani on May 23, 2009, 12:36:22 pm
heres ur answer bani...
plz find attached image
a.) image
b.) virtual, erect, magnified
Thank-you :)
Post by: godfather93 on May 23, 2009, 12:57:48 pm
Post by: godfather93 on May 23, 2009, 01:13:31 pm
This topic will be deleted after 1 hour.
Post by: SGVaibhav on May 23, 2009, 01:56:12 pm
STATES OF MATTER PLEASE!
Post by: Bani on May 23, 2009, 02:00:01 pm
i've got a really really very good powerpoint on electricity and energy. Will be putting it up shortly.
Thanks a lot,
May you (or anyone else) please help me with Q7a) May/June 2008, Physics, Paper 3. I would highly appreciate if you can attach the drawing...Pleaseee. Im really, really worried, as my Physics teacher was all unorganised this year and did not cover the portion in great detail.....though Im a good student :D and hope to get an A*, Inshallah.
Thanks in advance :)
Post by: SGVaibhav on May 23, 2009, 02:04:36 pm
plzz guys need help BADLY
i get confused when they ask to explain in terms of something
such as
Describe, in terms of particles, the process by which heat is transferred through the cylinder wall. [this terms thingy confuses me very much]
and i need detailed notes for states of matter
Post by: godfather93 on May 23, 2009, 02:07:52 pm
Post by: forkasha on May 23, 2009, 02:10:08 pm
Post by: godfather93 on May 23, 2009, 02:21:20 pm
Post by: Shogun on May 23, 2009, 04:32:17 pm
anyone has notes for CRO?
STATES OF MATTER PLEASE!
hey i dont have the notes by i can explain to u throuly
cathode ray oscillascope. has 6 parts.
the filament: it goes through thermionic emiision(where a substance is heated it releases electrons) this filament is heated and releases electorns with negative charge.
the anode grid: it has a positve charge. this controls the nrightness (ill tell u how later)
the cathode grid: it has a negative charge, this allows the beam of electron (the electrons emitted when tht filament was heated)
the y plates:hese have plates with (+) and (-) charge and are attached vertically to each other on the tube of the CRO. this helps the beam of electrons move up and down so the beam of electrons spread evenly (up and down) on the screen.
the x plate: these have plates with (+) and (-) charge and are attached horizontilly to each other on the tube of the CRO. these help the electrons move (left and right) as it hits the screen.
the screen: at the end of the CRO is the screen (made of fluroscent usually) when electorns hit this screen it glows.
without x plate and y plates u will see the beam of electrons hitting one point of the screen only (so only tht part glows) for eg:on TV (just an example) , if with out x plates and y plates, picture can only be seen as a spot of light (picture) on the screen. but with x and y plates the electrons are able to reach both (up and down) and (right and left) with the help of y plates and x plates respectively. (ill tell u how they work later))
how does the OCR work?
first the filament is heated, beams of electrons are emitted (this is callerd thermionic emission). they go throu the cathode. what does cathod do? Cathode are negatively charge (-) and so are the beam of electrons, so repulsion take place due to similar charges allowing some beams of electrons to "stay back". This control the brightness cuz "the more number of electrons hittin the screen, the brighter the pic comes on the screen". ok, then the beams pass through the anode. what does the anode do? Anode is positively charged (+) and the beam of electrons are oppesitely charged. this anode atracts the beam of electron giving the "boost" or "acceleration" and to travel in a straight line (beam). then it reaches the Y plates. as i told u the help the electrons move up and down . they are plates with voltages (charged with (+) and (-))). they are GIVEN WITH A.C VLTAGE because if it was D.C then the elctrons would only move up OR down depending on the position of the positively charged plate ( as beam of electron is negatively charged). u see, A.C current changes its direction so the plates change their charges, whic means (+) become (-) then later (-) becomes (+). so (+) charge changes its positon and so does the beam of electron which changes its direction of deflection. this helps the electrons to touch both up and down of the screen.
the X plate are same, except they help the electrons to move right and left they are also charged except tht they are aranged horizontally. they are time base. the work with time, how? by letting the voltage between these plates go 0 then after sometime go to a certain value. how tghis helps? as the voltage has acertain value thts not 0 the beam deflects to towards positively charged plate. then when after a certain time it the voltage goes 0 immediately. this all ows the beam of electrons to GO BACK its old path (which was before deflection at X PLATE), then vise versa. this helps the electrons go left and right on the screen.
U might ask what in x plate there is time base and in y plates are AC current? why cant the put AC on the xplates too? This is because i think tht the time base system helps beam to go in the REQUIRED or aprropriate horizontal path.
then finally the electrons reaches the screen in every direction (with the help of x and y plates) which causes the whole fluroscent screen to glow or lit.
any help needed or any confusion im all here m8....
i hope this helpd
Post by: SGVaibhav on May 23, 2009, 04:44:28 pm
before reading the file and post
would like to tell one thing
i found some notes about cro, will post over here (different kinda notes)
Post by: Shogun on May 23, 2009, 04:45:48 pm
anywayz post em here,wanna know more
Post by: MaNa on May 23, 2009, 04:51:52 pm
Hey guys,
if u have any physics questions or doubts, post them here
Thanks
I ne4ed to ask this question
May/june 05
Q 10bi)n ii)
is it Cathode ray ????thwy alomost ask it in every paper :-\
Post by: godfather93 on May 23, 2009, 04:54:49 pm
Post by: MaNa on May 23, 2009, 04:56:09 pm
it's a very similar arrangement to the cathode ray tube.can u explain n tell me
please :)
Post by: SGVaibhav on May 23, 2009, 04:59:33 pm
i have all the possiblites of spots appearing on screen
will post in night as i will be free that time
one confusion
there is AC voltage in x plates or what?
Post by: Shogun on May 23, 2009, 05:01:04 pm
Post by: nid404 on May 23, 2009, 05:04:35 pm
Post by: SGVaibhav on May 23, 2009, 05:11:24 pm
???
u are an all rounder i guess
Post by: nid404 on May 23, 2009, 05:15:40 pm
Post by: godfather93 on May 23, 2009, 05:16:54 pm
it's a very similar arrangement to the cathode ray tube.can u explain n tell me
please :)
here's a rough drawing of the thing
Post by: Bani on May 23, 2009, 05:32:42 pm
it's a very similar arrangement to the cathode ray tube.can u explain n tell me
please :)
here's a rough drawing of the thing
mana, for part ii), the readings that would need to be taken are: First, record the background radiation (without the source and absorber), then record the radiation count with the source (using the detector) and lastly, record the radiaiton count with source and absorber (using the detector).
P.S Did anyone try drawing for Q7a), May/June 2008, paper 3???
Post by: godfather93 on May 23, 2009, 05:34:34 pm
Post by: Bani on May 23, 2009, 05:40:16 pm
yes, very easy.
On Fig 7.1, aren't the wavefronts suppossed to reflect to the left?
Post by: godfather93 on May 23, 2009, 05:42:16 pm
Post by: Bani on May 23, 2009, 05:47:05 pm
the ray is supposed to be reflected to the right. the wave fronts are at 90o to the main big arrow that u draw.
Can you attach the drawing? Pleaseee? Like I said before, my teacher didn't really teach us the actual Physics :(
Post by: godfather93 on May 23, 2009, 05:49:11 pm
Post by: Bani on May 23, 2009, 05:58:17 pm
if i can draw it, sure. :)
hehe ok :) Thanks anyways :)
P.S Try your best ;D
Post by: godfather93 on May 23, 2009, 05:59:00 pm
Post by: qwert101 on May 23, 2009, 06:07:49 pm
whats the formula connecting the number of electrons, time, and charge?
it was on M/J 02
q 7c) i) and ii)
thanks alot, Just need to know the formula, I ve forgotten it! ???
Post by: astarmathsandphysics on May 23, 2009, 06:09:03 pm
hi people,
whats the formula connecting the number of electrons, time, and charge?
it was on M/J 02
q 7c) i) and ii)
thanks alot, Just need to know the formula, I ve forgotten it! ???
Q=net
Post by: Bani on May 23, 2009, 06:30:43 pm
here's the image!
Thank-you Thank-you Thank-you
+rep :)
Post by: godfather93 on May 23, 2009, 06:32:28 pm
Post by: aj ahmed07 on May 23, 2009, 06:52:48 pm
Post by: godfather93 on May 23, 2009, 06:54:43 pm
Post by: qwert101 on May 23, 2009, 07:18:29 pm
hi people,
whats the formula connecting the number of electrons, time, and charge?
it was on M/J 02
q 7c) i) and ii)
thanks alot, Just need to know the formula, I ve forgotten it! ???
Q=net
great! , thanks but what does e stand for , n is number of electrons, q is charge, t is time right?
Post by: godfather93 on May 23, 2009, 07:25:00 pm
Post by: MaNa on May 23, 2009, 07:28:16 pm
THANK YOU SOOOOOO MUCH :D:D:D:D:D :D ;Dit's a very similar arrangement to the cathode ray tube.can u explain n tell me
please :)
here's a rough drawing of the thing
mana, for part ii), the readings that would need to be taken are: First, record the background radiation (without the source and absorber), then record the radiation count with the source (using the detector) and lastly, record the radiaiton count with source and absorber (using the detector).
P.S Did anyone try drawing for Q7a), May/June 2008, paper 3???
Post by: MaNa on May 23, 2009, 07:28:56 pm
thankyou god father:Dit's a very similar arrangement to the cathode ray tube.can u explain n tell me
please :)
here's a rough drawing of the thing
ohh so when they ask this much labelling is enough?
Post by: godfather93 on May 23, 2009, 07:30:53 pm
Post by: MaNa on May 23, 2009, 07:33:35 pm
more than enough since it is only a 2 marks question (i think it's 2 marks, right)alright
but yab3 if they ask (irrelevent to markzs) this much labelling iss enough? bcuz i have three book but none of them have this method:S
ooh so could Cathode ray tube could be mention too
bcuz thats also to identify beta particle:S
By the way + rep for u:D
Post by: godfather93 on May 23, 2009, 07:39:09 pm
yes, this labelling is enough. there's nothing left to label anyways. you may put the whole setting inside a tube or not. Depends.
it's not exactly a CRT. (we r measuring the percentage of beta particles passing through the aluminium sheet)
Post by: MaNa on May 23, 2009, 07:40:13 pm
Post by: esso on May 23, 2009, 09:15:44 pm
nov 2008
paper 3
ques.1)d
Post by: X Abdulrahman X on May 23, 2009, 09:23:22 pm
could some one help in this question
nov 2008
paper 3
ques.1)d
V=0.5 x 1.2
V=0.6m/s
Post by: X Abdulrahman X on May 23, 2009, 09:24:24 pm
Post by: esso on May 23, 2009, 09:50:56 pm
Post by: MaNa on May 23, 2009, 10:07:36 pm
Post by: Bani on May 23, 2009, 10:20:21 pm
2nd variant paper not first
The lubricated truck would accelerate. (Since it is lubricated, when the slope is returned to its original position, the forces will be unbalanced<as there is almost no friction now>, and the truck will accelerate).
I hope that helped. :)
Post by: Bani on May 23, 2009, 10:36:59 pm
When do we use cathode ray tube?
Cathode Ray Tube is used in terms of light (Total Internal Reflection); every time the ray of light within totally internally reflects and therefore the light ray remains within the tube. An example of its use is in the transfer of TV signals.
For Electricity, its the Cathode Ray Oscilloscope that you need to know. CRO is just a vaccuum tube containing a Cathode, which emmits electrons due to thermionic emission (after its heated). The electron beam then gains enough of kinetic energy to leave the cathode and then it travels through the vacuum (REMEMBER, electrons must be in a vacuum in order to move <in air, the air molecules would stop the electrons from moving>). Then they get attracted to the anode (positive). However, before that, they have to pass a grid(negative), which would repel some of the electrons, by changing the voltage on the base it is used as a brightness control. Then, a ray of electrons would pass through a hole in the anode. On their way after passing the hole, the electrons ray will meet Y-plates and X-Plates. Y-plates would move the spot on the Fluoresecent screen afterwards up and down and the X-plates would move the coloured spot produced left and right on the fluorescent screen. At the end, the Fluorescent screen would glow, when hit by the electrons ray.
For the question you asked, its not CRO, as there is no need to make a screen glow. Its just about detection. So, you would just use a simple source, absorber, detector arrangement.
I hope this brief explanation helped. :)
Post by: MaNa on May 23, 2009, 10:46:50 pm
ya i know that what is it used for?When do we use cathode ray tube?
Cathode Ray Tube is used in terms of light (Total Internal Reflection); every time the ray of light within totally internally reflects and therefore the light ray remains within the tube. An example of its use is in the transfer of TV signals.
For Electricity, its the Cathode Ray Oscilloscope that you need to know. CRO is just a vaccuum tube containing a Cathode, which emmits electrons due to thermionic emission (after its heated). The electron beam then gains enough of kinetic energy to leave the cathode and then it travels through the vacuum (REMEMBER, electrons must be in a vacuum in order to move <in air, the air molecules would stop the electrons from moving>). Then they get attracted to the anode (positive). However, before that, they have to pass a grid(negative), which would repel some of the electrons, by changing the voltage on the base it is used as a brightness control. Then, a ray of electrons would pass through a hole in the anode. On their way after passing the hole, the electrons ray will meet Y-plates and X-Plates. Y-plates would move the spot on the Fluoresecent screen afterwards up and down and the X-plates would move the coloured spot produced left and right on the fluorescent screen. At the end, the Fluorescent screen would glow, when hit by the electrons ray.
Post by: Bani on May 23, 2009, 10:47:58 pm
LOL, I just edited my previous post just before I saw that you posted this. :Dya i know that what is it used for?When do we use cathode ray tube?
Cathode Ray Tube is used in terms of light (Total Internal Reflection); every time the ray of light within totally internally reflects and therefore the light ray remains within the tube. An example of its use is in the transfer of TV signals.
For Electricity, its the Cathode Ray Oscilloscope that you need to know. CRO is just a vaccuum tube containing a Cathode, which emmits electrons due to thermionic emission (after its heated). The electron beam then gains enough of kinetic energy to leave the cathode and then it travels through the vacuum (REMEMBER, electrons must be in a vacuum in order to move <in air, the air molecules would stop the electrons from moving>). Then they get attracted to the anode (positive). However, before that, they have to pass a grid(negative), which would repel some of the electrons, by changing the voltage on the base it is used as a brightness control. Then, a ray of electrons would pass through a hole in the anode. On their way after passing the hole, the electrons ray will meet Y-plates and X-Plates. Y-plates would move the spot on the Fluoresecent screen afterwards up and down and the X-plates would move the coloured spot produced left and right on the fluorescent screen. At the end, the Fluorescent screen would glow, when hit by the electrons ray.
Post by: Bani on May 23, 2009, 10:50:50 pm
CRT- light
CRO- to make screen glow
Post by: MaNa on May 23, 2009, 10:57:55 pm
Is it clear now?naahin !!!
CRT- light
CRO- to make screen glow
kinda
anyways i guess i cnt think anymore
uffh GUYS HELP ME I CANT STUYDY BUT I WANT TOO ANY SUGGESTIOZN
Post by: Bani on May 23, 2009, 11:03:18 pm
If you remember Total Internal Reflection, you will be able to understand the use of Cathode Ray Tube.(CRT)Is it clear now?naahin !!!
CRT- light
CRO- to make screen glow
kinda
anyways i guess i cnt think anymore
uffh GUYS HELP ME I CANT STUYDY BUT I WANT TOO ANY SUGGESTIOZN
and I think you know when CRO is used (to make the screen glow). The question you asked about only asked to draw apparatus to detect the Beta particles. So, in this case, the simple source, absorber, detector apparatus would be drawn.
To concentrate more, just think of the fruitful result you'd get if you study hard. Oh, by the way, its 1:00, so u'd better be able to concentrate in the morning. :)
Post by: zubair_slipknot on May 24, 2009, 10:01:36 am
Calculate the force on the pivot when the two masses choosen are hanging from the disc????
F=ma
or F=mg
F=200x9.8
is it like this...i am sure i am wrong somewhere...plz let me know as soon as possible...thx
Post by: Hope on May 24, 2009, 10:22:54 am
the pivot, is the circle that is shaded in.. so when you add a force at a specific distance from the pivot, there will be a moment.. Do that to the other side too, and you will also get a moment.
The questions prior to the one you are asking about, wanted no net moment, this means the whole system is in equillibrium..
so for example, if you had a mass of 10N on the right, 3 m away from the pivot..the moment of the force is = 10 x 3 = 30 Nm
and to maintain equillibrium, the other side would have to balance in someway..so it could have 15N at a distance of 2 m from the pivot .. 15 x 2= 30 Nm
Hope you understood! :D
Post by: zubair_slipknot on May 24, 2009, 10:27:27 am
+rep
Post by: Hope on May 24, 2009, 10:37:33 am
It's sort of confusing when you have to draw the magnetic field pattern in a solenoid due to the current..Particularly, I'm referring to Qn 7 (a) Year- November 2001 ..
Post by: MaNa on May 24, 2009, 10:58:19 am
I get it NOOW:D hankyou i went thorugh my book so i realise i made things cconfusing:DIf you remember Total Internal Reflection, you will be able to understand the use of Cathode Ray Tube.(CRT)Is it clear now?naahin !!!
CRT- light
CRO- to make screen glow
kinda
anyways i guess i cnt think anymore
uffh GUYS HELP ME I CANT STUYDY BUT I WANT TOO ANY SUGGESTIOZN
and I think you know when CRO is used (to make the screen glow). The question you asked about only asked to draw apparatus to detect the Beta particles. So, in this case, the simple source, absorber, detector apparatus would be drawn.
To concentrate more, just think of the fruitful result you'd get if you study hard. Oh, by the way, its 1:00, so u'd better be able to concentrate in the morning. :)
Post by: nid404 on May 24, 2009, 11:09:31 am
Post by: °o.O-hash94-O.o° on May 24, 2009, 11:40:04 am
i hope this will be helpful for all
thanks
Post by: nid404 on May 24, 2009, 11:42:24 am
Post by: nid404 on May 24, 2009, 11:58:03 am
which is 7N i believe
Post by: nid404 on May 24, 2009, 02:13:25 pm
F=m*a(m in kg)
since masses here r in grams u need to convert them to kg and then multiply by ten.
Post by: Ghost Of Highbury on May 24, 2009, 02:17:00 pm
Post by: nid404 on May 24, 2009, 02:17:52 pm
Post by: Enia on May 25, 2009, 12:35:05 pm
Can anyone please explain the AC generator for me? And also why is the direction reversed every half turn and how does that happen.
Also:
Can you tell me what we are supposed to write in questions where they ask about energy changes that take place? For example for a cart traveling down a ramp and then back up (since the ramp is curved, like skating ramp thingies) Where are we supposed to stop? Like do we also mention sound or just heat and kinetic energy and gravitational potential energy?
Thanks! :)
Post by: MaNa on May 25, 2009, 12:43:03 pm
Hi. So I had a few questions.Ac generator
Can anyone please explain the AC generator for me? And also why is the direction reversed every half turn and how does that happen.
Also:
Can you tell me what we are supposed to write in questions where they ask about energy changes that take place? For example for a cart traveling down a ramp and then back up (since the ramp is curved, like skating ramp thingies) Where are we supposed to stop? Like do we also mention sound or just heat and kinetic energy and gravitational potential energy?
Thanks! :)
It consists of a recangular coil of wires that is mounted on an axle by turning the axle the coil is made to rotate between the poles of perminent magnet
as the coil rotate the magnetic field thorugh the coil changes and therefore induced EMF between the end f coil
the slip rings allow tthe transfer of the alternating current emf induced Each ring is connected to one end of the CIL WIRE ELECTRICALLY CONNECTED BY CONDUCTING CARBON BRUSH
Post by: asus on May 25, 2009, 02:07:27 pm
6 (b)...
Post by: MaNa on May 25, 2009, 02:15:52 pm
help me out with ppr 3 nov/03..speed = freqnecy * wavelength
6 (b)...
speed / frequency = wavelength
3x10^8/5*10^14
Hope u understand :)
Post by: asus on May 25, 2009, 02:21:27 pm
ermm..i know how to do that..help me out with ppr 3 nov/03..speed = freqnecy * wavelength
6 (b)...
speed / frequency = wavelength
3x10^8/5*10^14
Hope u understand :)
but..i don't think the answer same as the markschme...
Post by: MaNa on May 25, 2009, 02:23:57 pm
lemme cheak itermm..i know how to do that..help me out with ppr 3 nov/03..speed = freqnecy * wavelength
6 (b)...
speed / frequency = wavelength
3x10^8/5*10^14
Hope u understand :)
but..i don't think the answer same as the markschme...
Post by: MaNa on May 25, 2009, 02:30:18 pm
Post by: asus on May 25, 2009, 02:30:52 pm
Post by: MaNa on May 25, 2009, 02:34:07 pm
but why the ms says 6 x 10 m ???? ??? ???i really dont know :S
Post by: MaNa on May 25, 2009, 02:55:04 pm
Post by: asus on May 25, 2009, 03:13:21 pm
i guess the mark shceme is wrong
yaa..i think so..
but our answr is correct rite?..
Post by: Shogun on May 25, 2009, 03:37:56 pm
Post by: Shogun on May 25, 2009, 03:45:56 pm
velocity= frequency*wavelength
so to find wavelenght, change postioins of formulat to (velocity/frequency)
so it would be (3*10^8)/(5*10^14)
u get 6*10^-7
just exactly mana said
but mark scheme only says 6*10
its either they want only 6*10 and if u put any (^number) u still get marks OR u reaaly have to get 6*10 or the mark scheme is worng
but im pretty sure what we did is correct..
Post by: MaNa on May 25, 2009, 03:47:02 pm
hmm its true u do have to use the formulaya i guess the mark shceme is incorreect bcuz if u see the metohrd is what we did too soo yaaa
velocity= frequency*wavelength
so to find wavelenght, change postioins of formulat to (velocity/frequency)
so it would be (3*10^8)/(5*10^14)
u get 6*10^-7
just exactly mana said
but mark scheme only says 6*10
its either they want only 6*10 and if u put any (^number) u still get marks OR u reaaly have to get 6*10 or the mark scheme is worng
but im pretty sure what we did is correct..
Post by: Tutu_93 on May 25, 2009, 03:49:58 pm
I have maany doubts :S
Post by: sweetsh on May 25, 2009, 03:52:14 pm
Post by: Shogun on May 25, 2009, 03:55:55 pm
lol just joking
yup just bring them ova here
Post by: Tutu_93 on May 25, 2009, 03:58:52 pm
:-\
Post by: asus on May 25, 2009, 03:59:29 pm
hmm its true u do have to use the formula
velocity= frequency*wavelength
so to find wavelenght, change postioins of formulat to (velocity/frequency)
so it would be (3*10^8)/(5*10^14)
u get 6*10^-7
just exactly mana said
but mark scheme only says 6*10
its either they want only 6*10 and if u put any (^number) u still get marks OR u reaaly have to get 6*10 or the mark scheme is worng
but im pretty sure what we did is correct..
hey..how come u got 6*10^-7..
manah & I got 6x10^21..
Post by: Shogun on May 25, 2009, 04:02:38 pm
and i got 6x10^-7
by just deviding the velocity/frequency
(3x10^8)
------------ = 6x10^-7
(5x10^14)
Post by: Tutu_93 on May 25, 2009, 04:04:33 pm
Its the second
Thanks
Post by: Shogun on May 25, 2009, 04:05:26 pm
Post by: asus on May 25, 2009, 04:06:21 pm
tutu is tht first variant or second
and i got 6x10^-7
by just deviding the velocity/frequency
(3x10^8)
------------ = 6x10^-7
(5x10^14)
yaa..i think yours is correct...
we need to simplify the bottom one first...
silly.. ::)
Post by: Shogun on May 25, 2009, 04:20:04 pm
f=force and d=distance) the product must be same. (then only they are balanced i.e in equilibrium)
the distance are given for each hole to the pivot. so i recomend to take the first hole(with distance 4cm) and add mass 200g at one side of the pivot. and on the other side, add mass 100g on the second hole (with disatnce 8 cm from teh pivot)
so when using the formula "fxd " u get on one side: 200x4=800N
and
on the other side: 100x8=800N
- see both have the same product so it is now they are balanced(in equilibrium)
ans2b) the disc does not move or rotate as u put the mass so they are balanced so no turning effect which means no moment.
c)use formula "fxd"
200x4=800N
100x8=800N
d)this is the force of pivot which is downwar to get tht simply add the masses u put
100+800=900g
but rmember u can choose any mass at any distance but the product with equation "fxd" must be same
thts all,hope this helped, any confusion or difficulties or help u need, im all here
the distance are given for each hole to the pivot. so i recomend to take the first hole(with distance 4cm) and add mass 200g at one side of the pivot. and on the other side, add mass 100g on the second hole (with disatnce 8 cm from teh pivot)
so when using the formula "fxd " u get on one side: 200x4=800N
and
on the other side: 100x8=800N
- see both have the same product so it is now they are balanced(in equilibrium)
ans2b) the disc does not move or rotate as u put the mass so they are balanced so no turning effect which means no moment.
c)use formula "fxd"
200x4=800N
100x8=800N
d)this is the force of pivot which is downwar to get tht simply add the masses u put
100+800=900g
but rmember u can choose any mass at any distance but the product with equation "fxd" must be same
thts all,hope this helped, any confusion or difficulties or help u need, im all here
Post by: Tutu_93 on May 25, 2009, 04:32:12 pm
Ill contiue solving nw .. just dont go lol
Post by: Shogun on May 25, 2009, 04:36:14 pm
dnt frgt to +rep me (man i hate sayin this ,it makes me feel im selfish, but it seems it works for others)
Post by: Tutu_93 on May 25, 2009, 04:37:10 pm
Question 4a ?? is it Brownian motion ??? :-[
Post by: Shogun on May 25, 2009, 04:39:40 pm
Post by: Tutu_93 on May 25, 2009, 04:45:52 pm
Why should we wait 4 it ??
Post by: Shogun on May 25, 2009, 04:54:04 pm
in short, so the temperature of all ice is constant
Post by: Tutu_93 on May 25, 2009, 05:17:06 pm
Q 9a
Post by: Shogun on May 25, 2009, 05:20:25 pm
Post by: Dimwit on May 25, 2009, 05:34:56 pm
hope all will be friendly..because every1 seems to be so united..
ts rly nice..
:) :P
Post by: Ghost Of Highbury on May 25, 2009, 05:36:36 pm
Post by: Tutu_93 on May 25, 2009, 05:46:30 pm
Post by: Shogun on May 25, 2009, 05:50:16 pm
Post by: Shogun on May 25, 2009, 05:51:03 pm
Post by: pshycho on May 25, 2009, 06:32:05 pm
Post by: Shogun on May 25, 2009, 06:33:33 pm
Post by: Tutu_93 on May 26, 2009, 07:58:50 am
Question 5b .. Why did they added the mass of the beaker ?? with the mass of water ???
Post by: astarmathsandphysics on May 26, 2009, 08:07:27 am
Post by: Tutu_93 on May 26, 2009, 08:13:51 am
Post by: Ghost Of Highbury on May 26, 2009, 08:18:41 am
Post by: nid404 on May 26, 2009, 08:20:52 am
This will let u find the mass of the water( mass of beaker+water - mass of beaker)
And this is what u need other than the energy used to find sp.latent heat of fusion
Post by: examsaresoon on May 26, 2009, 08:41:50 am
Post by: nid404 on May 26, 2009, 08:44:16 am
e.g. a property that changes a little in one half of the temperature range and much more in the other half would not be suitable
Post by: Aodian on May 26, 2009, 09:40:41 am
Post by: MaNa on May 26, 2009, 09:48:37 am
P=VI
I= Charge/time
E=IV
Vs/Vp=Ns/Np where ( Vs= secondary output voltage
Vp= Primary inpu voltage
Ns number of tumrns in secondary coil
Np number of turns in primary coil)
IpVp=IsVs (where Vp n Vs are same as above BUT Ip is Cureent in priamry coil Is is curent in secondary coil)
Power(loss) I^2 *R
Post by: Shogun on May 26, 2009, 10:08:11 am
to find current (I)= charge(Q)/time(t)
to find charge (Q)= current (I) x time (t)
to find time (t)= charge (q) / currebt (I)
to find resistance,voltage,current interms of resistance,voltage or current:
to find current (I)= voltage (v)/ resistance (R)
to find voltage(V)= Current(I) x rsistance (R)
to find resistance (R)= voltage (v) / Current (I)
formulas got to do with power and energy(workdone):
to find the power(p): voltage (v) x Current (I) (the unit of power is watts)
to find the loss power: square of current x resistance (I^2 x R)
to find energy(E) which is also workdone: voltage (v) x Current (I) x Time (t)
OR
power(p) x time(t) (unit of is joules)
formulas of transformer:
to find number of turns in secondary or primary coils OR the secondary or primary voltage:
secondary voltge (Vs) number of turns of secondary (Ns)
---------------------- = ----------------------------------
Primary voltage (Vp) number of turns of primary (Np)
to find voltage or current in an 100% efficient trnasformer=
voltage in primary(Vp) x current in primary(Ip) = voltage in secondary(Vs) x current in secondary(Is)
OR
power in primary = power in secondary (cuz voltage(V) x current (I)= power)
more resistance formula:
to find total resistance aranged in SERIES : just add all resistance (R1+R2+R3),etc
to find tpatal resistance where resistors are arange in parallel : just add 1/r
(1/R1 + 1/R2 + 1/R3 = 1/R) etc then at the end reverse it by making 1/R to R/1 to get (R) resistance
and no formulas for CRO
well thts all i guess
any confusion or help u need just ask me
Post by: Aodian on May 26, 2009, 11:59:39 am
Post by: MaNa on May 26, 2009, 12:02:24 pm
Thanx a lot Manah and Shogun!No problem but dont forget + rep ;)
Post by: Aodian on May 26, 2009, 12:38:28 pm
lol no problem.. but still a noob here lol.. so show me how to add repThanx a lot Manah and Shogun!No problem but dont forget + rep ;)
Post by: Aodian on May 26, 2009, 12:40:04 pm
Post by: Bani on May 26, 2009, 01:07:40 pm
2a) put different value of masses on bothe sides of the pivot but make sure tht after using the formula (fxd) (whereHey,the formula for calculating the moment is f*d, and when we multiply 200g by 4cm, aren't we multiplying the mass by the distance? Aren't we first suppossed to convert the mass into force by multiplying it with 10 (F=ma)? and the unit for moment is supposed to be Nm, isn't it? Please help. Thanks in advance :)f=force and d=distance) the product must be same. (then only they are balanced i.e in equilibrium)
the distance are given for each hole to the pivot. so i recomend to take the first hole(with distance 4cm) and add mass 200g at one side of the pivot. and on the other side, add mass 100g on the second hole (with disatnce 8 cm from teh pivot)
so when using the formula "fxd " u get on one side: 200x4=800N
and
on the other side: 100x8=800N
- see both have the same product so it is now they are balanced(in equilibrium)
ans2b) the disc does not move or rotate as u put the mass so they are balanced so no turning effect which means no moment.
c)use formula "fxd"
200x4=800N
100x8=800N
d)this is the force of pivot which is downwar to get tht simply add the masses u put
100+800=900g
but rmember u can choose any mass at any distance but the product with equation "fxd" must be same
thts all,hope this helped, any confusion or difficulties or help u need, im all here
Post by: hala999 on May 26, 2009, 01:12:59 pm
i need help wid nov 08 1st variant q 5 c
(c) Using a 40 W heater, 16.3 g of ice is melted in 2.0 minutes. The heater is then switched
off. In a further 2.0 minutes, 2.1 g of ice is melted.
Calculate the value of the specific latent heat of fusion of ice from these results.
Post by: emi on May 26, 2009, 03:30:00 pm
change the minutes to seconds , subtract the first and final mass of ice melted and simple divide with energy
Post by: MaNa on May 26, 2009, 03:34:41 pm
hey guyz !!!mass -16.3-2.1=14.2
i need help wid nov 08 1st variant q 5 c
(c) Using a 40 W heater, 16.3 g of ice is melted in 2.0 minutes. The heater is then switched
off. In a further 2.0 minutes, 2.1 g of ice is melted.
Calculate the value of the specific latent heat of fusion of ice from these results.
latens heat of fusion= energy
therefore 40*120=4800J
ther fore latent heat of fusion equals
4800/14.2
338J/g
hopes that explians
Post by: Tutu_93 on May 26, 2009, 03:38:07 pm
What do the mean when they say that Gama rays interaction with gas molecules is very less ??? ???
Post by: annie_angel on May 26, 2009, 03:41:33 pm
Post by: Shogun on May 26, 2009, 03:46:29 pm
2a) put different value of masses on bothe sides of the pivot but make sure tht after using the formula (fxd) (whereHey,the formula for calculating the moment is f*d, and when we multiply 200g by 4cm, aren't we multiplying the mass by the distance? Aren't we first suppossed to convert the mass into force by multiplying it with 10 (F=ma)? and the unit for moment is supposed to be Nm, isn't it? Please help. Thanks in advance :)f=force and d=distance) the product must be same. (then only they are balanced i.e in equilibrium)
the distance are given for each hole to the pivot. so i recomend to take the first hole(with distance 4cm) and add mass 200g at one side of the pivot. and on the other side, add mass 100g on the second hole (with disatnce 8 cm from teh pivot)
so when using the formula "fxd " u get on one side: 200x4=800N
and
on the other side: 100x8=800N
- see both have the same product so it is now they are balanced(in equilibrium)
ans2b) the disc does not move or rotate as u put the mass so they are balanced so no turning effect which means no moment.
c)use formula "fxd"
200x4=800N
100x8=800N
d)this is the force of pivot which is downwar to get tht simply add the masses u put
100+800=900g
but rmember u can choose any mass at any distance but the product with equation "fxd" must be same
thts all,hope this helped, any confusion or difficulties or help u need, im all here
true, sorry. so then we have to multiply them by 10, however we get same product, but u must multiply by 10
cuz mass x10 , but first we must convert the masses to killogram then multiply by 10 to get the force. but then thank u bani for correcting me
Post by: Shogun on May 26, 2009, 04:01:23 pm
can anyone help wid the time base control ; base emitter collector and how the resistance works?? ??? ???
the time base system works for the x plates on the cathode ray osclliscope(CRO), the thing is tht, dpending on time the voltage goes zero between the plates then after acertan period of time say 0.5 secs the voltage gose up to its original value, how does this help? the x plate is ment to let the beams of electrons move horizonataly (left and right) so it hits the screen (on both the left and right side). so to do this, lets say abeam of elctrones in an CRO is coming and as it passes through the x plates(which is charged with postive and negative charge) the beam of electron (which is negative in charge) deflects towards the postive charge plates.
lets say the positive plate is aranged on the right, so when thier is voltage the beam deflects to the right after CERTAIN SET TIME the voltage goes zero (so no charged plate) and the beam returns to its original path (i.e the left side) then again after a certain set time the voltage goes up and the beam of electrons deflects to the right again.. so this is how the beam moves right and left with the help of x plates whic is TIME BASE system.
base emiter stuff...
the base and emmiter and collector wires are used in a transistor. the for the lamp to work (which is uually placed on the path of colletor emitter path) there must be a current on the base current and there must be a suitable potential difference of 0.6v across the base emitter path.
these conditions are needed for the transistor to work which acts as an automatic switch to switch on the lamp (which is usually placed in the collector -emitter path)
resistance stuff,
they say to the current "get the hell outta here" , u see they act as aopposition to the flow of current in the circuit, it does not let the current to pass through. it blocks the path of the current. with variable resistor u can change the amount of blockage, which means u can allow certain ammount of current to pass and flow through.
any more help or confusion or difficulties,plz do ask me.
Post by: emi on May 26, 2009, 04:17:14 pm
deflection in magnetic field
deflection in an electric field
thanks
Post by: Shogun on May 26, 2009, 04:31:41 pm
can some one explain for me for each of " alpha, gama, beta " radiations their
deflection in magnetic field
deflection in an electric field
thanks
deflections of rays in magnetic fields
alpha is positively charged so in magnetic field in to the paper (the north pole faced towards a paper) (uding flemings left hand u point ure index finger just like the way u would point at somone and with the thumb up and ure middle finger pointing towards the right(which is the direction alpha rays)) so doing this would indicate tht alpha rays deflects upwards.
however the beta rays(negatively charges) moves opposite to the deflection of alpha rays (i.e downwards but with the same conditions set as experssed for the alpha rays)
whereas in gamma rays, no deflection in magntic field.
deflections of rays in an electrical field.
lets say there are 2 charged plates place over another(with gap inbetwwen), one is postively charged plate which is for example the upper plate, and the lower plate is negatively charged. alpha rays deflect yowards the negative side (i.e downwards) as it is postively charged, whereas the beta rays deflects towards the positively charge plate(i.e upwards, just opposite of alpha rays). gamma rays do not deflect in electric fields either.
hope this helped, any confusion difficulties or help needed, plz do ask me
Post by: emi on May 26, 2009, 04:49:01 pm
and i understood each word you said =]
<33
Post by: Shogun on May 26, 2009, 04:50:55 pm
Post by: Tako93 on May 26, 2009, 09:58:07 pm
i was wondering if there are a any revision notes which may help ??>
THX
Post by: MaNa on May 26, 2009, 11:56:03 pm
Paper 1 (2008may/june)
Q-37
n one more thing
Beta particals are elctions, n electrons are found in the OUTER ORBIT right
so in Q -38 (same year/session) the ans in A how?>
Post by: astarmathsandphysics on May 27, 2009, 12:02:10 am
can sme body explain MCQc.the voltage is in the ratio of the resistances
Paper 1 (2008may/june)
Q-37
n one more thing
Beta particals are elctions, n electrons are found in the OUTER ORBIT right
so in Q -38 (same year/session) the ans in A how?>
All radiation comes from the nuclues. A neutrom changes in to a proton: n>p++e-
Post by: MaNa on May 27, 2009, 12:04:03 am
but isnt it IR= Vcan sme body explain MCQc.the voltage is in the ratio of the resistances
Paper 1 (2008may/june)
Q-37
n one more thing
Beta particals are elctions, n electrons are found in the OUTER ORBIT right
so in Q -38 (same year/session) the ans in A how?>
All radiation comes from the nuclues. A neutrom changes in to a proton: n>p++e-
so if R decreases V decreases too bcuz they r propotional:S
Post by: jkiam11 on May 27, 2009, 08:19:46 am
Why does cutting the magnetic fields with a wire generate a current?
Post by: astarmathsandphysics on May 27, 2009, 08:22:42 am
Post by: Shogun on May 27, 2009, 09:59:58 am
Post by: MaNa on May 27, 2009, 10:26:11 am
anyone ?? can answer?but isnt it IR= Vcan sme body explain MCQc.the voltage is in the ratio of the resistances
Paper 1 (2008may/june)
Q-37
n one more thing
Beta particals are elctions, n electrons are found in the OUTER ORBIT right
so in Q -38 (same year/session) the ans in A how?>
All radiation comes from the nuclues. A neutrom changes in to a proton: n>p++e-
so if R decreases V decreases too bcuz they r propotional:S
Post by: Shogun on May 27, 2009, 10:29:46 am
Post by: Shogun on May 27, 2009, 10:41:58 am
u see the job of the potential devider is tht it gives some amount of voltage to another part of the circuit (ie. the part with 100v potential devider on the second diagram) so what happened was tht both potential devider are 100v one of them becam 90 so as a result giving the missing 10v to the other potential devider with 100v making it 110v. this is the job of potential devider, it devides voltage to diffrernt amounts to differnt parts of the circuit. it has nothing got to do with r=vi cuz its not a resistor its a potenmtial devider.
the question states the job of the potential devider. and yea the units are in ohms but as VOLTAGE INCREASES THE RESISTANCE INCREASES.
and the answr for q38 is A cuz beta particle are elctorns as beta is negatively charged, and all rediations happens from nucleus
i hope this helped, any confusion difficulties or help needed plz do ask, and if they are correct according to the mark scheme (which is supposed to be) or if my explainaiton suits or is understandable plz do +rep me.
Post by: astarmathsandphysics on May 27, 2009, 10:52:49 am
Post by: annie_angel on May 27, 2009, 02:19:53 pm
THANK U SO MUCH!!!these r actually da simplest meaning for me...:D...+repcan anyone help wid the time base control ; base emitter collector and how the resistance works?? ??? ???
the time base system works for the x plates on the cathode ray osclliscope(CRO), the thing is tht, dpending on time the voltage goes zero between the plates then after acertan period of time say 0.5 secs the voltage gose up to its original value, how does this help? the x plate is ment to let the beams of electrons move horizonataly (left and right) so it hits the screen (on both the left and right side). so to do this, lets say abeam of elctrones in an CRO is coming and as it passes through the x plates(which is charged with postive and negative charge) the beam of electron (which is negative in charge) deflects towards the postive charge plates.
lets say the positive plate is aranged on the right, so when thier is voltage the beam deflects to the right after CERTAIN SET TIME the voltage goes zero (so no charged plate) and the beam returns to its original path (i.e the left side) then again after a certain set time the voltage goes up and the beam of electrons deflects to the right again.. so this is how the beam moves right and left with the help of x plates whic is TIME BASE system.
base emiter stuff...
the base and emmiter and collector wires are used in a transistor. the for the lamp to work (which is uually placed on the path of colletor emitter path) there must be a current on the base current and there must be a suitable potential difference of 0.6v across the base emitter path.
these conditions are needed for the transistor to work which acts as an automatic switch to switch on the lamp (which is usually placed in the collector -emitter path)
resistance stuff,
they say to the current "get the hell outta here" , u see they act as aopposition to the flow of current in the circuit, it does not let the current to pass through. it blocks the path of the current. with variable resistor u can change the amount of blockage, which means u can allow certain ammount of current to pass and flow through.
any more help or confusion or difficulties,plz do ask me.
Post by: Shogun on May 27, 2009, 04:18:47 pm
Post by: zara on May 27, 2009, 04:25:11 pm
i need help with CRO....
esp the calibration part....n ven they ask how these graphs are produced by the CRO...
i hv no clue to it ???
Post by: sweetsh on May 27, 2009, 04:42:04 pm
Post by: Shogun on May 27, 2009, 04:42:55 pm
cathode ray oscillascope. has 6 parts.
the filament: it goes through thermionic emiision(where a substance is heated it releases electrons) this filament is heated and releases electorns with negative charge.
the anode grid: it has a positve charge. this controls the nrightness (ill tell u how later)
the cathode grid: it has a negative charge, this allows the beam of electron (the electrons emitted when tht filament was heated)
the y plates:hese have plates with (+) and (-) charge and are attached vertically to each other on the tube of the CRO. this helps the beam of electrons move up and down so the beam of electrons spread evenly (up and down) on the screen.
the x plate: these have plates with (+) and (-) charge and are attached horizontilly to each other on the tube of the CRO. these help the electrons move (left and right) as it hits the screen.
the screen: at the end of the CRO is the screen (made of fluroscent usually) when electorns hit this screen it glows.
without x plate and y plates u will see the beam of electrons hitting one point of the screen only (so only tht part glows) for eg:on TV (just an example) , if with out x plates and y plates, picture can only be seen as a spot of light (picture) on the screen. but with x and y plates the electrons are able to reach both (up and down) and (right and left) with the help of y plates and x plates respectively. (ill tell u how they work later))
how does the OCR work?
first the filament is heated, beams of electrons are emitted (this is callerd thermionic emission). they go throu the cathode. what does cathod do? Cathode are negatively charge (-) and so are the beam of electrons, so repulsion take place due to similar charges allowing some beams of electrons to "stay back". This control the brightness cuz "the more number of electrons hittin the screen, the brighter the pic comes on the screen". ok, then the beams pass through the anode. what does the anode do? Anode is positively charged (+) and the beam of electrons are oppesitely charged. this anode atracts the beam of electron giving the "boost" or "acceleration" and to travel in a straight line (beam). then it reaches the Y plates. as i told u the help the electrons move up and down . they are plates with voltages (charged with (+) and (-))). they are GIVEN WITH A.C VLTAGE because if it was D.C then the elctrons would only move up OR down depending on the position of the positively charged plate ( as beam of electron is negatively charged). u see, A.C current changes its direction so the plates change their charges, whic means (+) become (-) then later (-) becomes (+). so (+) charge changes its positon and so does the beam of electron which changes its direction of deflection. this helps the electrons to touch both up and down of the screen.
the X plate are same, except they help the electrons to move right and left they are also charged except tht they are aranged horizontally. they are time base. the work with time, how? by letting the voltage between these plates go 0 then after sometime go to a certain value. how tghis helps? as the voltage has acertain value thts not 0 the beam deflects to towards positively charged plate. then when after a certain time it the voltage goes 0 immediately. this all ows the beam of electrons to GO BACK its old path (which was before deflection at X PLATE), then vise versa. this helps the electrons go left and right on the screen.
U might ask what in x plate there is time base and in y plates are AC current? why cant the put AC on the xplates too? This is because i think tht the time base system helps beam to go in the REQUIRED or aprropriate horizontal path.
then finally the electrons reaches the screen in every direction (with the help of x and y plates) which causes the whole fluroscent screen to glow or lit.
however i donthink we have any calibrations or how does it show them as graph explainations in our syllabus..
any help needed or any confusion im all here m8....
i hope this helpd
Post by: Shogun on May 27, 2009, 04:49:24 pm
Post by: zara on May 27, 2009, 05:08:37 pm
+rep to u...
n i actually meant the waveforms nly ven i askd abt the graphs...
so plz explain this as well.....
this forum's workin too slow....dats the reason for m late replies...srry for dat..
Post by: Shogun on May 27, 2009, 05:10:29 pm
Post by: Shogun on May 27, 2009, 05:14:49 pm
this plot shows the graph where it displays wavefroms on the screen, the inputs are calibrated on the knob, this is how its calibrated and gets the wavefrom in a graph like type/format, the graph or wavefrom is produced based on the set input and its variation of the wavefrom with time. how is it diplayed on the screen? just as the way i explained u how the OCR works.
any confusion or difficulties u have or any help u need plz do ask me.
Post by: zara on May 27, 2009, 05:28:46 pm
for now this is f9...if i fynd ne probs ill ask later...
Thanks a lot.. ;D
Post by: Shogun on May 27, 2009, 05:33:20 pm
Post by: qwert101 on May 28, 2009, 12:45:51 pm
thanks
Post by: reishamix on May 28, 2009, 03:43:22 pm
howd u explain
why a secondary output is obtained even though there is no electrical connection between the primary
and secondary coils??
::)
Post by: Shogun on May 28, 2009, 03:52:51 pm
anybody know the limits of accuracy your numerical questions should be? like how many significant figures/ decimal places? :-[
thanks
hey, all numerical answers must be in 3 significant figures. its easier and foun much acceptable by mark schemes.
Post by: Shogun on May 28, 2009, 04:00:05 pm
in transformers ..
howd u explain
why a secondary output is obtained even though there is no electrical connection between the primary
and secondary coils??
::)
this question came in may june 2000 physics paper3, ill explaint it to u in aminute
Post by: Shogun on May 28, 2009, 04:10:01 pm
the alternating current from the primary coils is cut by the secondary coil ,inducing it with emf. so the secondary coils now have an emf enduced..
any help or confusion u have do ask me..
Post by: crypsAnity on May 28, 2009, 04:20:06 pm
A Secondary Output is obtained because when an ac Current passes through the Primary Coil .. a constantly
changing magnetic field is produced.. so although the two coils have no wires linking them the magnetic field
produced by the first coil reaches and "cuts" (As its constantly changes its direction for ac current) the secondary coil
therby inducing a current in it .. which is known as "Electromagnetic Induction" .. Faraday uncles theory .. =]
Post by: Shogun on May 28, 2009, 04:27:08 pm
Post by: crypsAnity on May 28, 2009, 04:29:24 pm
Post by: reishamix on May 28, 2009, 04:29:55 pm
or u could with the above guy, but they both have a similar answer.
dude
u jus changed ur answer
"this is due to the iron core u see, very small amount of electrical filed is present in the wires which induces and emf on the secondary coild due to the iron core."
wht r u doing?
Post by: Shogun on May 28, 2009, 04:33:31 pm
i was gonna say to the other guy tht he did not answer to the question where it was said with no electric current, then i reallised wat i wrote was truly freaken complicated, so i thought i better change it b4 u read it and get confused....
Post by: reishamix on May 28, 2009, 04:38:56 pm
yup , didnt read the question well,my mistake
i was gonna say to the other guy tht he did not answer to the question where it was said with no electric current, then i reallised wat i wrote was truly freaken complicated, so i thought i better change it b4 u read it and get confused....
lol i did get confused
By the way .. cryps is a gurl ..
Thanks tho!!
=]
Post by: crypsAnity on May 28, 2009, 04:39:40 pm
Post by: Shogun on May 28, 2009, 04:49:47 pm
Post by: qwert101 on May 28, 2009, 06:47:54 pm
anybody know the limits of accuracy your numerical questions should be? like how many significant figures/ decimal places? :-[
thanks
hey, all numerical answers must be in 3 significant figures. its easier and foun much acceptable by mark schemes.
thanks :P
Post by: Shogun on May 28, 2009, 06:48:22 pm
Post by: crypsAnity on May 28, 2009, 06:50:16 pm
could anybody please tell me how can you use a cro and measure applied voltage?
and the more important one .. the time base right .. whats the difference between it and an xplate to which alternative current is fed?
(if there is any.. because i thto before there wasnt .. but then saw this diagram on the book and got confused because you see there were
two diagrams one which said "after time base on and the current fed to yplates are alternative.." - it was a sine wave ..
and the otehr where i got confused was "after an alternating current being fed to both x and y plates" .. it had and y=x shaped linear graph.. ) help anyone please.. seems like the only stuff in phy dont get .. (so far)
p.s *prays* .. hope CRO's never come ..
Post by: Shogun on May 28, 2009, 06:57:52 pm
Post by: Shogun on May 28, 2009, 07:04:52 pm
Post by: Shogun on May 28, 2009, 07:27:59 pm
when an AC current is supplied the postive charge changes its position so the beam of electron deflects in different direction continuosly thus causing a sine curve(up and down, up and down..etc)
this would have the same effect with time base on ,cuz here the position of charge does not change, the amount of voltage changes but i think it would have the same effect as as, excep it would be steepr and sharper turns..
Post by: crypsAnity on May 28, 2009, 08:10:59 pm
Exactly man.. thats what i thought.. ohh.. I didnt get it from the book .. ts these notes by some guy called
prof A.S Ibrahim .. got it off from some guy in school who had em.. anyhows shoudlnt rely on them much see.. anyways
I have the Hodder Murrays's IGCSE Physics by Tom Duncan and Heather Kennet .. hmmm love tht one...
anyways.. thanks a bunch.. i get the y voltage thing now.. =] u best of lucks for exams mate!
Post by: saadmannan on May 28, 2009, 11:26:16 pm
1) Thermistor
2)Transistor
3) Diode Rectification
4) LDR
Post by: astarmathsandphysics on May 29, 2009, 12:18:53 am
Can somebody plz explain me
1) Thermistor
2)Transistor
3) Diode Rectification
4) LDR
Semiconductors have in common that their resistance goes down as temperature(thermisyor) or light level(LDR) goes up. A transistor is basically an electronic switch and a diode rectifier changes ac into dc
Post by: Enia on May 29, 2009, 06:53:29 am
Thanks.
Post by: Enia on May 29, 2009, 07:13:50 am
Post by: SGVaibhav on May 29, 2009, 09:16:17 am
Post by: Enia on May 29, 2009, 12:00:29 pm
Dont u guy find it embarrassing to use the Flemming's left hand and right hand rule in the examination hall?
LOL I KNOW right? But there is no other way! xDDD And I sometimes, ok always, look like an idiot doing it, with my eyes crossed and trying to figure out which finger is for what! I look like a complete moron xD
Lets just hope its a straightforward question so we don't get embarrassed TOO much .
Oh and am I the only one who thinks Flemming used his hands waaay too much for it to be healthy? =P
Post by: SGVaibhav on May 29, 2009, 12:13:22 pm
Post by: Shogun on May 29, 2009, 12:27:15 pm
Post by: SGVaibhav on May 29, 2009, 12:36:32 pm
Post by: SGVaibhav on May 29, 2009, 12:40:53 pm
Post by: Shogun on May 29, 2009, 12:41:22 pm
Can somebody plz explain me
1) Thermistor
2)Transistor
3) Diode Rectification
4) LDR
hi,thermistor is a type of a resistor, except tht it works depending on the temperature. if the temperature was at cold the resistance increases, and as resistance increases the current is acroos it reduces.
so in short the lower the temperature the higher the resistance.
now, the transistor, u see, is an elctronic switch, an automatic switch u see, it has 3 sets of wire joind as a circuit, the 3 wires are base,collector and emitter.it allows somthing (eg: a lamp) to work depending on 2 condition which are: 1) there must be a current on the base wire(ie. there must be a base current)
2)the potential difference(P.D) betwwen base and emitter path must be atleast 0.6volts.
if these 2 conditions are not there then the lamp is automatically switched off.
then therez the diode, its positive side must be connected to the positive side of the battery(the same was the ammeter is connected) then it will allow current to flow throgh (i.e no resistance). what is its job? it changes an AC current to DC.Now, if the positve side of this device is connected to the negative side of the battery the resistance would be high and would not conduct electricity(i.e it wont allow current to pass).
then finally the light dependant resistor(LDR). this thing is like the thermistor...except it depends on light.if light falls on it the resistance decreases thus allowing current to pass, in short, if light touches it the resistance decreases.
hope u understand, any difficulties, or problems, or confusion u have plz do ask me.
Post by: cactus_360 on May 29, 2009, 03:22:41 pm
Post by: leebux101 on May 29, 2009, 03:45:51 pm
i am not sure abt this...u shud ask someone else just in case...
good luck!
Post by: Shogun on May 29, 2009, 04:16:30 pm
can anyone explain potential divider briefly.................
yup wat bakhtawar said was correct, it devides the voltage accross the circuit to parts or devices.
for eg: this much voltage1 for device 1 and this voltage2 is for device2,what does the potential devider do is tht it can take some voltag1 to voltage2 so now device2 has more voltage. its job is to devide the voltage.
Post by: sweetsh on May 29, 2009, 04:57:19 pm
Post by: Shogun on May 29, 2009, 05:16:52 pm
hope u understand
Post by: sweetsh on May 29, 2009, 05:19:55 pm
And thank you.
Post by: Shogun on May 29, 2009, 05:21:55 pm
Post by: Summer :] on May 29, 2009, 05:35:18 pm
Post by: X Abdulrahman X on May 29, 2009, 05:43:02 pm
hey does anybody have notes to do with magnestism,generators,motors??? my weakness :-\
http://www.physclips.unsw.edu.au/jw/electricmotors.html
Enjoy :)
Post by: Summer :] on May 29, 2009, 06:51:36 pm
hey does anybody have notes to do with magnestism,generators,motors??? my weakness :-\
http://www.physclips.unsw.edu.au/jw/electricmotors.html
Enjoy :)
Thankyouuuuuuuuuuuuuuu!!!! :D :D
have u got any idea how a thermocouple thermometer works?? :P and umm i have a few questions about
Linearity of the thermometers, what does it mean??
Post by: islu_jf on May 29, 2009, 06:55:44 pm
Post by: cactus_360 on May 29, 2009, 06:57:28 pm
Post by: X Abdulrahman X on May 29, 2009, 07:11:44 pm
hey does anybody have notes to do with magnestism,generators,motors??? my weakness :-\
http://www.physclips.unsw.edu.au/jw/electricmotors.html
Enjoy :)
Thankyouuuuuuuuuuuuuuu!!!! :D :D
have u got any idea how a thermocouple thermometer works?? :P and umm i have a few questions about
Linearity of the thermometers, what does it mean??
a thermocouple consits of 2 wires of 2 different materials joined together, when 1 junction is hotter then the other and electric current flows and produces a reading on a sensitive meter which depends on the temp, difference. they are used in industry, usually measuring -250C to about 1500C
Post by: astarmathsandphysics on May 29, 2009, 07:19:15 pm
Can u pleeeeeeeeeeeeeeeezzz tel me what is LDR and and the light emittng one.. what are they used for??????
LDR might be used yo turn streetlamps on at night. The detect the light level and when the light falls below a certain level the lights turn on
LEDs are used a light in electronics as one switches
Both are semiconductors and dont consume much power
Post by: astarmathsandphysics on May 29, 2009, 07:25:33 pm
linearity means that distance between each degree on da scale is the same!!!
yes
Post by: Lotus21 on May 29, 2009, 07:47:20 pm
Please may you help me with these two questions:
1) A scientist wishes to investigate the deflection of ?-particles by an electric field. Draw a labelled diagram to suggest a suitable experimental arrangement. (Paper 3 November 2005) I don't even know how to draw electric field lines.
2) How to expand a) sensitivity b) range of a thermometer.
Thanks a lot.
Post by: Kasa on May 29, 2009, 08:07:07 pm
Hi everyone,
Please may you help me with these two questions:
1) A scientist wishes to investigate the deflection of ?-particles by an electric field. Draw a labelled diagram to suggest a suitable experimental arrangement. (Paper 3 November 2005) I don't even know how to draw electric field lines.
2) How to expand a) sensitivity b) range of a thermometer.
Thanks a lot.
Hi,
I am not sure about your first question, but i do know the answer to the second.
To expand the sensitivity of a thermometer:
You make the capillary tube finer so that when the liquid expands it has a longer distance to travel.
Also, you could make the bulb of the thermometer bigger.
I don't know about the range though..
Hope this helps!
Post by: islu_jf on May 29, 2009, 08:12:52 pm
now b/w them u put after the source a sheet bt it has a hole in it.. and then after that u put a Y-plates kind.. for the "charged metal plates"
2) for sensitivity..
u know there are lines on the thermometer ... u make these lines closer together.. so any slight change.. it will be detected./
and for the range .. make the two fixed points have a large differnce b/w them..
I hope u'll understand. :)
Post by: astarmathsandchemistry on May 30, 2009, 04:26:35 pm
please if anyone can attach very good notes on radioactivity i would be very grateful thanks :D
Post by: nid404 on May 30, 2009, 04:46:50 pm
hope this helps
Post by: astarmathsandchemistry on May 30, 2009, 04:49:08 pm
visit http://www.gcse.com/radio/rad.htmthanks man really helpful
hope this helps
+rep :D
Post by: nid404 on May 30, 2009, 04:52:42 pm
visit http://www.gcse.com/radio/rad.htmthanks man really helpful
hope this helps
+rep :D
i think docbrowns is better. great notes
http://www.docbrown.info/page03/3_54radio.htm
this will certainly help
Post by: Jerry_LA on May 30, 2009, 04:54:26 pm
thnk you guys
Post by: astarmathsandchemistry on May 30, 2009, 05:28:03 pm
Post by: nid404 on May 30, 2009, 05:32:27 pm
thanks guys, i really appreciate it!
i think u -repped me :(
Post by: Ghost Of Highbury on May 30, 2009, 05:41:03 pm
did anyone even see the ppt..i uploaded..lol!!
Post by: astarmathsandchemistry on May 30, 2009, 05:42:25 pm
nop i didnt, +rep for u :)thanks guys, i really appreciate it!
i think u -repped me :(
Post by: nid404 on May 30, 2009, 05:44:45 pm
nop i didnt, +rep for u :)thanks guys, i really appreciate it!
i think u -repped me :(
hey thanks ;D
Post by: susman on June 01, 2009, 05:05:51 pm
thanks alot you all
it was kinada like note revision reading your posts:D
plus I will also be asking questions.:)
1)How to make lenz drwaing...(like draaw the rays from object to mirror and then refract thru the preincipal focus and stuff any notes on that..?
2)can any1 expalin potectial divider in detail with examples.. i really didnt understand till now...
3) what is caron dating..
thanks in advance...
Post by: esso on June 01, 2009, 05:50:35 pm
IT SAYS
A 12 N FORCE AND A 5N FORCE ACTS AT THE SAME POINT...
A)WHATS THE GREATEST RESULTANT THAT THESE FORCES CAN PRODUCE????
B)WHATS THE LEAST RESULTANT THAT THE FORCES CAN PRODUCE?????
PLEASE ANSWER...WHO KNOWS IT MIGHT COME IN THE EXAM ;)
Post by: astarmathsandphysics on June 01, 2009, 06:03:50 pm
The effexct is that the input voltage is divided in the ratio of the resitance in the circuit
Post by: astarmathsandphysics on June 01, 2009, 06:08:59 pm
CAN ANY ONE ANSWER THIS QUESTION....ITS FROM MY BOOK..]
IT SAYS
A 12 N FORCE AND A 5N FORCE ACTS AT THE SAME POINT...
A)WHATS THE GREATEST RESULTANT THAT THESE FORCES CAN PRODUCE????
B)WHATS THE LEAST RESULTANT THAT THE FORCES CAN PRODUCE?????
PLEASE ANSWER...WHO KNOWS IT MIGHT COME IN THE EXAM ;)
A0When the act in the same direction R=5+12=17
B)When they act in opposite direction R=12-5=7N
Post by: esso on June 01, 2009, 06:18:05 pm
Post by: Hope on June 01, 2009, 08:54:31 pm
If you notice how we play around with our fingers to get the answer haha; we're actually positioning our fingers on axes..
Fleming's left hand rule says that the third finger is the current, second finger is the magnetic field and the thumb is the force.
Now, we can simply draw axes (including x,y,z) This can be seen in my attachment.
If the magentic field is on the x-axis (denoted as B), current is on the y-axis (denoted as I), then you begin to move from I to B, through the shortest distance between both. In this case, it is clockwise. Any clockwise rotation corresponds to a negative axis. And since the z-axis is the only one that has not been given, it must be on the negative z-axis. In other words, the force is into the page!
I hope I made this as simple as possible. :)
Post by: Hope on June 01, 2009, 09:01:22 pm
Post by: MaNa on June 01, 2009, 09:02:44 pm
from 1993-2002
if so can some one send me on teenangel_MK@hotmail.com
thankyou
Post by: esso on June 01, 2009, 09:06:59 pm
solids which have high specific heat capacity....do they get warm rapidly or take more time to heat up????
nd why???
thanx in advance
Post by: astarmathsandphysics on June 01, 2009, 09:11:17 pm
Post by: studentforumuser on June 02, 2009, 08:46:43 am
So Can Someone plzz Tell me the most important things, you should know,
like things whuch are really important..
Thanks Anyway..!
=D
Post by: frenzy1234 on June 02, 2009, 09:15:37 am
im_gone92@hotmail.com
or just put it up here pls
love u guys <3 :-* :-*
Post by: goin4dakill on June 02, 2009, 10:34:51 am
November 2008.
Question 1dii
PLEASE GUYS I BEG YOU! I do not understand how to get the answer!
Post by: heat619 on June 02, 2009, 11:20:53 am
Mirror
Magnifying Glass
Periscope
thanx in advance
Post by: nitcomp on June 02, 2009, 11:27:25 am
Is the image in the following cases real or virtual?all virtual
Mirror
Magnifying Glass
Periscope
thanx in advance
Post by: IGfab4 on June 02, 2009, 11:44:31 am
sorry...is the absorber (radiation) the same thing as a detector? ???
Post by: studentforumuser on June 02, 2009, 11:57:07 am
So Can Someone plzz Tell me the most important things, you should know, ???
like things whuch are really important..
Thanks Anyway..! :P
=D
does any1 have a summary or any notes etc.... like the one q80boy had given for chemistry..!!
just put it up here pls..! :)
Post by: IGfab4 on June 02, 2009, 12:12:11 pm
i like MUSE...
Post by: Kim on June 02, 2009, 12:30:21 pm
does anyone like rock music? :D if so post your favourite band along your queries....how is this related to physics?
i like MUSE...
anyways cud sum1 tell me how a thermocouple works?
Post by: IGfab4 on June 02, 2009, 12:39:17 pm
anyway, thermocouple works when there are two junctions, hot and cold, connected by two wires of different conducting abilities(usually copper and constaton). the difference in temperature produces a potential difference between the two junctions which can be read on a calibrated voltmeter which shows the temperature. the cold junction is usually melting ice at 0 degrees C.
:D happy studying
Post by: Kim on June 02, 2009, 12:43:01 pm
it's just some kind of a break....wouldn't mind just posting one extra word.. 8)thank you and i didnt mean to be mean if u tuk it dat way den i m sorry!!!!!!!!peace dude
anyway, thermocouple works when there are two junctions, hot and cold, connected by two wires of different conducting abilities(usually copper and constaton). the difference in temperature produces a potential difference between the two junctions which can be read on a calibrated voltmeter which shows the temperature. the cold junction is usually melting ice at 0 degrees C.
:D happy studying
and wats wid the big writtin and bright colours?u hyper or sumthin ;D
Post by: IGfab4 on June 02, 2009, 12:50:04 pm
i never really like size 10. text must always be something that people can read easily :)
love the electricity part in physics...mostly easy :D
Post by: IGfab4 on June 02, 2009, 01:04:50 pm
sorry...is the absorber (radiation) the same thing as a detector? ???
does anyone know this???????? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ???
Post by: Diablo on June 02, 2009, 01:18:27 pm
Does anyone know where I can find the mark scheme/answer guide for May / June 2001 session for Physics Paper 3?
Thanks :)
Post by: IGfab4 on June 02, 2009, 01:23:43 pm
Hello,
Does anyone know where I can find the mark scheme/answer guide for May / June 2001 session for Physics Paper 3?
Thanks :)
i do not know if freeexampapers.com or any other website has it.... because all papers are from winter 2002 :-\
Post by: IGfab4 on June 02, 2009, 01:26:44 pm
Hello,
Does anyone know where I can find the mark scheme/answer guide for May / June 2001 session for Physics Paper 3?
Thanks :)
which question do you need to check because i've done the paper... ;)
Post by: Diablo on June 02, 2009, 01:34:11 pm
I have done it too, but I want to make sure of my answers. Kindly, can you post the answers for Question 8 (a) - (c)Hello,
Does anyone know where I can find the mark scheme/answer guide for May / June 2001 session for Physics Paper 3?
Thanks :)
which question do you need to check because i've done the paper... ;)
Post by: IGfab4 on June 02, 2009, 01:38:43 pm
I have done it too, but I want to make sure of my answers. Kindly, can you post the answers for Question 8 (a) - (c)Hello,
Does anyone know where I can find the mark scheme/answer guide for May / June 2001 session for Physics Paper 3?
Thanks :)
which question do you need to check because i've done the paper... ;)
8 a
1) 0.4 A
2) 3.75 ohms
3) 8C
b
1) connect in parallel
2) connect in series
c
36 J
that's it!! :D the diagrams use part b to complete, stating the length too!! ;D
Post by: Diablo on June 02, 2009, 01:46:25 pm
Post by: IGCSE nightmare on June 02, 2009, 01:48:01 pm
should we draw wavefronts or what?
Post by: zara on June 02, 2009, 01:53:18 pm
Post by: IGfab4 on June 02, 2009, 01:55:32 pm
I am wondering what should we draw when they ask us to draw a 'sound wave' with compressions and rarefactions?
should we draw wavefronts or what?
kk i'll also use smaller font but still not 10!! :D :D
for sound waves , i think we have to draw normal waves with the crests labelled compression and troughs named rarefaction :P
Post by: IGCSE nightmare on June 02, 2009, 02:04:09 pm
Because I thought we can draw many waves close together naming them a compression and many other quite apart and name them a rarefaction?
Post by: IGfab4 on June 02, 2009, 02:07:38 pm
Then the y-axis will be 'air pressure' ?! Isn't it?
Because I thought we can draw many waves close together naming them a compression and many other quite apart and name them a rarefaction?
yeah, but the y-axis will be air pressure and labelled above normal, normal, and below normal. as high air pressure is caused by compression and low air pressure by rarefaction :D
Post by: idol2009 on June 02, 2009, 02:23:18 pm
If anyone could explain to me that would be really helpful!
Post by: simply.me on June 02, 2009, 02:27:02 pm
or send it to my email ms_bueaty@hotmail.com
Post by: IGfab4 on June 02, 2009, 02:36:45 pm
The refractive index is sin i/sin r if I am not mistaken, so why in the Oct/Nov 08 paper 3 mark scheme is the answer to question 6b) sin r /sin i? I can't seem to understand, even though the answer looks wrong...
If anyone could explain to me that would be really helpful!
see you always calculate sin i / sin r when a light ray passes from rarer medium to a denser medium. but at that instant, you should calculate using sin r / sin i because it's the other way round..... the ray inside the denser medium is going to pass out to the rarer medium. :D
and By the way, simply.me , i sent you m/j 08 marksheme.. :) :)
Post by: idol2009 on June 02, 2009, 02:38:33 pm
Post by: IGfab4 on June 02, 2009, 02:41:02 pm
Quote from: idol2009 link=topic=1798.msg34881#msg34881 date=12[size=10pt
[/size]43949913]
Oh..okay! thanks..that was me not thinking straight!
hehe don't worry, it's the result of too many exams..... By the way way you forgot +rep :D
Post by: lana on June 02, 2009, 03:16:32 pm
thanks =]
Post by: goin4dakill on June 02, 2009, 03:21:39 pm
I really am freaking out right now..
I have done very few past papers...and i did fine. I mean i got an A on the mock- good enough!
I just did the latest exam... Nov 2008.
IT WAS SO HARD! AND JUST LIKE CHEM IM SCARED ITS GUNNA BE THE SAME!!!!!!! Seriously, what do you guys tihnk..and am I the only one that thinks this paper is hard??
Post by: IGfab4 on June 02, 2009, 03:34:38 pm
hey i cant solve Q3 in m/j/03 can someone please help me ??
thanks =]
this is the answer to the question 3 of '03 may june
just use a compass and protractor. draw the big base using a scale of 1:100 and then use your compass. ;) ;)
Post by: Bani on June 02, 2009, 03:36:18 pm
Thanks in advance.
Post by: lana on June 02, 2009, 03:37:48 pm
+rep for you and i'll +rep u again after 2 hours !!!
Post by: IGfab4 on June 02, 2009, 03:39:08 pm
Guysss!
I really am freaking out right now..
I have done very few past papers...and i did fine. I mean i got an A on the mock- good enough!
I just did the latest exam... Nov 2008.
IT WAS SO HARD! AND JUST LIKE CHEM IM SCARED ITS GUNNA BE THE SAME!!!!!!! Seriously, what do you guys tihnk..and am I the only one that thinks this paper is hard??
hey there goin4dakill!! you'll be fine because:
1) if you know how to answer - you can score
2) you said you got an A in the hard mock - no need for panic
3) the threshold is low for p3 , usually being 55% ;D
remember Bob Marley "Don't worry! Be happy"
Post by: IGfab4 on June 02, 2009, 03:40:05 pm
thank you so much your great !! =]
+rep for you and i'll +rep u again after 2 hours !!!
+rep 4 you too!! :D
Post by: lana on June 02, 2009, 03:41:03 pm
Post by: goin4dakill on June 02, 2009, 03:41:51 pm
Guysss!
I really am freaking out right now..
I have done very few past papers...and i did fine. I mean i got an A on the mock- good enough!
I just did the latest exam... Nov 2008.
IT WAS SO HARD! AND JUST LIKE CHEM IM SCARED ITS GUNNA BE THE SAME!!!!!!! Seriously, what do you guys tihnk..and am I the only one that thinks this paper is hard??
hey there goin4dakill!! you'll be fine because:
1) if you know how to answer - you can score
2) you said you got an A in the hard mock - no need for panic
3) the threshold is low for p3 , usually being 55% ;D
remember Bob Marley "Don't worry! Be happy"
Hey :)))
Thank you, I really appreciate that :)
Rep + for you luv
Post by: IGfab4 on June 02, 2009, 03:53:01 pm
Hey guys!!! I need help. Paper 3, May/June 2007, Q9 b) and c) . Could you please attach the drawings for these both...Pleaseee
Thanks in advance.
and for the b part.....it's upwards so the wheel turns in the anti-clockwise direction. hope this helps!! ;D
Post by: Mirzaa on June 02, 2009, 04:00:29 pm
hehe i didn't mean that.. lol
i never really like size 10. text must always be something that people can read easily :)
love the electricity part in physics...mostly easy :D
damn u find it easy?? radiations prolly easiest, i use to finde this hard cause my shitty "teacher" cant teach, so i usesd the revision guide...which i now find kinda easy..
Post by: IGfab4 on June 02, 2009, 04:00:51 pm
Guysss!
I really am freaking out right now..
I have done very few past papers...and i did fine. I mean i got an A on the mock- good enough!
I just did the latest exam... Nov 2008.
IT WAS SO HARD! AND JUST LIKE CHEM IM SCARED ITS GUNNA BE THE SAME!!!!!!! Seriously, what do you guys tihnk..and am I the only one that thinks this paper is hard??
hey there goin4dakill!! you'll be fine because:
1) if you know how to answer - you can score
2) you said you got an A in the hard mock - no need for panic
3) the threshold is low for p3 , usually being 55% ;D
remember Bob Marley "Don't worry! Be happy"
Hey :)))
Thank you, I really appreciate that :)
Rep + for you luv
+rep for you too!! ::) :D :D :D
Post by: unknown on June 02, 2009, 04:06:40 pm
Post by: Shogun on June 02, 2009, 04:08:43 pm
it would be like this..
Post by: IGfab4 on June 02, 2009, 04:16:26 pm
alright for the question asked how u could draw a sound wave with compression and rarefractions. and NO its not like water wave and instead crest u put rarefraction...
it would be like this..
oh thanks!! this would be good!! :D
Post by: Bani on June 02, 2009, 04:21:41 pm
Hey guys!!! I need help. Paper 3, May/June 2007, Q9 b) and c) . Could you please attach the drawings for these both...Pleaseee
Thanks in advance.
and for the b part.....it's upwards so the wheel turns in the anti-clockwise direction. hope this helps!! ;D
Thanks a lot ! + rep for you ;D and could you please tell me that for part b), how do we work out its upwards? Using left hand rule, the first finger points from left to right (North to South), and the second finger points where? ( i know tht second finger is for current) and thumb is for the movement. Thanks in advance :)
Post by: unknown on June 02, 2009, 04:22:57 pm
Post by: IGfab4 on June 02, 2009, 04:25:54 pm
Hey guys!!! I need help. Paper 3, May/June 2007, Q9 b) and c) . Could you please attach the drawings for these both...Pleaseee
Thanks in advance.
and for the b part.....it's upwards so the wheel turns in the anti-clockwise direction. hope this helps!! ;D
Thanks a lot ! + rep for you ;D and could you please tell me that for part b), how do we work out its upwards? Using left hand rule, the first finger points from left to right (North to South), and the second finger points where? ( i know tht second finger is for current) and thumb is for the movement. Thanks in advance :)
Post by: Shogun on June 02, 2009, 04:26:42 pm
alright for the question asked how u could draw a sound wave with compression and rarefractions. and NO its not like water wave and instead crest u put rarefraction...
it would be like this..
oh thanks!! this would be good!! :D
ure welcome
Post by: goin4dakill on June 02, 2009, 04:26:54 pm
How do you know when to use them
2)What on earth is the difference between..ahem
-latent heat of fusion
-specific heat of fusion
-specific latent heat
-heat capacity
-linear expansivity
ConFUsIoooN
???
Thank you guyssss
I bid u good luck ;)
Post by: unknown on June 02, 2009, 04:32:33 pm
n ya u use l.h fr motors n r.h fr generators
n latent heat fusion is fr like solid 2 liquid n vice versa nvapourisation is fr gas 2 liquid n vice versa
remember no change in temp takes place
s.h.c is d amount og energy required to raise d temperature of 1kg by 1 degree celsius nt 2 sure of this part
hope i helped
nw plz can somone help me
Post by: IGfab4 on June 02, 2009, 04:36:26 pm
hey need help in 08 nov 1Q b part first variant actually d whole q n also cld neone explain me d 9a ans 2 i cant get it
1)B) there is a force(weight actually) acting on the trolley (which is an unbalanced force) which shows that force is directly proportional to acceleration when mass is constant.
and electrical energy is transmitted using high voltage to prevent power loss(and to reduce the current) as an increase in current would result in heat loss.
Post by: Shogun on June 02, 2009, 04:37:59 pm
hoever on a normal coil or the generator producing kinetic energy (movement) from elctricity(i.e DC motor)
then use flemings left hand rule. however to find out direction of current or deflection of radiations or wire, use left hand rule.
latent heat of fusion is the hidden temp or the stationary temp at which melting takes place where ice literally (i mean really literally) changes to liquid.
specific heat of fusion is the amount of heat need to do such phenomena as i discussed above. (but really i did no see this included in any of the paper 3 physics)
specific heat capacity is the heant needed to rase 1 degree temp for 1 kg of substance.whereas heat capcity means the whole body it self (i.e the heat needed to raise 1 degree of temp of the whole body.)
notice tht 1 killo is not added in this explanation for heat capacity.
linear expansivity means sunstance expanding with same distance between the degrees calbrited on the thermometor at the same interval. or in short, same distance expanded between all degree interval.
Post by: unknown on June 02, 2009, 04:43:49 pm
bt y 2 pump water to higher level storage n ya hmm can u solve d whole q 1hey need help in 08 nov 1Q b part first variant actually d whole q n also cld neone explain me d 9a ans 2 i cant get it
1)B) there is a force(weight actually) acting on the trolley (which is an unbalanced force) which shows that force is directly proportional to acceleration when mass is constant.
and electrical energy is transmitted using high voltage to prevent power loss(and to reduce the current) as an increase in current would result in heat loss.
Post by: IGfab4 on June 02, 2009, 04:47:38 pm
bt y 2 pump water to higher level storage n ya hmm can u solve d whole q 1hey need help in 08 nov 1Q b part first variant actually d whole q n also cld neone explain me d 9a ans 2 i cant get it
1)B) there is a force(weight actually) acting on the trolley (which is an unbalanced force) which shows that force is directly proportional to acceleration when mass is constant.
and electrical energy is transmitted using high voltage to prevent power loss(and to reduce the current) as an increase in current would result in heat loss.
if you store water at ahigh level, then you will have a high gravitational potential energy and can later be used to convert to KE to turn turbines and produce electricity...
Post by: goin4dakill on June 02, 2009, 05:12:06 pm
alright. use right hand flemings rule on something tht generates electricity (ie the the AC generator)
hoever on a normal coil or the generator producing kinetic energy (movement) from elctricity(i.e DC motor)
then use flemings left hand rule. however to find out direction of current or deflection of radiations or wire, use left hand rule.
latent heat of fusion is the hidden temp or the stationary temp at which melting takes place where ice literally (i mean really literally) changes to liquid.
specific heat of fusion is the amount of heat need to do such phenomena as i discussed above. (but really i did no see this included in any of the paper 3 physics)
specific heat capacity is the heant needed to rase 1 degree temp for 1 kg of substance.whereas heat capcity means the whole body it self (i.e the heat needed to raise 1 degree of temp of the whole body.)
notice tht 1 killo is not added in this explanation for heat capacity.
linear expansivity means sunstance expanding with same distance between the degrees calbrited on the thermometor at the same interval. or in short, same distance expanded between all degree interval.
Hey, thanks alot!
umm, well specific heat of fusion..is actually on paper 3- June november :/ Thats why I was wondering..
And i didnt know the equation for it. Im so sorry, one more question.
E= Slf * m
E= m *C * temp change
x= al* temp change (x being increasing length, a being linear expansivity and L bring original length.
Is that all I need to know??
+ rep for u, once i get over the karma thingamabob..in a few minutes i should be able to. :D
Post by: Shogun on June 02, 2009, 05:20:38 pm
but do stress onE=mlf and mlv
E= m *C * temp change
most question come based on these..
Post by: simply.me on June 02, 2009, 05:33:21 pm
i need to now how to draw the diagram .. m/j 2008 Q.8a
Post by: goin4dakill on June 02, 2009, 05:35:48 pm
yup thts all. ;D
but do stress onE=mlf and mlv
E= m *C * temp change
most question come based on these..
What is mlv??
Post by: Alk on June 02, 2009, 05:38:08 pm
and i also need someone to explain lenz law!
Thanks
Post by: Shogun on June 02, 2009, 05:39:17 pm
yup thts all. ;D
but do stress onE=mlf and mlv
E= m *C * temp change
most question come based on these..
What is mlv??
its for latent heat of vapourisation..
Post by: astarmathsandphysics on June 02, 2009, 06:13:43 pm
is the DC generator included ? and if yes plzz i need someone to explain it to me..
and i also need someone to explain lenz law!
Thanks
A coil of wire rotating in a magnetic field has a current induced in it. Every time the loop completels a half turn the direction of the current in the loop changes but the loop makes contact with a commutator, and the points of contact also change every half turn so the direction of the current as it exits the generator is unchanged
http://www.koehler.me.uk/animation/e_and_m_dc_gen_1.htm
Post by: astarmathsandphysics on June 02, 2009, 06:18:42 pm
can ne1 .. explain about logic gates n how to draw them ..
i need to now how to draw the diagram .. m/j 2008 Q.8a
all you need
http://en.wikipedia.org/wiki/Logic_gate
Post by: astarmathsandphysics on June 02, 2009, 06:20:38 pm
Post by: ny on June 02, 2009, 06:25:54 pm
Post by: astarmathsandphysics on June 02, 2009, 06:36:14 pm
fission is what happens in atom bombs eg 236U>141Ba+92Kr+31n atoms split to make smaller atoms
Post by: Shogun on June 02, 2009, 06:37:01 pm
Post by: ny on June 02, 2009, 06:41:51 pm
nuclear fusion is what happens to make stars shine eg 4p1+>He2++2e+ atoms fuse to make bigger atoms
fission is what happens in atom bombs eg 236U>141Ba+92Kr+31n atoms split to make smaller atoms
okay.thanks. ;)
Post by: nid404 on June 02, 2009, 06:46:35 pm
superb ppt attached check it out
Post by: Shogun on June 02, 2009, 06:49:13 pm
Post by: nid404 on June 02, 2009, 06:50:48 pm
but yes for eco and bio i do
Post by: Shogun on June 02, 2009, 07:00:06 pm
Post by: islu_jf on June 02, 2009, 07:47:59 pm
Post by: 12345abc on June 02, 2009, 09:36:48 pm
thick or thin AND should expand little/more when heated???
plz explain as well
Post by: ***-))((-S.U.B-))((-*** on June 02, 2009, 10:12:08 pm
-state and use the symbols for logic gates
(the American ANSI#Y 32.14 symbols will be used)
Its a line from the syllabus
Post by: idol2009 on June 03, 2009, 05:11:31 am
I usually find this pretty straightforward, but on this problem I was kind of stuck, because my answer didn't match the mark scheme...
The question goes as follows:
"Using a 40W heater, 16.3 g of ice is melted in 2.0 minutes. The heater is then switched off. In a further 2.0 minutes, 2.1 g of ice is melted.
Calculate the specific latent heat of fusion of ice from these results."
So I basically did the following calculation:
Total Energy supplied = 40 x 120 = 4800 J
Total Mass melted by heater = 16.3 g
Specific latent heat = 4800/16.3 = 294.5 J/g
I don't understand what I've done wrong, and what the switching the heater off and the further 2 mins has to do with it?
Any help would be appreciated thanks!
Post by: Friends on June 03, 2009, 06:08:40 am
Like force-NEWTON
Post by: Q80BOY on June 03, 2009, 07:32:14 am
quantity - unit - symbol
Mass - Kilogram - Kg
Length - Metre - m
Time - Second - s
Area - Square metre - m^2
Volume - Cubic metre - m^3
Force - Newton - N
Weight - Newton - N
Pressure - Pascal - Pa
Energy - Joule - J
Work - Joule - J
Power - Watt - W
Frequency - Hertz - Hz
PD, EMF, Voltage - Volt - V
Current - Ampere - A
Resistance - Ohm - _()_ <-- thats the ohm sign :P
Charge - Coulomb - C
Temperature - Kelvin - K
Temperature - degrees Celcius - *C
hope this helps :)
Post by: Friends on June 03, 2009, 07:36:38 am
+ rep for u
Post by: Q80BOY on June 03, 2009, 07:40:54 am
Thanx man
+ rep for u
Thanks :)
Post by: IGSTUDENT on June 03, 2009, 07:42:35 am
some1 wanted help wid lenz's law..im really bad at explaining physicsDo we need to cover this lenz law?
superb ppt attached check it out
Post by: IGSTUDENT on June 03, 2009, 07:45:05 am
Post by: Q80BOY on June 03, 2009, 07:46:11 am
some1 wanted help wid lenz's law..im really bad at explaining physicsDo we need to cover this lenz law?
superb ppt attached check it out
ya, its important, didnt u do electromagnetism ??
Post by: nid404 on June 03, 2009, 07:46:19 am
some1 wanted help wid lenz's law..im really bad at explaining physicsDo we need to cover this lenz law?
superb ppt attached check it out
we do have electromagnetic induction.....and so yeah we gotta cover lenz's law
Post by: nid404 on June 03, 2009, 07:49:33 am
Post by: Q80BOY on June 03, 2009, 07:51:11 am
and here's w8 u should look at before leaving ur house for the physics paper.
thanks a lot ;)
+REP
Post by: Friends on June 03, 2009, 08:03:56 am
n = sinr/sini OR n = sini/sinr in any form
1.33 = sinr/sin40 OR sinr = 1.33 × sin40
Any value between 58.68° – 60° inclusive
This is from mark scheme but still i dont get answers.
Anuone plzzz help
Post by: Q80BOY on June 03, 2009, 08:07:39 am
Find Sine R,
so, 1.33 x Sine 40
use ur calculator for the answer, it should be in the range 58.68 - 60
hope this helps :)
Post by: VIP_93 on June 03, 2009, 08:11:24 am
thx in advance
Post by: Q80BOY on June 03, 2009, 08:14:19 am
can i plz have da mark scheme of jun-nov 2000 and jun 2001
thx in advance
they're on scribid @ this link : www.scribd.com/doc/3183763/Physics-Answers-1993-2002
hope this helps :)
Post by: Ibiza279 on June 03, 2009, 09:24:03 am
n wats lenz law again ? :D
Post by: Friends on June 03, 2009, 09:38:07 am
I am totally lost.
By the way Thanks Q80BOY. I totally forgot to do sin inverse.
Post by: Ibiza279 on June 03, 2009, 09:40:04 am
Post by: Friends on June 03, 2009, 09:42:31 am
sure wat are ur questions bout waves ?I am totally lost. I need to know pattern of waves in water when they pass thru a gap.
Post by: SGVaibhav on June 03, 2009, 09:49:22 am
one is displacement/time and the other is displacement/lenth.
can anyone elaborate more about these two types of graphs.
Post by: Ibiza279 on June 03, 2009, 09:52:01 am
when water waves pass thru a gap, if the gap's length is equal to the wave's wavelength then there will b a spherical diffraction,
but if the wavelength of the wave is lower than the gap of the length then the waves formed will hav defraction on their extreme edges, they will look like straight lines that are bent on the edges.
we don't hav the diffraction of waves such that the length of the gap is smaller than the length of the wavelength.
remember the top two points all the best
Post by: Shogun on June 03, 2009, 09:55:54 am
if size of gap is the same size of wavelength (u gotta measure them with ure scale or the giv u this info on the question): the wave will pass through the gap with a circular pattern.
if size of gap is bigger than the wavelength of the wave: the wave should pass throught in a wide wave around the ages pattern.
it would go like this:
but be sure tht ure wave (outside the gap) must have the dame wave legnth as the wave before the gap, cuz wave length doesnot change , speed does not change, frequency does not change, only direction changes
hope his helps..
Post by: Friends on June 03, 2009, 09:56:11 am
ok its simple
when water waves pass thru a gap, if the gap's length is equal to the wave's wavelength then there will b a spherical diffraction,
but if the wavelength of the wave is lower than the gap of the length then the waves formed will hav defraction on their extreme edges, they will look like straight lines that are bent on the edges.
we don't hav the diffraction of waves such that the length of the gap is smaller than the length of the wavelength.
remember the top two points all the best
Ok I got it.thanx man
+rep
Thanx Shogun
Post by: Ibiza279 on June 03, 2009, 09:58:11 am
guys i was taught there are two types of sound graphs u need to know
one is displacement/time and the other is displacement/lenth.
can anyone elaborate more about these two types of graphs.
hey call them speed/time and distance/time graph, thats much more easier to understand
as fer the speed time graph, area under the graph gives u the distance travelled.
the distance time graph jus tells u if the cars on constant speed or accelerating etc.
i guess thats all about it.
but be sure to memorise the three velocity formulas
they r
v=u+at
v^2=u^2 + 2as
s = ut + 1/2at^2
where " s " is the displacement
do counter check with ur books or online sources if they r correct :D lol
Post by: esso on June 03, 2009, 09:58:23 am
a bit difficult...
thanx in advance
Post by: Ibiza279 on June 03, 2009, 10:01:43 am
Post by: Shogun on June 03, 2009, 10:02:24 am
Post by: idol2009 on June 03, 2009, 10:12:39 am
Hey, I was doing the Oct/Nov 08 Paper 3, and on question 5c), it asks you to calculate the specific latent hear of fusion of ice from the results they have given you...
I usually find this pretty straightforward, but on this problem I was kind of stuck, because my answer didn't match the mark scheme...
The question goes as follows:
"Using a 40W heater, 16.3 g of ice is melted in 2.0 minutes. The heater is then switched off. In a further 2.0 minutes, 2.1 g of ice is melted.
Calculate the specific latent heat of fusion of ice from these results."
So I basically did the following calculation:
Total Energy supplied = 40 x 120 = 4800 J
Total Mass melted by heater = 16.3 g
Specific latent heat = 4800/16.3 = 294.5 J/g
I don't understand what I've done wrong, and what the switching the heater off and the further 2 mins has to do with it?
Any help would be appreciated thanks!
Post by: VIP_93 on June 03, 2009, 10:13:23 am
thanx alot Q80BOY
Post by: Enia on June 03, 2009, 10:15:49 am
Can you please explain to be how to predict the direction of alpha, Beta, and gamma radiations in a magnetic field? Thank you :D
Post by: Shogun on June 03, 2009, 10:18:33 am
Since no one answered my question before, i will repost it =)
Hey, I was doing the Oct/Nov 08 Paper 3, and on question 5c), it asks you to calculate the specific latent hear of fusion of ice from the results they have given you...
I usually find this pretty straightforward, but on this problem I was kind of stuck, because my answer didn't match the mark scheme...
The question goes as follows:
"Using a 40W heater, 16.3 g of ice is melted in 2.0 minutes. The heater is then switched off. In a further 2.0 minutes, 2.1 g of ice is melted.
Calculate the specific latent heat of fusion of ice from these results."
So I basically did the following calculation:
Total Energy supplied = 40 x 120 = 4800 J
Total Mass melted by heater = 16.3 g
Specific latent heat = 4800/16.3 = 294.5 J/g
I don't understand what I've done wrong, and what the switching the heater off and the further 2 mins has to do with it?
Any help would be appreciated thanks!
oh sorry for u answer to be delayed, so ill try to help u out right away.. ;D
Post by: IGSTUDENT on June 03, 2009, 10:21:26 am
Since no one answered my question before, i will repost it =)
Hey, I was doing the Oct/Nov 08 Paper 3, and on question 5c), it asks you to calculate the specific latent hear of fusion of ice from the results they have given you...
I usually find this pretty straightforward, but on this problem I was kind of stuck, because my answer didn't match the mark scheme...
The question goes as follows:
"Using a 40W heater, 16.3 g of ice is melted in 2.0 minutes. The heater is then switched off. In a further 2.0 minutes, 2.1 g of ice is melted.
Calculate the specific latent heat of fusion of ice from these results."
So I basically did the following calculation:
Total Energy supplied = 40 x 120 = 4800 J
Total Mass melted by heater = 16.3 g
Specific latent heat = 4800/16.3 = 294.5 J/g
I don't understand what I've done wrong, and what the switching the heater off and the further 2 mins has to do with it?
Any help would be appreciated thanks!
oh sorry for u answer to be delayed, so ill try to help u out right away.. ;D
SHOGUN
R u a student or a teacher? U seem to have an answer for every problem.And time to solve every query 8)
Post by: Ibiza279 on June 03, 2009, 10:22:38 am
Since no one answered my question before, i will repost it =)
Hey, I was doing the Oct/Nov 08 Paper 3, and on question 5c), it asks you to calculate the specific latent hear of fusion of ice from the results they have given you...
I usually find this pretty straightforward, but on this problem I was kind of stuck, because my answer didn't match the mark scheme...
The question goes as follows:
"Using a 40W heater, 16.3 g of ice is melted in 2.0 minutes. The heater is then switched off. In a further 2.0 minutes, 2.1 g of ice is melted.
Calculate the specific latent heat of fusion of ice from these results."
So I basically did the following calculation:
Total Energy supplied = 40 x 120 = 4800 J
Total Mass melted by heater = 16.3 g
Specific latent heat = 4800/16.3 = 294.5 J/g
I don't understand what I've done wrong, and what the switching the heater off and the further 2 mins has to do with it?
Any help would be appreciated thanks!
what answer does the mark scheme tell u ?
Post by: Shogun on June 03, 2009, 10:23:26 am
Hi! I had another tiny question (and probably a lot more as I do last minute revision so plz be patient with me).
Can you please explain to be how to predict the direction of alpha, Beta, and gamma radiations in a magnetic field? Thank you :D
deflections of rays in magnetic fields
alpha is positively charged so in magnetic field in to the paper (the north pole faced towards a paper) (uding flemings left hand u point ure index finger just like the way u would point at somone and with the thumb up and ure middle finger pointing towards the right(which is the direction alpha rays)) so doing this would indicate tht alpha rays deflects upwards.
however the beta rays(negatively charges) moves opposite to the deflection of alpha rays (i.e downwards but with the same conditions set as experssed for the alpha rays)
whereas in gamma rays, no deflection in magntic field.
deflections of rays in an electrical field.
lets say there are 2 charged plates place over another(with gap inbetwwen), one is postively charged plate which is for example the upper plate, and the lower plate is negatively charged. alpha rays deflect yowards the negative side (i.e downwards) as it is postively charged, whereas the beta rays deflects towards the positively charge plate(i.e upwards, just opposite of alpha rays). gamma rays do not deflect in electric fields either.
hope this helped, any confusion difficulties or help needed, plz do ask me
Post by: Ibiza279 on June 03, 2009, 10:23:57 am
Since no one answered my question before, i will repost it =)
Hey, I was doing the Oct/Nov 08 Paper 3, and on question 5c), it asks you to calculate the specific latent hear of fusion of ice from the results they have given you...
I usually find this pretty straightforward, but on this problem I was kind of stuck, because my answer didn't match the mark scheme...
The question goes as follows:
"Using a 40W heater, 16.3 g of ice is melted in 2.0 minutes. The heater is then switched off. In a further 2.0 minutes, 2.1 g of ice is melted.
Calculate the specific latent heat of fusion of ice from these results."
So I basically did the following calculation:
Total Energy supplied = 40 x 120 = 4800 J
Total Mass melted by heater = 16.3 g
Specific latent heat = 4800/16.3 = 294.5 J/g
I don't understand what I've done wrong, and what the switching the heater off and the further 2 mins has to do with it?
Any help would be appreciated thanks!
oh sorry for u answer to be delayed, so ill try to help u out right away.. ;D
SHOGUN
R u a student or a teacher? U seem to have an answer for every problem.And time to solve every query 8)
hey who cares atleast he tells us the answer to the questions n clears our doubts i mean if hes a teacher v thnk him, if hes a student we still thnk him
so thnk u shogun :)
Post by: IGSTUDENT on June 03, 2009, 10:24:41 am
R u a teacher or a student/
Where are u giving your exams from?
Post by: Shogun on June 03, 2009, 10:26:42 am
Since no one answered my question before, i will repost it =)
Hey, I was doing the Oct/Nov 08 Paper 3, and on question 5c), it asks you to calculate the specific latent hear of fusion of ice from the results they have given you...
I usually find this pretty straightforward, but on this problem I was kind of stuck, because my answer didn't match the mark scheme...
The question goes as follows:
"Using a 40W heater, 16.3 g of ice is melted in 2.0 minutes. The heater is then switched off. In a further 2.0 minutes, 2.1 g of ice is melted.
Calculate the specific latent heat of fusion of ice from these results."
So I basically did the following calculation:
Total Energy supplied = 40 x 120 = 4800 J
Total Mass melted by heater = 16.3 g
Specific latent heat = 4800/16.3 = 294.5 J/g
I don't understand what I've done wrong, and what the switching the heater off and the further 2 mins has to do with it?
Any help would be appreciated thanks!
oh sorry for u answer to be delayed, so ill try to help u out right away.. ;D
SHOGUN
R u a student or a teacher? U seem to have an answer for every problem.And time to solve every query 8)
lol im no teacher im a student and i take ig subject its just tht physics is my subject and if i learn something new, id go deep into it even though it was to be studied by students in the universeties.. i daily go to my phsyics to leran something thts out of the syllabus.. ;D
i live in bahrain, and i take exams from cie in ma school.
Post by: Ghost Of Highbury on June 03, 2009, 10:30:10 am
40W --> 40 J/s for 180 seconds = 7200J
7200 = 250 * 5.9 * c
7200/ 1475 = 4.88
ans = 4.88 J/g degree celcius
oct/noc 2008 second variant 5c
Post by: Ibiza279 on June 03, 2009, 10:34:11 am
they r askin fer the latent heat not the specific latent heat of water
so u just use the equation E=ml
n somebody give me the answer to this question from the answer sheet cause i think the mass v hav to use is 2.1 g n not 16.3g "Using a 40W heater, 16.3 g of ice is melted in 2.0 minutes. The heater is then switched off. In a further 2.0 minutes, 2.1 g of ice is melted.
Calculate the specific latent heat of fusion of ice from these results."
Post by: Shogun on June 03, 2009, 10:35:10 am
u need the mass taken for the ice to melt completely, ie. initial mass of ice melted is 16.3, final mass of ice melted is 2.1... so to get the actuall mass tht was melted u have to subtract
i.e 16.3-2.1=14.2g
then use the formula P x t= mlf
40 x 120 = 14.2 x m (we need to find m)
then sunsitute the equation to : (40 x 120) / 14.2
u get 338j/g which will be ure "M",
do check the mark scheme if its correct....
Post by: Shogun on June 03, 2009, 10:37:29 am
Post by: Enia on June 03, 2009, 10:37:36 am
Post by: Shogun on June 03, 2009, 10:38:45 am
Post by: Ghost Of Highbury on June 03, 2009, 10:39:53 am
hah..
Post by: Ibiza279 on June 03, 2009, 10:41:09 am
allright, see u have taken the whole mass not the mass of ice which is actually bieng melted, so its not 16.3
u need the mass taken for the ice to melt completely, ie. initial mass of ice melted is 16.3, final mass of ice melted is 2.1... so to get the actuall mass tht was melted u have to subtract
i.e 16.3-2.1=14.2g
then use the formula P x t= mlf
40 x 120 = 14.2 x m (we need to find m)
then sunsitute the equation to : (40 x 120) / 14.2
u get 338j/g which will be ure "M",
do check the mark scheme if its correct....
wo wo wo wo hold up
16.3 is the mass of ice that melted on heating and 2.1 is the mass of ice melted when there was no heat supplied meaning that the ice melted while it absorbed the heat frm the surrounding so i don't get the point of it
n By the way which year paper question is this one ?
Post by: Ghost Of Highbury on June 03, 2009, 10:44:55 am
allright, see u have taken the whole mass not the mass of ice which is actually bieng melted, so its not 16.3
u need the mass taken for the ice to melt completely, ie. initial mass of ice melted is 16.3, final mass of ice melted is 2.1... so to get the actuall mass tht was melted u have to subtract
i.e 16.3-2.1=14.2g
then use the formula P x t= mlf
40 x 120 = 14.2 x m (we need to find m)
then sunsitute the equation to : (40 x 120) / 14.2
u get 338j/g which will be ure "M",
do check the mark scheme if its correct....
wo wo wo wo hold up
16.3 is the mass of ice that melted on heating and 2.1 is the mass of ice melted when there was no heat supplied meaning that the ice melted while it absorbed the heat frm the surrounding so i don't get the point of it
n By the way which year paper question is this one ?
i am confused too...
why do u need to subtract
?
Post by: Ghost Of Highbury on June 03, 2009, 10:45:32 am
Post by: Shogun on June 03, 2009, 10:45:46 am
so 16.3 and 2.1 are not the mass melted by heater...
the one melted from heater is when 2.1 was melted from the 16.3
Post by: Ghost Of Highbury on June 03, 2009, 10:48:21 am
after that how can more 2.1 g melt from that melted portion
confused
plzz help shogun
Post by: astarmathsandphysics on June 03, 2009, 10:49:16 am
Since no one answered my question before, i will repost it =)
Hey, I was doing the Oct/Nov 08 Paper 3, and on question 5c), it asks you to calculate the specific latent hear of fusion of ice from the results they have given you...
I usually find this pretty straightforward, but on this problem I was kind of stuck, because my answer didn't match the mark scheme...
The question goes as follows:
"Using a 40W heater, 16.3 g of ice is melted in 2.0 minutes. The heater is then switched off. In a further 2.0 minutes, 2.1 g of ice is melted.
Calculate the specific latent heat of fusion of ice from these results."
So I basically did the following calculation:
Total Energy supplied = 40 x 120 = 4800 J
Total Mass melted by heater = 16.3 g
Specific latent heat = 4800/16.3 = 294.5 J/g
I don't understand what I've done wrong, and what the switching the heater off and the further 2 mins has to do with it?
Any help would be appreciated thanks!
The answer is here.
https://studentforums.biz/index.php/topic,1798.msg27218/topicseen.html#msg27218
Post by: IGSTUDENT on June 03, 2009, 10:49:40 am
what are u planning to pursue..astrophysics? or is it chem ,,u are a master in that too
Post by: Shogun on June 03, 2009, 10:50:18 am
16.3 (heat from heater +heat from surrounding) - 2.1(heat from surrounding) = 14.2 (heat from hetaer)
is tht easier...
Post by: Ibiza279 on June 03, 2009, 10:50:24 am
u are correct but see, 16.3g was melted, and from tht 2.1 melted after the heating
so 16.3 and 2.1 are not the mass melted by heater...
the one melted from heater is when 2.1 was melted from the 16.3
wo wo wo it clearly says that 16.3 is melted when the heater is on then furthermore 2.1 g is melted AFTER the heater is off meaning the 2.1 g is the ice melted after the heater was turned off
it doesn't say that a total of 16.3 g of ice is melted man im getting tangled up in this question
Post by: Ghost Of Highbury on June 03, 2009, 10:51:24 am
but the doubt is that why do v have to subtract 16.3 and 2.1???
its clearly says that when 16.3g was melted...the heater was switched on..
thatsy we assume that there is no heat from the surounding..
??
v have to do this for all experiments right??
Post by: astarmathsandphysics on June 03, 2009, 10:52:47 am
Hi! I had another tiny question (and probably a lot more as I do last minute revision so plz be patient with me).
Can you please explain to be how to predict the direction of alpha, Beta, and gamma radiations in a magnetic field? Thank you :D
gamma will be undeflected. Alpha and beta twill be deflected in opposite directions because they are oppositely charged. r=mv/bq so probably the alpha particle will be deflected less but you can also use the left hand rule to find which is whixch
Post by: Ibiza279 on June 03, 2009, 10:53:56 am
alright let see hopw can i expalin
16.3 (heat from heater +heat from surrounding) - 2.1(heat from surrounding) = 14.2 (heat from hetaer)
is tht easier...
ah ha now i get it Thanks dude
so its 14.2 g after all :D
n no IGSTUDENT im not pursuing a job in the physics field im planning fer medical inshAllah :) n i jus wanna ace it so i can get an admission in a good university :) n the way i looked up fer the requirements, 7 A* fer university of birmingham really made me think seriously over the whole " enjoy life n study up along side it " issue
Post by: SGVaibhav on June 03, 2009, 10:54:12 am
quesiton (1)(c) is hard
the answer is 24 to 28 m
how do u get that?
Post by: Shogun on June 03, 2009, 10:56:29 am
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: Ibiza279 on June 03, 2009, 11:01:00 am
solve this hard questoin
quesiton (1)(c) is hard
the answer is 24 to 28 m
how do u get that?
answer is 1/2 X 12 X 5 = 30 m
but as the graph is abit curved so just take out 2-4 units, any of the whole numbers u like frm that range, frm the answer
thats what our teacher taught us n so u get the answer as 28
i hope that helps
Post by: Ibiza279 on June 03, 2009, 11:01:59 am
lol u got it now. 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)
well got it now Thanks shogun that really helped :)
Post by: astarmathsandchemistry on June 03, 2009, 11:03:12 am
THE FOUR EQUATIONS OF MOTION CAN ONLY ONLY ONLY BE USED WHEN ACCELERATION IS CONSTANT
thanks
Post by: Shogun on June 03, 2009, 11:04:36 am
solve this hard questoin
quesiton (1)(c) is hard
the answer is 24 to 28 m
how do u get that?
yup what ibiz said, or u can make a trapezium and traiangle, find thier areas and add them up..
Post by: Priceless on June 03, 2009, 11:06:26 am
+rep 2 u.....n gud luck 4 ur xam...lol...im not sure if u need it but still all da best! :D ;)
Post by: Ghost Of Highbury on June 03, 2009, 11:07:56 am
u have to draw a tangent to the point (where the dent lies)
this way u get the point on the x-axis near 24
24-20 = 4 --> 4/2 = 2
2*12 = 24m!
hope this helped
Post by: IGCSE hater! on June 03, 2009, 11:08:30 am
Post by: Shogun on June 03, 2009, 11:10:08 am
THNKU SHOGUN SOOOO MUCH....rely solved a big doubt...i du get it nw....phy xam ll b no sweat 4 u cuz da way u read ques......wow. ;)
+rep 2 u.....n gud luck 4 ur xam...lol...im not sure if u need it but still all da best! :D ;)
lol, i do still needd it, cuz when i get tennessed i loose my abbility to read questions as prperly as i do at home...
nywaz Thanks and good luck to u too.. hope the exam would be no sweat to u too inshallah
Post by: Ibiza279 on June 03, 2009, 11:10:19 am
Post by: Ghost Of Highbury on June 03, 2009, 11:11:13 am
okk..i have attached it...1c...
u have to draw a tangent to the point (where the dent lies)
this way u get the point on the x-axis near 24
24-20 = 4 --> 4/2 = 2
2*12 = 24m!
hope this helped
if u see carefully...the curve touches the x-axis at 25..
but u dont have to take the curve...its the tangent to the curve
therefore the answer lies between 24<= ans <= 28
Post by: Ghost Of Highbury on June 03, 2009, 11:12:13 am
uh wat r the four equations of motion again :D
s= ut + 0.5a(t^2)
s = (u+v)/2
v = u + at
v^2 = u^2 + 2as
:)
Post by: Ghost Of Highbury on June 03, 2009, 11:14:10 am
alright let see hopw can i expalin
16.3 (heat from heater +heat from surrounding) - 2.1(heat from surrounding) = 14.2 (heat from hetaer)
is tht easier...
wow!...great explanation shogun
tks a lot
u will surely do well in ur physics
best of luck
+rep
Post by: Shogun on June 03, 2009, 11:15:20 am
alright let see hopw can i expalin
16.3 (heat from heater +heat from surrounding) - 2.1(heat from surrounding) = 14.2 (heat from hetaer)
is tht easier...
wow!...great explanation shogun
tks a lot
u will surely do well in ur physics
best of luck
+rep
lol Thanks, u 2 ;D :D
Post by: Ibiza279 on June 03, 2009, 11:15:32 am
Post by: Shogun on June 03, 2009, 11:16:18 am
Post by: idol2009 on June 03, 2009, 11:17:57 am
Post by: Ghost Of Highbury on June 03, 2009, 11:18:14 am
wow Thanks dude ill make a note of it :)
if that was for me
welcome
:D
Post by: Ibiza279 on June 03, 2009, 11:18:40 am
alright g2g, got to go 2 school to pick up my small bro, then gonna do past papers
all the best fer the exam dude inshAllah its gona go well fer all of us mainly cause of u
well tk dude bubbye
Post by: Ibiza279 on June 03, 2009, 11:19:19 am
wow Thanks dude ill make a note of it :)
if that was for me
welcome
:D
lol it is ;D
Post by: Kim on June 03, 2009, 11:20:03 am
Post by: Ibiza279 on June 03, 2009, 11:23:56 am
hey cud sum one explain how to calculate the voltage using a CRO? ???
u need to knw the value of voltage per square in the CRO when u knw that note down how many squares the crest of the wave goes to n then multiply it with the voltage per square n that gives u the total voltage
Post by: 247sports on June 03, 2009, 11:32:38 am
2c)
8c)
and in may june 2007
2a) and 9a)
and i need explanation i hav the markin scheme but i need to understnad it
thnk u ;)
Post by: ZeroZero82 on June 03, 2009, 11:33:47 am
Post by: Ibiza279 on June 03, 2009, 11:41:03 am
I hav some quests in ppr may june 2002
2c)
8c)
and in may june 2007
2a) and 9a)
and i need explanation i hav the markin scheme but i need to understnad it
thnk u ;)
2c: the change in speed is 9.5 m/s cause frm 9.5,when the ball touches the grnd it comes to 0 so its 9.5 i hope thats what the mark scheme says
8c: the function of a diode is that its a rectified, it changes frm A.C to D.C so as the A.C current flows in forward bias of the diode, the diode allows the flow but when A.C flows in the opposite direction, the diode doesn't allow that so A.C changes to D.C
n for 2007 i don't hav the paper so if u give me the question, ill clear it
all the best
Post by: SGVaibhav on June 03, 2009, 11:50:01 am
uh wat r the four equations of motion again :D
s= ut + 0.5a(t^2)
s = (u+v)/2
v = u + at
v^2 = u^2 + 2as
:)
i found fifth equation of motion
i dont think its there in portion, but i found 5th one
its rocks.
Post by: SGVaibhav on June 03, 2009, 11:50:17 am
okk..i have attached it...1c...
u have to draw a tangent to the point (where the dent lies)
this way u get the point on the x-axis near 24
24-20 = 4 --> 4/2 = 2
2*12 = 24m!
hope this helped
it helped
thanks
Post by: Kim on June 03, 2009, 11:50:31 am
kk thanks ;Dhey cud sum one explain how to calculate the voltage using a CRO? ???
u need to knw the value of voltage per square in the CRO when u knw that note down how many squares the crest of the wave goes to n then multiply it with the voltage per square n that gives u the total voltage
Post by: Ghost Of Highbury on June 03, 2009, 11:50:56 am
okk..i have attached it...1c...
u have to draw a tangent to the point (where the dent lies)
this way u get the point on the x-axis near 24
24-20 = 4 --> 4/2 = 2
2*12 = 24m!
hope this helped
it helped
thanks
welcome.
Post by: Ibiza279 on June 03, 2009, 11:53:27 am
Nov. 2005 11)a) How do we draw the diagram!? :-\ explain.
this is the answer to Q11 A
Post by: Ibiza279 on June 03, 2009, 11:54:35 am
kk thanks ;Dhey cud sum one explain how to calculate the voltage using a CRO? ???
u need to knw the value of voltage per square in the CRO when u knw that note down how many squares the crest of the wave goes to n then multiply it with the voltage per square n that gives u the total voltage
ur welcome :)
Post by: Aodian on June 03, 2009, 11:54:57 am
only thing is that.. I've never really used the equations of motions in any paper.. so.. should i still bother? because i dont know where exactly to use the equations though I know what they're for
Post by: 12345abc on June 03, 2009, 11:56:44 am
Post by: ZeroZero82 on June 03, 2009, 11:57:32 am
Nov. 2005 11)a) How do we draw the diagram!? :-\ explain.
this is the answer to Q11 A
Thanks. Really helped :D
Post by: simply.me on June 03, 2009, 11:58:33 am
Post by: Ghost Of Highbury on June 03, 2009, 11:58:43 am
By the way the equations of motion.. i always have problems remembering them.. cudnt be bothered to make a mnemonic to try understand them..i remember it this way
only thing is that.. I've never really used the equations of motions in any paper.. so.. should i still bother? because i dont know where exactly to use the equations though I know what they're for
newton had 3 sons..satu, vatu and vasu (indian names)
satu => s= ut + 0.5at^2 (s,u,t,a = satu)
vatu => v=u +at (v, u, a, t =vatu)
vasu => v^2 = u^2 + 2as (v, u, a, =vasu)
i know its funny..
but good to remember the formulaes
hope it helped :)
Post by: Ibiza279 on June 03, 2009, 11:59:53 am
By the way the equations of motion.. i always have problems remembering them.. cudnt be bothered to make a mnemonic to try understand them..
only thing is that.. I've never really used the equations of motions in any paper.. so.. should i still bother? because i dont know where exactly to use the equations though I know what they're for
well they r important really really important u knwing them might aswell save u some marks in the exam, not knwing them is a bad gamble so jus remember um tk
n ill get on to the radiation part after 5 mins :)
Post by: Ghost Of Highbury on June 03, 2009, 12:00:39 pm
uh wat r the four equations of motion again :D
s= ut + 0.5a(t^2)
s = (u+v)/2
v = u + at
v^2 = u^2 + 2as
:)
i found fifth equation of motion
i dont think its there in portion, but i found 5th one
its rocks.
wat is it ...??
is it v=d/t??
Post by: Ibiza279 on June 03, 2009, 12:03:15 pm
Nov. 2005 11)a) How do we draw the diagram!? :-\ explain.
this is the answer to Q11 A
Thanks. Really helped :D
ur welcome :)
Post by: Aodian on June 03, 2009, 12:05:57 pm
Post by: 247sports on June 03, 2009, 12:06:12 pm
Thanks but sry to burst ur bubble but the answer in the markin scheme is 1.5 n 17.5 m/s :-\I hav some quests in ppr may june 2002
2c)
8c)
and in may june 2007
2a) and 9a)
and i need explanation i hav the markin scheme but i need to understnad it
thnk u ;)
2c: the change in speed is 9.5 m/s cause frm 9.5,when the ball touches the grnd it comes to 0 so its 9.5 i hope thats what the mark scheme says
8c: the function of a diode is that its a rectified, it changes frm A.C to D.C so as the A.C current flows in forward bias of the diode, the diode allows the flow but when A.C flows in the opposite direction, the diode doesn't allow that so A.C changes to D.C
n for 2007 i don't hav the paper so if u give me the question, ill clear it
all the best
n sry i neede to ask 9c) not 8c)
n neva mind for 2007 they r all daigrams
Thanks alot aneways :)
Post by: astarmathsandphysics on June 03, 2009, 12:06:25 pm
I NEED HELP IN M/J 2008 Q.10)a,b,&c please ..
which paper?
Post by: unknown on June 03, 2009, 12:09:09 pm
jun 2005 11q diagram help
n jun 2007 q 6bi) q 10b) n 11b)
n ya nov 2007 10b
thx in advance........
Post by: Kim on June 03, 2009, 12:13:00 pm
I m sure he meant physics paper 3I NEED HELP IN M/J 2008 Q.10)a,b,&c please ..
which paper?
Post by: astarmathsandphysics on June 03, 2009, 12:13:07 pm
Post by: 247sports on June 03, 2009, 12:14:01 pm
can any1 plz explain deflection of radiations in magnetic fields??? and any easy way to remember themsee usually they need u to answer whether it deflectin into or out of teh page
so for alpha its ALWAYS out of THE PAGE wherreas beta is always into THE PAGE
PLZZ CORRECT ME IF I AM WRONG
n always mwntion the wrd curvd if the radiation is in bettween a magnetic field
hope this helps
gud luck
Post by: Ghost Of Highbury on June 03, 2009, 12:15:20 pm
but which paper? Post the paper number toopaper 3
Post by: theigstudent on June 03, 2009, 12:16:24 pm
Post by: theigstudent on June 03, 2009, 12:18:17 pm
june03 paper no3___________Q3a and @11 a and b
Post by: ny on June 03, 2009, 12:19:40 pm
thanks.
Post by: 247sports on June 03, 2009, 12:20:30 pm
alpha in
n beta out
got it ;)
Post by: ~Mimi~ on June 03, 2009, 12:20:58 pm
Post by: theigstudent on June 03, 2009, 12:22:45 pm
aaa thnk u IGBOY
alpha in
n beta out
got it ;)
again a correction i m theigstudent ;)
Post by: Q80BOY on June 03, 2009, 12:24:40 pm
ans. for unknown, hope this helps :)
Post by: astarmathsandphysics on June 03, 2009, 12:25:33 pm
plzzzzz astar....i m gone............help urgent or else i wil fail.............
jun 2005 11q diagram help
n jun 2007 q 6bi) q 10b) n 11b)
n ya nov 2007 10b
thx in advance........
draw a commutator connected to a battery
6bi)90 degrees
2007 jun 10b) move the resistor so both resistora sre in series with the thermistor
nov 2007 10b Connect the not to the thermometer and this out put and the humdity sensor output to the and gate. Commect the and gate to the alarm
Post by: Kim on June 03, 2009, 12:26:20 pm
but which paper? Post the paper number tooits already said in the question if u r askin for the variant then i dunno
Post by: Ghost Of Highbury on June 03, 2009, 12:27:47 pm
could some 1 help me withi cud figure out how to draw the scale drawing
june03 paper no3___________Q3a and @11 a and b
but how do u find the weight of the box
????
Post by: X Abdulrahman X on June 03, 2009, 12:27:59 pm
May/June 2003
ans. for unknown, hope this helps :)
haha, results wont be accurate, no one will stop the watch !
u need to do it again, this time dont point at the guy with the watch ;)
Post by: ~Mimi~ on June 03, 2009, 12:29:24 pm
Post by: asus on June 03, 2009, 12:29:37 pm
Post by: theigstudent on June 03, 2009, 12:30:09 pm
could some 1 help me withi cud figure out how to draw the scale drawing
june03 paper no3___________Q3a and @11 a and b
but how do u find the weight of the box
????
sorrrie no idea
Post by: Kim on June 03, 2009, 12:30:45 pm
could anyone tell me some uses of alpha.beta and gamma rays?i dunno them seperately but here are sum uses for radiations
thanks.
smoke detectors
thickness gauge
checking leakage in pipes
carbon dating
treatment of cancer
detecting faulty welds
Post by: simply.me on June 03, 2009, 12:32:28 pm
I NEED HELP IN M/J 2008 Q.10)a,b,&c please ..
can any1 answer me please !!??
Post by: astarmathsandphysics on June 03, 2009, 12:34:02 pm
could some 1 help me with
june03 paper no3___________Q3a and @11 a and b
use a scale 100N=1cm. draw a line 12.2cm starting at the left hand pin on the bar parallel to the 1220N force, and a line 9.5 cm staring at the right hand pin parallel to th 950N force. Where these to lines meet draw a diangonal to the opposite corner of the paralllelogram. Timnes this length by 100 to get the force in N.
11a)Use aluminium or lead sheets between the source and a detector. Nothing is detected therefore an alpha emittor
b)Use the left hand rule. Deflected into paper
Post by: Ibiza279 on June 03, 2009, 12:35:08 pm
Thanks but sry to burst ur bubble but the answer in the markin scheme is 1.5 n 17.5 m/s :-\I hav some quests in ppr may june 2002
2c)
8c)
and in may june 2007
2a) and 9a)
and i need explanation i hav the markin scheme but i need to understnad it
thnk u ;)
2c: the change in speed is 9.5 m/s cause frm 9.5,when the ball touches the grnd it comes to 0 so its 9.5 i hope thats what the mark scheme says
8c: the function of a diode is that its a rectified, it changes frm A.C to D.C so as the A.C current flows in forward bias of the diode, the diode allows the flow but when A.C flows in the opposite direction, the diode doesn't allow that so A.C changes to D.C
n for 2007 i don't hav the paper so if u give me the question, ill clear it
all the best
n sry i neede to ask 9c) not 8c)
n neva mind for 2007 they r all daigrams
Thanks alot aneways :)
lol sorry fer the incorrect answers well then the other alternative is first one is 9.5 - 8 and the second one is 9.5 + 8 :D
well it does make sense change in speed at that point is 1.5 n change in velocity is 17.5 sorry fer the wrong answer :)
Post by: Ibiza279 on June 03, 2009, 12:36:22 pm
Post by: Ghost Of Highbury on June 03, 2009, 12:36:59 pm
could some 1 help me withQ3a answer
june03 paper no3___________Q3a and @11 a and b
no idea of Q10
find it attached
Post by: sweetie on June 03, 2009, 12:40:21 pm
in 1 variant paper oct 08, i couldnt do q2.d
plzzzzzzzz give me da solution
xam is morrow
Post by: theigstudent on June 03, 2009, 12:41:09 pm
could some 1 help me with
june03 paper no3___________Q3a and @11 a and b
use a scale 100N=1cm. draw a line 12.2cm starting at the left hand pin on the bar parallel to the 1220N force, and a line 9.5 cm staring at the right hand pin parallel to th 950N force. Where these to lines meet draw a diangonal to the opposite corner of the paralllelogram. Timnes this length by 100 to get the force in N.
11a)Use aluminium or lead sheets between the source and a detector. Nothing is detected therefore an alpha emittor
b)Use the left hand rule. Deflected into paper
i didnt get the drawing part could some 1 attach the drawing
Thanks in advance
n Thanks a lot astar
Post by: astarmathsandphysics on June 03, 2009, 12:41:47 pm
nor gaTE EXPLAINED http://en.wikipedia.org/wiki/NOR_gateI NEED HELP IN M/J 2008 Q.10)a,b,&c please ..
can any1 answer me please !!??
ci)BOTH NEED TO BE OFF. tHE HEATER IS ON BECAUSE THE TMP IS LOW SO the out put is high
cii))off off
Post by: Ghost Of Highbury on June 03, 2009, 12:42:27 pm
@ theigstudentcould some 1 help me withQ3a answer
june03 paper no3___________Q3a and @11 a and b
no idea of Q10
find it attached
i have attached the drawing
Post by: theigstudent on June 03, 2009, 12:44:07 pm
could u help me with the page no on which the attachment is@ theigstudentcould some 1 help me withQ3a answer
june03 paper no3___________Q3a and @11 a and b
no idea of Q10
find it attached
i have attached the drawing
Thanks
Post by: astarmathsandphysics on June 03, 2009, 12:45:07 pm
emergency case! plz help
in 1 variant paper oct 08, i couldnt do q2.d
plzzzzzzzz give me da solution
xam is morrow
what ever 2 masses you choose The reaction will be 9.81(m1+m2)
Post by: astarmathsandphysics on June 03, 2009, 12:47:06 pm
attachment is here
Post by: sweetie on June 03, 2009, 12:47:20 pm
and wats ur answer??
Post by: AN10 on June 03, 2009, 12:48:02 pm
Post by: Kim on June 03, 2009, 12:48:51 pm
Post by: astarmathsandphysics on June 03, 2009, 12:49:30 pm
were did u get .81 from???????
should have been 9.81 I corrected it
Post by: theigstudent on June 03, 2009, 12:50:33 pm
sorrie i didnt see it
Thanks a lot
Post by: unknown on June 03, 2009, 12:51:59 pm
wht is happening is tht d ans or nop plzzzzzzz dnt confuse me.....i m already so confusedMay/June 2003
ans. for unknown, hope this helps :)
haha, results wont be accurate, no one will stop the watch !
u need to do it again, this time dont point at the guy with the watch ;)
Post by: astarmathsandphysics on June 03, 2009, 12:52:06 pm
guyz im confused :-\.... when a ques asks u abt da maximum potential difference measured of a wave shown on CRO, is it da amplitude of a wave or da difference of the max n min voltage value??
It is the amplitude of the wave form. The CRO have a scale -volts per div- so you must change your reading to volts
Post by: simply.me on June 03, 2009, 12:52:25 pm
nor gaTE EXPLAINED http://en.wikipedia.org/wiki/NOR_gateI NEED HELP IN M/J 2008 Q.10)a,b,&c please ..
can any1 answer me please !!??
ci)BOTH NEED TO BE OFF. tHE HEATER IS ON BECAUSE THE TMP IS LOW SO the out put is high
cii))off off
thhhxxxx alot for ur help
Post by: Ghost Of Highbury on June 03, 2009, 12:52:36 pm
oh ya Thankswelcome :D
sorrie i didnt see it
Thanks a lot
Post by: simply.me on June 03, 2009, 12:53:31 pm
Post by: astarmathsandphysics on June 03, 2009, 12:53:52 pm
wht is happening is tht d ans or nop plzzzzzzz dnt confuse me.....i m already so confusedMay/June 2003
ans. for unknown, hope this helps :)
haha, results wont be accurate, no one will stop the watch !
u need to do it again, this time dont point at the guy with the watch ;)
https://studentforums.biz/index.php/topic,1798.420.html
your answer is at top of this page
Post by: astarmathsandphysics on June 03, 2009, 12:57:29 pm
m/j 2007 q 1b a .. can any one shows me the working done ?
the car will leave the track on a tangent.
ii)the centrifugal force is greater than the maximum possible friction force
Post by: Ghost Of Highbury on June 03, 2009, 01:00:42 pm
i think it is centripetal force which is greater than the frictional force???m/j 2007 q 1b a .. can any one shows me the working done ?
the car will leave the track on a tangent.
ii)the centrifugal force is greater than the maximum possible friction force
Post by: unknown on June 03, 2009, 01:04:39 pm
sir i m asking fr jun 2003 7c(diagram) i understood rest of d ans bt i stil didnt understand tht jun 07 10b i mean can u explain me completely wht exactly 2 rite n ya some notes on potential dividerwht is happening is tht d ans or nop plzzzzzzz dnt confuse me.....i m already so confusedMay/June 2003
ans. for unknown, hope this helps :)
haha, results wont be accurate, no one will stop the watch !
u need to do it again, this time dont point at the guy with the watch ;)
https://studentforums.biz/index.php/topic,1798.420.html
your answer is at top of this page
Post by: simply.me on June 03, 2009, 01:06:18 pm
m/j 2007 q 1b a .. can any one shows me the working done ?
the car will leave the track on a tangent.
ii)the centrifugal force is greater than the maximum possible friction force
thxxx agaain m8
Post by: Q80BOY on June 03, 2009, 01:10:28 pm
May/June 2003
ans. for unknown, hope this helps :)
haha, results wont be accurate, no one will stop the watch !
u need to do it again, this time dont point at the guy with the watch ;)
?? i dont understand ???
the man will stop the watch !! why is it inaccuarte ?? :-\
Post by: asus on June 03, 2009, 01:10:44 pm
so sad.. :'(
nway, good luck u guys..
bye
Post by: astarmathsandphysics on June 03, 2009, 01:13:04 pm
Post by: nid404 on June 03, 2009, 01:13:32 pm
i think it is centripetal force which is greater than the frictional force???m/j 2007 q 1b a .. can any one shows me the working done ?
the car will leave the track on a tangent.
ii)the centrifugal force is greater than the maximum possible friction force
i thought so
Post by: sweetie on June 03, 2009, 01:14:00 pm
Post by: nid404 on June 03, 2009, 01:15:20 pm
i still dunno were did 9.81 cum from???
for w8???
Post by: Ghost Of Highbury on June 03, 2009, 01:15:37 pm
no one here wants to help me..hey asus
so sad.. :'(
nway, good luck u guys..
bye
were u talking abt the graph question
i have attached it
i think its correct
maybe astar and nid can check it
Post by: astarmathsandphysics on June 03, 2009, 01:16:04 pm
Post by: asus on June 03, 2009, 01:16:34 pm
could anybody draw the graph for paper 3 nov02 question 1 a)..please..
here is the quest astar..
so lucky when someone is willing to help..
:)
Post by: Ghost Of Highbury on June 03, 2009, 01:17:22 pm
i have attached the answer
plz scroll up
astar and nid can chk it
:D
Post by: astarmathsandphysics on June 03, 2009, 01:17:28 pm
no one here wants to help me..hey asus
so sad.. :'(
nway, good luck u guys..
bye
were u talking abt the graph question
i have attached it
i think its correct
maybe astar and nid can check it
yes I agree
Post by: Kim on June 03, 2009, 01:17:52 pm
Post by: asus on June 03, 2009, 01:18:20 pm
no one here wants to help me..hey asus
so sad.. :'(
nway, good luck u guys..
bye
were u talking abt the graph question
i have attached it
i think its correct
maybe astar and nid can check it
yeay...!
same as mine...
MEGA thank u to u!
Post by: unknown on June 03, 2009, 01:18:30 pm
hello wil he stop or noMay/June 2003
ans. for unknown, hope this helps :)
haha, results wont be accurate, no one will stop the watch !
u need to do it again, this time dont point at the guy with the watch ;)
?? i dont understand ???
the man will stop the watch !! why is it inaccuarte ?? :-\
u plz tel me
i m gng crazy
n d diagram is correct or nop plzz ans
Post by: X Abdulrahman X on June 03, 2009, 01:19:06 pm
May/June 2003
ans. for unknown, hope this helps :)
haha, results wont be accurate, no one will stop the watch !
u need to do it again, this time dont point at the guy with the watch ;)
?? i dont understand ???
the man will stop the watch !! why is it inaccuarte ?? :-\
cuz u shot him silly, i was joking ! :P
Post by: Ghost Of Highbury on June 03, 2009, 01:19:46 pm
no one here wants to help me..hey asus
so sad.. :'(
nway, good luck u guys..
bye
were u talking abt the graph question
i have attached it
i think its correct
maybe astar and nid can check it
yes I agree
tks astar
i had a doubt in that
why i am getting -rep
hell!!
Post by: astarmathsandphysics on June 03, 2009, 01:20:34 pm
hello wil he stop or noMay/June 2003
ans. for unknown, hope this helps :)
haha, results wont be accurate, no one will stop the watch !
u need to do it again, this time dont point at the guy with the watch ;)
?? i dont understand ???
the man will stop the watch !! why is it inaccuarte ?? :-\
u plz tel me
i m gng crazy
n d diagram is correct or nop plzz ans
It is not exactly correct. The diagonal should be vertical
Post by: nid404 on June 03, 2009, 01:20:38 pm
Post by: asus on June 03, 2009, 01:21:00 pm
no one here wants to help me..hey asus
so sad.. :'(
nway, good luck u guys..
bye
were u talking abt the graph question
i have attached it
i think its correct
maybe astar and nid can check it
yes I agree
tks astar
i had a doubt in that
why i am getting -rep
hell!!
i gave +rep..
;D
Post by: Ghost Of Highbury on June 03, 2009, 01:21:32 pm
+rep nid
for the phy question i asked u previously
Post by: Q80BOY on June 03, 2009, 01:22:19 pm
hello wil he stop or noMay/June 2003
ans. for unknown, hope this helps :)
haha, results wont be accurate, no one will stop the watch !
u need to do it again, this time dont point at the guy with the watch ;)
?? i dont understand ???
the man will stop the watch !! why is it inaccuarte ?? :-\
u plz tel me
i m gng crazy
n d diagram is correct or nop plzz ans
It is not exactly correct. The diagonal should be vertical
so the measuring tape should be vertical ??
why?
Post by: nid404 on June 03, 2009, 01:22:52 pm
hello wil he stop or noMay/June 2003
ans. for unknown, hope this helps :)
haha, results wont be accurate, no one will stop the watch !
u need to do it again, this time dont point at the guy with the watch ;)
?? i dont understand ???
the man will stop the watch !! why is it inaccuarte ?? :-\
u plz tel me
i m gng crazy
n d diagram is correct or nop plzz ans
It is not exactly correct. The diagonal should be vertical
does that really matter astar. the diagonal is not straight cus he's drawn the lines in that way....i guess :-\
correct me if im wrong
Post by: unknown on June 03, 2009, 01:37:00 pm
so somonne plz rel me d rite diagram or else i wil go madhello wil he stop or noMay/June 2003
ans. for unknown, hope this helps :)
haha, results wont be accurate, no one will stop the watch !
u need to do it again, this time dont point at the guy with the watch ;)
?? i dont understand ???
the man will stop the watch !! why is it inaccuarte ?? :-\
u plz tel me
i m gng crazy
n d diagram is correct or nop plzz ans
It is not exactly correct. The diagonal should be vertical
does that really matter astar. the diagonal is not straight cus he's drawn the lines in that way....i guess :-\
correct me if im wrong
n ya wht is this potential divider stuff help me.......
Post by: Ghost Of Highbury on June 03, 2009, 01:41:38 pm
astar plzz do something
Post by: Ghost Of Highbury on June 03, 2009, 01:43:14 pm
????
Post by: astarmathsandphysics on June 03, 2009, 01:49:58 pm
Post by: Hope on June 03, 2009, 02:45:24 pm
The question makes it seem like 2.1 g of ice melted..
Also, qn 6b), they've inverted the equation to find the refractive index.. the 30 degrees angle is like the incident angle, however they've assumed it's the refractive angle. I'm not sure why, but is it because, if the angle we're trying to calculate, were to emerge into the glass, that's the angle it would form?
Help please :(
Post by: astarmathsandphysics on June 03, 2009, 02:50:21 pm
Post by: Hope on June 03, 2009, 03:18:56 pm
Post by: Ghost Of Highbury on June 03, 2009, 03:20:41 pm
Hey..may anyone please clarify why in November 2008 Qn c), the value of the ice melted is = 14.2??
The question makes it seem like 2.1 g of ice melted..
Also, qn 6b), they've inverted the equation to find the refractive index.. the 30 degrees angle is like the incident angle, however they've assumed it's the refractive angle. I'm not sure why, but is it because, if the angle we're trying to calculate, were to emerge into the glass, that's the angle it would form?
Help please :(
u do it like this
n = sin i / sin r
1.49 = sin 30 / sin r
sin r = sin 30/ 1.49
sin r = 0.3355
r = sin(-1) 0.3355
r = 19.6 degree
i think the markscheme is wrong
they have applied the incorrect formula
it is n = sin i / sin r
but they have used n = sin r / sin i
------------------------------------
for nov 08 Q c.>(the ice one)
shogun has explained it clearly
here https://studentforums.biz/index.php/topic,1798.360.html
Post by: Ghost Of Highbury on June 03, 2009, 03:22:40 pm
shogun explained it really well
Post by: nid404 on June 03, 2009, 03:28:35 pm
Post by: Ghost Of Highbury on June 03, 2009, 03:29:46 pm
nid
i too was wondering abt that
pretty funny
lol..
hey nid ... chk out the question i have just answered... is it correct??
i think the markschemes wrong
nov 08 paper 3 1st variant Q 6.)b.)
Post by: sweetie on June 03, 2009, 03:31:05 pm
9.81 is the accleration due to gravity I useed weight=9.81*mass
ok now i got it
thanx 4 da help
gud luk
Post by: Hope on June 03, 2009, 03:31:41 pm
And wonderful explanation Shogun, thank you :)
Post by: goin4dakill on June 03, 2009, 03:32:01 pm
Hey..may anyone please clarify why in November 2008 Qn c), the value of the ice melted is = 14.2??
The question makes it seem like 2.1 g of ice melted..
Also, qn 6b), they've inverted the equation to find the refractive index.. the 30 degrees angle is like the incident angle, however they've assumed it's the refractive angle. I'm not sure why, but is it because, if the angle we're trying to calculate, were to emerge into the glass, that's the angle it would form?
Help please :(
Hey, so i see someone answered ur second question but for the first one..I got a little mixed up with that as well.
What they are asking is for the amount of water that was melted.. AND that is in the beaker. So therefore u gotta do..18.4- 2.1, which then equals 14.2.
I dont know if that was understandable, i mean im remembering the question of the top of my head.
By the way, was it me, or was the paper a little hard. What do u think Hope??? Noone will answer this question -.-
AND ALSO I THINK THE MARK SCHEME WAS WRONG!!!!!! I thought that too, because for sure it is Sini/sinr
Post by: Eamyzz on June 03, 2009, 03:32:23 pm
Post by: Ghost Of Highbury on June 03, 2009, 03:32:34 pm
thank you so much Adi, for directing me to that! :Dwelcome :)
And wonderful explanation Shogun, thank you :)
Post by: Hope on June 03, 2009, 03:35:14 pm
Post by: Eamyzz on June 03, 2009, 03:36:56 pm
Post by: nid404 on June 03, 2009, 03:37:27 pm
no ideasorry boss marksheme is right.
nid
i too was wondering abt that
pretty funny
lol..
hey nid ... chk out the question i have just answered... is it correct??
i think the markschemes wrong
nov 08 paper 3 1st variant Q 6.)b.)
in this case 30ois the angle of refraction.....refractive index of glass is 1.49 i can't explain it but im sure ur smart enough to understand
it's still sini/sinr......just imagine the ray entering from the other side of the block
Post by: Ghost Of Highbury on June 03, 2009, 03:40:40 pm
no ideasorry boss marksheme is right.
nid
i too was wondering abt that
pretty funny
lol..
hey nid ... chk out the question i have just answered... is it correct??
i think the markschemes wrong
nov 08 paper 3 1st variant Q 6.)b.)
in this case 30ois the angle of refraction.....refractive index of glass is 1.49 i can't explain it but im sure ur smart enough to understand
okay..
tks nid..
but they are aksing to find the angle of refraction using the angle of refraction
but y in the markscheme they write that n = sin r / sin i??
strange!!
Post by: sweetie on June 03, 2009, 03:44:33 pm
in 06 oct q8.a were is switch suppose 2 b?????????
Post by: nid404 on June 03, 2009, 03:46:41 pm
like speed of light in air=3x108 and in glass=2x108
refractive index of glass=3x108/2x108
but for light coming out it's 2x108/3x108
i hope u get it...i s at explaining this physics
Post by: Eamyzz on June 03, 2009, 03:48:11 pm
1 mor que
in 06 oct q8.a were is switch suppose 2 b?????????
on the right or the left line after lamp X and before lamp Y
dd u gt it ? :)
i will try 2 upload it if possible :)
Post by: Ghost Of Highbury on June 03, 2009, 03:50:44 pm
tks yaar
@notty me
find the answer attached
(nid404 plz chk it)
tks
Post by: astarmathsandchemistry on June 03, 2009, 03:51:11 pm
Its 5:38 PM here in ksa, and i studied the notes carefully revised the last 5years of papers, and this always happen to me I JUST DONT KNOW WHATS LEFT TO DO!! :SS
I usually start predicting questions, but i cant do that for physics can i??
please advise me on what to do thanks
Post by: nid404 on June 03, 2009, 03:52:16 pm
@reko CHILLAX
Post by: X Abdulrahman X on June 03, 2009, 03:53:22 pm
Guys what should i be doing right now??
Its 5:38 PM here in ksa, and i studied the notes carefully revised the last 5years of papers, and this always happen to me I JUST DONT KNOW WHATS LEFT TO DO!! :SS
I usually start predicting questions, but i cant do that for physics can i??
please advise me on what to do thanks
take a rest, then do 2003 physics paper, since many questions from chem were from 2003 i think, then just re read some stuff and try to study and remember the equations needed very well :)
Post by: Ghost Of Highbury on June 03, 2009, 03:54:24 pm
don't worry so much
be sure that u have studied well!
u'll do great in ur exam
good luck :)
Post by: astarmathsandchemistry on June 03, 2009, 03:57:39 pm
yup right adihehehehe OK I WILL TRY :P BUT I AM SOO SCARED :(
@reko CHILLAX
THanks guys for the motivation :)
i hope i do ADi , thanks man good luck to alll :D
Post by: Eamyzz on June 03, 2009, 04:01:01 pm
yup right adihehehehe OK I WILL TRY :P BUT I AM SOO SCARED :(
@reko CHILLAX
THanks guys for the motivation :)
i hope i do ADi , thanks man good luck to alll :D
come on realax it will b easy insha'alah u dd ur best 5alas ;D
Post by: Shogun on June 03, 2009, 04:02:59 pm
Post by: astarmathsandchemistry on June 03, 2009, 04:03:28 pm
ok fine :)yup right adihehehehe OK I WILL TRY :P BUT I AM SOO SCARED :(
@reko CHILLAX
THanks guys for the motivation :)
i hope i do ADi , thanks man good luck to alll :D
come on realax it will b easy insha'alah u dd ur best 5alas ;D
i hope so all yesma3 mennek, yeah i studied really good :)
can u pls pm me ur email
Post by: astarmathsandchemistry on June 03, 2009, 04:04:10 pm
yeah 3ad, even i feel tht i finished, but something tells me i have to stress more in radioavtivity....yah walla
ana 5ayef men el radioactivity qstns :S
Post by: sweetie on June 03, 2009, 04:04:40 pm
ohhh...got it got itbut they want a switch dat turns off lamp Y and Z ???
tks yaar
@notty me
find the answer attached
(nid404 plz chk it)
tks
Post by: Shogun on June 03, 2009, 04:05:18 pm
Post by: astarmathsandchemistry on June 03, 2009, 04:06:11 pm
lol me 2 and ofcorse some of tht velocity stuff and heat....lol tht sucksloool, i am also scared of......mm.....EVERYTHING!!! HAHAHA :P
Post by: X Abdulrahman X on June 03, 2009, 04:07:12 pm
Post by: astarmathsandchemistry on June 03, 2009, 04:08:00 pm
PLEASE?? thanks!!
Post by: astarmathsandchemistry on June 03, 2009, 04:10:09 pm
the only question im worried about is anything related to specific heat capacity, because for some reason i cant remember the equaions :-\yeah man i am wid u on this one, the specific latent heat and the Latent of heat of vaporisation and fusion loool kinda confusing, but just repeat them many times to urself and you'll be ok!! and u can like write them and keep it ur pocket so that everytime u just take it out and have alook on it that may sound stupid but it really helps try it lol!! :P
Post by: Eamyzz on June 03, 2009, 04:10:51 pm
eg. speed
vectors has both magnitude AND direction
eg. velocity
hope its clear
Post by: Guthixol on June 03, 2009, 04:12:00 pm
paper 3 oct/nov 2008 q (2) all please and :D thank you
Post by: astarmathsandchemistry on June 03, 2009, 04:13:37 pm
lsn scalars is only magnitude with NO directionnooooooo hahaha thats so simple come on
eg. speed
vectors has both magnitude AND direction
eg. velocity
hope its clear
I meant drawing the vectors with the angles and the scales u know that?
and the parrellogram thingy :s
Post by: Ghost Of Highbury on June 03, 2009, 04:13:57 pm
it does close it...ohhh...got it got itbut they want a switch dat turns off lamp Y and Z ???
tks yaar
@notty me
find the answer attached
(nid404 plz chk it)
tks
X will not work
only Y and Z
Post by: Dramien on June 03, 2009, 04:16:55 pm
Post by: Ghost Of Highbury on June 03, 2009, 04:19:47 pm
may someone answer this question
paper 3 oct/nov 2008 q (2) all please and :D thank you
heres how u do it
a) find it attached
b) if the masses are in equilibrium and there is no net moment, the disc will not move toward any side
c) (200/100)N * 4m = 8Nm
(100/100)N * 8m = 8Nm
moment due to first mass = 8Nm
moment due to second mass = 8Nm
d) total mass acting = 100g + 200g + 200g (of the disc) = 500g = 5N
Post by: Shogun on June 03, 2009, 04:21:16 pm
f=force and d=distance) the product must be same. (then only they are balanced i.e in equilibrium)
the distance are given for each hole to the pivot. so i recomend to take the first hole(with distance 4cm) and add mass 200g at one side of the pivot. and on the other side, add mass 100g on the second hole (with disatnce 8 cm from teh pivot)
but first convert the masses to forces by multiplying the mass into 10, so 200( convert this to killogram by deviding it by 1000 ) 0.2 x 10 u get 2
so when using the formula "fxd " u get on one side: 2x4=8Nm
and
on the other side: 1x8=8Nm
- see both have the same product so it is now they are balanced(in equilibrium)
ans2b) the disc does not move or rotate as u put the mass so they are balanced so no turning effect which means no moment.
c)use formula "fxd" but convert the mass in to force but multiplying them in to 10 and convert the mass to kg first
2x4=8Nm
1x8=8Nm
d)this is the force of pivot which is downwar to get tht simply add the masses u put
1+8=9N
but rmember u can choose any mass at any distance but the product with equation "fxd" must be same
thts all,hope this helped, any confusion or difficulties or help u need, im all here
Post by: Eamyzz on June 03, 2009, 04:22:31 pm
may someone answer this question
paper 3 oct/nov 2008 q (2) all please and :D thank you
thats easy
look first
a)
u no that moment=force * distance
so 4 instance i chose 200g and 100g
to make sure they both have da same moment
200*4=100*8
800=800
so that its at equilibrium
b)
It will stay stable which ensures that its at equilibrium.
c)
do the same thing i used to explain part a)
M1=200*10*4(*10 because its force and 200g is mass so *10 to make it weight)
m2=100*10*8
M1=M2
8000Nm=8000Nm
and the answer 4 da 2 blaks is 8000 or wateva accordind to ur chosen values
d) (200*10)+(100*10)+(200*10)
=5000N
i multiplies each one by 10 to make them forces
hope it helped :)
Post by: Shogun on June 03, 2009, 04:25:05 pm
so its 1+2+2=5N
i added wrong mass silly me..
Post by: Ghost Of Highbury on June 03, 2009, 04:25:49 pm
hello eamyzzmay someone answer this question
paper 3 oct/nov 2008 q (2) all please and :D thank you
thats easy
look first
a)
u no that moment=force * distance
so 4 instance i chose 200g and 100g
to make sure they both have da same moment
200*4=100*8
800=800
so that its at equilibrium
b)
It will stay stable which ensures that its at equilibrium.
c)
do the same thing i used to explain part a)
M1=200*10*4(*10 because its force and 200g is mass so *10 to make it weight)
m2=100*10*8
M1=M2
8000Nm=8000Nm
and the answer 4 da 2 blaks is 8000 or wateva accordind to ur chosen values
d) (200*10)+(100*10)+(200*10)
=5000N
i multiplies each one by 10 to make them forces
hope it helped :)
just need to confirm one thing
are u sure that the answer for d) is 5000N
if so plz explain me how..
if u read my answer i have written 5N
because 200 + 200 + 100 = 500g = 500/100 N = 5N
thanks
:)
Post by: sweetie on June 03, 2009, 04:26:07 pm
Post by: Ghost Of Highbury on June 03, 2009, 04:27:50 pm
2a) put different value of masses on bothe sides of the pivot but make sure tht after using the formula (fxd) (wherehow o u get the d) answer as "1+8"
f=force and d=distance) the product must be same. (then only they are balanced i.e in equilibrium)
the distance are given for each hole to the pivot. so i recomend to take the first hole(with distance 4cm) and add mass 200g at one side of the pivot. and on the other side, add mass 100g on the second hole (with disatnce 8 cm from teh pivot)
but first convert the masses to forces by multiplying the mass into 10, so 200( convert this to killogram by deviding it by 1000 ) 0.2 x 10 u get 2
so when using the formula "fxd " u get on one side: 2x4=8Nm
and
on the other side: 1x8=8Nm
- see both have the same product so it is now they are balanced(in equilibrium)
ans2b) the disc does not move or rotate as u put the mass so they are balanced so no turning effect which means no moment.
c)use formula "fxd" but convert the mass in to force but multiplying them in to 10 and convert the mass to kg first
2x4=8Nm
1x8=8Nm
d)this is the force of pivot which is downwar to get tht simply add the masses u put
1+8=9N
but rmember u can choose any mass at any distance but the product with equation "fxd" must be same
thts all,hope this helped, any confusion or difficulties or help u need, im all here
the masses chosen is 200g and 100g = 2N and 1N --> 3N + 2N(of the disc) = 5N
am i correct
i am not sure
plzz help
thank u :)
Post by: Eamyzz on June 03, 2009, 04:29:37 pm
hello eamyzzmay someone answer this question
paper 3 oct/nov 2008 q (2) all please and :D thank you
thats easy
look first
a)
u no that moment=force * distance
so 4 instance i chose 200g and 100g
to make sure they both have da same moment
200*4=100*8
800=800
so that its at equilibrium
b)
It will stay stable which ensures that its at equilibrium.
c)
do the same thing i used to explain part a)
M1=200*10*4(*10 because its force and 200g is mass so *10 to make it weight)
m2=100*10*8
M1=M2
8000Nm=8000Nm
and the answer 4 da 2 blaks is 8000 or wateva accordind to ur chosen values
d) (200*10)+(100*10)+(200*10)
=5000N
i multiplies each one by 10 to make them forces
hope it helped :)
just need to confirm one thing
are u sure that the answer for d) is 5000N
if so plz explain me how..
if u read my answer i have written 5N
because 200 + 200 + 100 = 500g = 500/100 N = 5N
thanks
:)
ya sure...look u didnt multiply the masses by 10 to make them forces
look this would b da answer if u did
=(200*10)+(200*10)+(100*10)
=2000+2000+1000
=5000N
thats all :)
if its still not clear dont hesitate to say it ;)
Post by: Shogun on June 03, 2009, 04:30:03 pm
Post by: Shogun on June 03, 2009, 04:31:37 pm
u must devide the mass by 1000 to convert them to killos THEN multiply them by 10, so u get
200/1000= 0.2kg
then 0.2kg x 10 = 2N
Post by: Ghost Of Highbury on June 03, 2009, 04:32:12 pm
whose giving me -rep for that
:(
@eamyzz...
100g = 1N
200g = 2N
i don't think u multiply it by 10..
plzz clear my doubt
thanks once again
Post by: Shogun on June 03, 2009, 04:33:55 pm
Post by: Ghost Of Highbury on June 03, 2009, 04:34:51 pm
am i correct
100g = 1N
therefore 200g = 2 N
?????
Post by: Eamyzz on June 03, 2009, 04:36:04 pm
umm eamyz u have to first devide them by 1000 cuz they are in grams
u must devide the mass by 1000 to convert them to killos THEN multiply them by 10, so u get
200/1000= 0.2kg
then 0.2kg x 10 = 2N
ooops another silly mistake Thanks so it will b
=(0.2 kg*10)=2N
=2N+2N+1N
5N
soo u r right Adi n i am wrong sorry :-[
Post by: Shogun on June 03, 2009, 04:37:09 pm
Post by: Eamyzz on June 03, 2009, 04:38:21 pm
Post by: Shogun on June 03, 2009, 04:38:36 pm
and really adi u got any doubts?
Post by: Ghost Of Highbury on June 03, 2009, 04:41:20 pm
thanks
anyway
i had just 1 doubt,,,
clarified now
thanks scholar
lol..
plzz stop -repping me
wat did i doooo??? :)
Post by: persian17 on June 03, 2009, 04:41:30 pm
Post by: Eamyzz on June 03, 2009, 04:42:06 pm
Post by: Shogun on June 03, 2009, 04:47:14 pm
Post by: Clem on June 03, 2009, 04:50:15 pm
Can someone help me with question 3 (b) June 07?
Why can't GPE be converted to kinetic energy and how does it get converted to heat?
Post by: Ghost Of Highbury on June 03, 2009, 04:50:22 pm
:)
Post by: Shogun on June 03, 2009, 04:52:51 pm
Post by: Eamyzz on June 03, 2009, 04:55:00 pm
Post by: Eamyzz on June 03, 2009, 04:56:41 pm
Post by: astarmathsandchemistry on June 03, 2009, 04:58:10 pm
Post by: Eamyzz on June 03, 2009, 04:59:53 pm
GUYS MY REP IS DECREAAAAASINGG!!!! :@ WHAT DID I DO!! :(
tell astarmathandphysics he will bring it bak to normal because -32 is rlly hard 4 us to bring bak ;D
Post by: astarmathsandchemistry on June 03, 2009, 05:01:06 pm
i did he is not relpying :sGUYS MY REP IS DECREAAAAASINGG!!!! :@ WHAT DID I DO!! :(
tell astarmathandphysics he will bring it bak to normal because -32 is rlly hard 4 us to bring bak ;D
Post by: Shogun on June 03, 2009, 05:02:02 pm
Post by: Eamyzz on June 03, 2009, 05:02:39 pm
i did he is not relpying :sGUYS MY REP IS DECREAAAAASINGG!!!! :@ WHAT DID I DO!! :(
tell astarmathandphysics he will bring it bak to normal because -32 is rlly hard 4 us to bring bak ;D
ok 4 nw i will do my bst i will +rep u evry 1 hour ;D
Post by: astarmathsandchemistry on June 03, 2009, 05:06:12 pm
Post by: Priceless on June 03, 2009, 05:08:08 pm
Post by: Ghost Of Highbury on June 03, 2009, 05:08:42 pm
Hey everyone!
Can someone help me with question 3 (b) June 07?
Why can't GPE be converted to kinetic energy and how does it get converted to heat?
the potential energy decreases as it changes to kinetic energy and heat energy...
Post by: Ghost Of Highbury on June 03, 2009, 05:09:07 pm
lol guyz.....i ll +rep all u guyz but seriously i thnk itz more imp dat v ans pplz doubts here.... :P......dont u thnk so?
agree
thanks for the rep
:D
Post by: Eamyzz on June 03, 2009, 05:11:13 pm
Post by: Priceless on June 03, 2009, 05:12:35 pm
Guys what is the difference b/w Flemings Left and right hand rule? when do you use each?
this is confusing but da diff is dat u use flemings right-hand rule wen u hv an induced current......just remb if ders a battery present ders no induced current so use left-hand rule but if der isnt a battery...den use da right-hand rule..
i hope u get it....all da best evry1 ;)
Post by: Shogun on June 03, 2009, 05:15:22 pm
Post by: Priceless on June 03, 2009, 05:18:41 pm
Hey everyone!
Can someone help me with question 3 (b) June 07?
Why can't GPE be converted to kinetic energy and how does it get converted to heat?
the potential energy decreases as it changes to kinetic energy and heat energy...
@adi: thnkz adi....n no need 4 thnkz ;) ....By the way adi dat wz clem's ques....actualy in da MS dey say dat u cant rite k.e...dey say all da p.e converts in2 heat energy....which i didnt evn understnd y ???...plzz help....thnkz in advance
@eamyzz: lol oh ok :D
@shogun: guyz plz no need 4 thnkz...v r helping each other here...ders absolutely no need 4 thnku...ok...Take care
all da best ppl! :)
Post by: Priceless on June 03, 2009, 05:19:32 pm
Post by: Ghost Of Highbury on June 03, 2009, 05:20:23 pm
i saw the markscheme
in these types of wierd questions
u need to be a little smart
wat u do is write all the possibilities like sound, heat, KE...etc..
they will ignore the ones not required and give u a mark for heat
!!!
:)
wierd examiners,,,lol..
Post by: Eamyzz on June 03, 2009, 05:21:17 pm
Guys what is the difference b/w Flemings Left and right hand rule? when do you use each?
this is confusing but da diff is dat u use flemings right-hand rule wen u hv an induced current......just remb if ders a battery present ders no induced current so use left-hand rule but if der isnt a battery...den use da right-hand rule..
i hope u get it....all da best evry1 ;)
may u plz elaborate it more****BLUSH***
but thnk yu
Post by: Eamyzz on June 03, 2009, 05:23:35 pm
Hey everyone!
Can someone help me with question 3 (b) June 07?
Why can't GPE be converted to kinetic energy and how does it get converted to heat?
the potential energy decreases as it changes to kinetic energy and heat energy...
@adi: thnkz adi....n no need 4 thnkz ;) ....By the way adi dat wz clem's ques....actualy in da MS dey say dat u cant rite k.e...dey say all da p.e converts in2 heat energy....which i didnt evn understnd y ???...plzz help....thnkz in advance
@eamyzz: lol oh ok :D
@shogun: guyz plz no need 4 thnkz...v r helping each other here...ders absolutely no need 4 thnku...ok...Take care
all da best ppl! :)
look it will b lost as heat due to da friction between da foot and da stairs it may also b lost as sound but mainly heat....hope it helped :)
Post by: Guthixol on June 03, 2009, 05:24:17 pm
i got anohter quesiton :P same paper 2008 oct nov q3 all of it xP really sorry
thanks
Post by: Eamyzz on June 03, 2009, 05:26:58 pm
hey its not me whos - reping you :P i increased the person who helped me :D thank you
i got anohter quesiton :P same paper 2008 oct nov q3 all of it xP really sorry
thanks
thats nt helpful...learn 4rm me +rep any1 u fynd wid low rep :D (A)
Post by: Ghost Of Highbury on June 03, 2009, 05:29:04 pm
okk heres ur answer
ai) pressure of a liquid = 10 * h * d(density of water)
= 10 * 70 * a050 = 7.35 * 10^5
ii) total pressure = pressure of water + atmospheric pressure => 735000 + 100000 = 835000
b) pressure = force / area
force = pressure * area
= 6.5 * 10^5 * 2.5 = 1625000N
c) as density is directly proportional to the pressure, the pressure on the submarine is less because the density of freseh water is less..
hope that helped
Post by: Shogun on June 03, 2009, 05:29:46 pm
Post by: Ghost Of Highbury on June 03, 2009, 05:30:34 pm
hey its not me whos - reping you :P i increased the person who helped me :D thank you
i got anohter quesiton :P same paper 2008 oct nov q3 all of it xP really sorry
thanks
answered ur question..
scroll up
:D
Post by: Shogun on June 03, 2009, 05:33:45 pm
cuz the question says "the energy transoformations" and the mark scheme avoids by saying tht the whole pe was changed to something, as it only said transformed or decreased...
and heat is a must, as heat is lost due to friction, as any waste enrgy is lost mostly by heat.
Post by: XGhostX on June 03, 2009, 05:36:26 pm
Post by: Eamyzz on June 03, 2009, 05:37:12 pm
hey its not me whos - reping you :P i increased the person who helped me :D thank you
i got anohter quesiton :P same paper 2008 oct nov q3 all of it xP really sorry
thanks
HERE U GO::::
a) i] = gravity* density*height
= 10*1050*70
= 735000Pa
= 7.35*10^5 Pa
ii] pressure found at i] + atmospheric pressure
=7.35*10^5 +1*10^5
=8.35*10^5
b) P=F/A
P=6.5*10^5
A=2.5
F= ?
F=6.5*10^5 *2.5
F=1.625*10^6
c) As there r less number of particles in da less dense water (fresh water)
HOPE IT HELPED =D
Post by: Shogun on June 03, 2009, 05:37:37 pm
Just here to say Good luck everyone ;D
u too ;D :D
Post by: Priceless on June 03, 2009, 05:37:51 pm
@eamyzz.....4 da ques concerning energy conversions....da MS also said 2 ignore sound....lol....just du wat adi said ;)
n abt da rulez....im confused 2 but i ll try 2 explain n any1 plz correct me if im wrong......
der r 3 things: movement(motion of wire), magnetic field n current.....if any 2 of dem r occuring, den da 3rd wud b produced.....like in a generator....da wire is moved n der r magnets creating a magnetic field.....so a current is generated while in a motor.....ders da current n magnetic field producing movement of wire
now in a generator u wud use da right-hand rule 2 work out any of da three bcuz da current is induced.....n in a motor u wud use da left-flemings rule(usually 2 find da direction)
motors n generators r just examples By the way so apply in similar types of diags of machines given.....
i hope u understud....adi n shogun or anybody plz correct me if im wrong....thnkz...Take care...all da best! ;)
Post by: Friends on June 03, 2009, 05:39:21 pm
IF I +REP REKO IT INCREASE BY 2(IT HAPPEN TO ALL MEMMBERS)
IF I -REP HIM IT DECREASE BY 2 OR 1
:D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D
Post by: Eamyzz on June 03, 2009, 05:40:56 pm
OK now this is weird.
IF I +REP REKO IT INCREASE BY 2(IT HAPPEN TO ALL MEMMBERS)
IF I -REP HIM IT DECREASE BY 2 OR 1
:D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D :D
did u try +reping me ;D :P
dnt wrry its normal they no u r jst 2 generous ;D
Post by: Priceless on June 03, 2009, 05:41:28 pm
lol, wierd, i think its cuz- not all energy is transformed to k.e, i dont think this goes like tht law of cnservation of falling bodies (where at falling ,some of it is ke and some of it is pe.)
cuz the question says "the energy transoformations" and the mark scheme avoids by saying tht the whole pe was changed to something, as it only said transformed or decreased...
and heat is a must, as heat is lost due to friction, as any waste enrgy is lost mostly by heat.
thnkz shogun but it getz confusing at tymes wat da xaminers want den...neway as adi said just rite all da appropiate answers...lol ;) n thnkz neway :)
@Guthixol: gud luck 2 u 2..hope da ppr goes well....*fingers crossed* ;) :D
Post by: Ghost Of Highbury on June 03, 2009, 05:47:16 pm
i gtg.,.
good luck for ur exams
my best wishes with u guys
hope u all do extremely well..
bye .
gud night,, :)
Post by: Bani on June 03, 2009, 05:47:50 pm
and please explain me why...the answer is what it is...
Thanks in advance...
Post by: Eamyzz on June 03, 2009, 05:49:43 pm
okk...guys
i gtg.,.
good luck for ur exams
my best wishes with u guys
hope u all do extremely well..
bye .
gud night,, :)
good luck 2 ....enjoy ur """SLEEP"" :D :P
Post by: Priceless on June 03, 2009, 05:52:32 pm
okk...guys
i gtg.,.
good luck for ur exams
my best wishes with u guys
hope u all do extremely well..
bye .
gud night,, :)
ok adi....Take care n i no u dnt hv xams but still all da luck 4 evrythng u du.....n thnkz 4 da wishes.....
my wishes r alwayz wid evry1 n hope evry1 duz xtremely well...
Take care n gud nyt....sweet dreams! ;) :)
Post by: Shogun on June 03, 2009, 05:53:55 pm
okk...guys
i gtg.,.
good luck for ur exams
my best wishes with u guys
hope u all do extremely well..
bye .
gud night,, :)
bye m8, hope we all we do well :D
Post by: Eamyzz on June 03, 2009, 05:54:35 pm
okk...guys
i gtg.,.
good luck for ur exams
my best wishes with u guys
hope u all do extremely well..
bye .
gud night,, :)
ok adi....Take care n i no u dnt hv xams but still all da luck 4 evrythng u du.....n thnkz 4 da wishes.....
my wishes r alwayz wid evry1 n hope evry1 duz xtremely well...
Take care n gud nyt....sweet dreams! ;) :)
i ddnt no that u arent taking physics anway gd luck in ur other subjects have a nighty :D
Post by: Priceless on June 03, 2009, 05:56:23 pm
gud luck eamyzz 4 tom! ;)
Post by: Shogun on June 03, 2009, 05:58:05 pm
summer or winter,lol
Post by: Bani on June 03, 2009, 05:59:54 pm
P.S just reminding cuz I think no one noticed my question :D
Post by: gonnagetana on June 03, 2009, 06:01:14 pm
Post by: Priceless on June 03, 2009, 06:05:48 pm
Please someone help. Could you please attach the drawing of part b), Q10, paper October/November 2007.
and please explain me why...the answer is what it is...
Thanks in advance...
lol....i myself am not sure abt da answer actualy.....n wud hv scanned wat i thnk is rite but scanner is in parents room n dads using it....sory....can sum1 plz help! :)
Post by: asus on June 03, 2009, 06:12:26 pm
Post by: 12345abc on June 03, 2009, 06:14:16 pm
Post by: goin4dakill on June 03, 2009, 06:18:08 pm
how do we draw a NOT gate? ???
NOT GATE: triangle
AND GATE: up side down cup
OR GATE: like a missile
Anything with N in the front, is opposite and drawn the same :)
I'll give u a kiss if u rep+ me :D
Post by: gonnagetana on June 03, 2009, 06:19:37 pm
can anyone plz explain the spontaneous nature of radiation??? QUICKLY PLZ!!!
radiation occurs naturally over space and time. the is no way to tell which particles will emit radiation in a sample.its totally random
Post by: Kim on June 03, 2009, 06:23:08 pm
how do we draw a NOT gate? ???a NOT gate is a triangle with a small circle in front with 1 input and 1 output
Post by: asus on June 03, 2009, 06:24:22 pm
how do we draw a NOT gate? ???a NOT gate is a triangle with a small circle in front with 1 input and 1 output
this one is the best..
+rep for u & goin4dakill
Post by: .... on June 03, 2009, 06:25:05 pm
can someone help??? in the syllabus, it says, for the magnetic effect of a current, "state the qualitative variation of the strength of the magnetic feild over salient parts of the pattern" (4.5 d) what does that mean??
this just means, that, for example, a wire with current has a magnetic field, the further away you go from the wire, the weaker the magnetic field becomes..such a question is in june 2003..do check it out..
Post by: 12345abc on June 03, 2009, 06:26:31 pm
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
___________________________________
___________________________________
ooooooooooooooooooooooooooooooooooo
o-out of paper
x-into paper
_- cardboard
Post by: dreams24 on June 03, 2009, 06:26:52 pm
can someone help??? in the syllabus, it says, for the magnetic effect of a current, "state the qualitative variation of the strength of the magnetic feild over salient parts of the pattern" (4.5 d) what does that mean??
this just means, that, for example, a wire with current has a magnetic field, the further away you go from the wire, the weaker the magnetic field becomes..such a question is in june 2003..do check it out..
even i was looking for that..thanks!
Post by: Aodian on June 03, 2009, 06:27:45 pm
Post by: Kim on June 03, 2009, 06:28:24 pm
THANX...another problem...how do we draw field lines on this:i cant understand ur question
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
___________________________________
___________________________________
ooooooooooooooooooooooooooooooooooo
o-out of paper
x-into paper
_- cardboard
Post by: goin4dakill on June 03, 2009, 06:28:35 pm
I also have to study for lit as well..as you prob all do as well.. but i was wondering.
What is the hardest past paper, in ur opinion?!?! SO i can do it?
Post by: .... on June 03, 2009, 06:29:18 pm
Uhmmm, guyssss!
I also have to study for lit as well..as you prob all do as well.. but i was wondering.
What is the hardest past paper, in ur opinion?!?! SO i can do it?
most of the latest papers were quite hard, according to me, may/june 2007..dunno about everyone else
Post by: Kim on June 03, 2009, 06:34:47 pm
hmm can someone tell me how to answer the whole of question nine in m/j07.. i got the mark schemes but they're vague.. to me at least.. :P thanx for the help again!well i cant help u wid 9 a and b cause i just copied the ms ::)
c- u jus draw the dc motor
d-after each half turn the current passes from one split ring to another in the opposite direction.this ensures continuous rotating of the coil
Post by: 12345abc on June 03, 2009, 06:36:52 pm
THANX...another problem...how do we draw field lines on this:i cant understand ur question
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
___________________________________
___________________________________
ooooooooooooooooooooooooooooooooooo
o-out of paper
x-into paper
_- cardboard
ok so u see,there is this cardboard and then there is this coil wound around it in the way shown...we have to draw the magnetic field pattern...i saw this in the may/june 2007 physics paper 2 for cie o'levels...
Post by: devileye on June 03, 2009, 06:37:08 pm
Post by: .... on June 03, 2009, 06:38:31 pm
hmm can someone tell me how to answer the whole of question nine in m/j07.. i got the mark schemes but they're vague.. to me at least.. :P thanx for the help again!well i cant help u wid 9 a and b cause i just copied the ms ::)
c- u jus draw the dc motor
d-after each half turn the current passes from one split ring to another in the opposite direction.this ensures continuous rotating of the coil
for 9a..its mainly the normal explanation, that, when a current-carrying conductor, is placed in a magnetic field, it experinces a force due to the magnetic field due to the magnet and magnetic field due to current coinciding..
for b, since its the motor effect..we use flemings left hand rule...first finger, from N to S, middle finger, from + to -..and thumb gives the force, which is anticlockwise..
Post by: Kim on June 03, 2009, 06:41:33 pm
hey...cn sum1 plzzzz explain eddy currents?? and hw they wrk..and the lenz law.....plz urgent!!!!asap :-\eddy currents happen in a transformer
it is the leakage of current in the iron core of the transformer it happens because iron is a good conductor of electricity to reduse it the iron core is laminated into thin sheets
Post by: goin4dakill on June 03, 2009, 06:42:36 pm
Okay, i have some very important advice- thats a secret. So dont tell anyone!!!!!!!!!!! ha. Plus points there..hahah
DESPITE THE FACT THAT I AM NOT TELLING A STUDENT FORUM FULL OF THOUSANDS OF PEOPLE!
ANyway, So for the paper 6..the night before I did a past paper 2006 june. The first three questions in teh 2009 paper, were exactly the same. And i mean EEEZACTLY.
So, according to my calculations (inhaler, push glasses up nose, haha dork attack) umm, they might base paper 3 from June 2006 as well.
If you have an inhaler- umm I was kiddinggggg - i love people with inhalers :D <3
Post by: nid404 on June 03, 2009, 06:43:14 pm
here https://studentforums.biz/index.php/topic,1798.315.html
Post by: devileye on June 03, 2009, 06:43:35 pm
Post by: Kim on June 03, 2009, 06:44:14 pm
Heyyy Guys!haha i guess i will do it or half way memorize dat paper then!(and dork attack?funny)
Okay, i have some very important advice- thats a secret. So dont tell anyone!!!!!!!!!!! ha. Plus points there..hahah
DESPITE THE FACT THAT I AM NOT TELLING A STUDENT FORUM FULL OF THOUSANDS OF PEOPLE!
ANyway, So for the paper 6..the night before I did a past paper 2006 june. The first three questions in teh 2009 paper, were exactly the same. And i mean EEEZACTLY.
So, according to my calculations (inhaler, push glasses up nose, haha dork attack) umm, they might base paper 3 from June 2006 as well.
If you have an inhaler- umm I was kiddinggggg - i love people with inhalers :D <3
Post by: Kim on June 03, 2009, 06:45:08 pm
hmm....thx but hw are they produced...and wat do they do..????wat's there role.. ???are u talkin about eddy currents?
Post by: 12345abc on June 03, 2009, 06:46:01 pm
Post by: nid404 on June 03, 2009, 06:46:43 pm
hmm....thx but hw are they produced...and wat do they do..????wat's there role.. ???the law says that the induced current is such as to oppse the change causing it(electromagnetic induction)
ppt's good ull get it
Post by: Kim on June 03, 2009, 06:48:50 pm
oh and can u also plz explain the purpose of split ring in dc motor and slip rings in ac generator???they both have the same function
they connect the coil with the circuit so that currnet can flow through
or in other words after every half turn the current passes from one ring to the other around the coil in the opposite direction.this ensures continuous rotation of the coil
Post by: Aodian on June 03, 2009, 06:50:50 pm
hmm can someone tell me how to answer the whole of question nine in m/j07.. i got the mark schemes but they're vague.. to me at least.. :P thanx for the help again!well i cant help u wid 9 a and b cause i just copied the ms ::)
c- u jus draw the dc motor
d-after each half turn the current passes from one split ring to another in the opposite direction.this ensures continuous rotating of the coil
for 9a..its mainly the normal explanation, that, when a current-carrying conductor, is placed in a magnetic field, it experinces a force due to the magnetic field due to the magnet and magnetic field due to current coinciding..
for b, since its the motor effect..we use flemings left hand rule...first finger, from N to S, middle finger, from + to -..and thumb gives the force, which is anticlockwise..
ah okay.. that means the current is cutting the magnetic field and current is induced in it rite?? its got to do with induction?
Post by: Eamyzz on June 03, 2009, 06:51:25 pm
PLEASE REPLY FAST ;D
Post by: devileye on June 03, 2009, 06:55:23 pm
Post by: Kim on June 03, 2009, 06:56:20 pm
wat is da difference By the way motors and generators and da uses simply evrythng ?dc motor
PLEASE REPLY FAST ;D
supplied with dc current
changes electrical to motion energy
the outside circuit is connected to a battery switch or rheostat
its brushes touch two halves of a commutator
Ac motor
supplied with ac current
changes motion to electrical
outside circuit is connected to lamp or voltmeter
its brushes touch 2 separate split rings
Post by: goin4dakill on June 03, 2009, 06:58:20 pm
Heyyy Guys!
Okay, i have some very important advice- thats a secret. So dont tell anyone!!!!!!!!!!! ha. Plus points there..hahah
DESPITE THE FACT THAT I AM NOT TELLING A STUDENT FORUM FULL OF THOUSANDS OF PEOPLE!
ANyway, So for the paper 6..the night before I did a past paper 2006 june. The first three questions in teh 2009 paper, were exactly the same. And i mean EEEZACTLY.
So, according to my calculations (inhaler, push glasses up nose, haha dork attack) umm, they might base paper 3 from June 2006 as well.
If you have an inhaler- umm I was kiddinggggg - i love people with inhalers :D <3
Just so everyone gets to seeee
Post by: Kim on June 03, 2009, 07:01:36 pm
so best of luck to all of you :D bye
Post by: esso on June 03, 2009, 07:05:00 pm
Post by: Ghost Of Highbury on June 03, 2009, 07:07:00 pm
Post by: sweetie on June 03, 2009, 07:19:51 pm
resistance= constant x length/ cross- sectional area
plzzzzz reply quick
thanx
Post by: MaNa on June 03, 2009, 07:20:22 pm
Post by: AS girl on June 03, 2009, 07:21:48 pm
GUys can anyoone tell me how much u needa get in paper 3 to get an A*
It depends on the curve!! If the curve is low this year (hope so) u can get an A* with no effort!
Post by: Eamyzz on June 03, 2009, 07:22:27 pm
wat is da difference By the way motors and generators and da uses simply evrythng ?dc motor
PLEASE REPLY FAST ;D
supplied with dc current
changes electrical to motion energy
the outside circuit is connected to a battery switch or rheostat
its brushes touch two halves of a commutator
Ac motor
supplied with ac current
changes motion to electrical
outside circuit is connected to lamp or voltmeter
its brushes touch 2 separate split rings
thank u u r an angel u deserve a +rep ;)
Post by: MaNa on June 03, 2009, 07:23:48 pm
i mean like averageGUys can anyoone tell me how much u needa get in paper 3 to get an A*
It depends on the curve!! If the curve is low this year (hope so) u can get an A* with no effort!
Post by: Eamyzz on June 03, 2009, 07:25:14 pm
Post by: MaNa on June 03, 2009, 07:25:48 pm
manah and Ig grl i love ur pictures...they r so WOOOOOW :o ;)thankyou :)
Post by: care on June 03, 2009, 07:26:02 pm
Post by: sweetie on June 03, 2009, 07:26:08 pm
wat is da constant inplzzzzzzz i need an answer
resistance= constant x length/ cross- sectional area
plzzzzz reply quick
thanx
Post by: care on June 03, 2009, 07:27:10 pm
Post by: MaNa on June 03, 2009, 07:27:44 pm
constant is the densitywat is da constant inplzzzzzzz i need an answer
resistance= constant x length/ cross- sectional area
plzzzzz reply quick
thanx
Post by: sweetie on June 03, 2009, 07:27:51 pm
Post by: MaNa on June 03, 2009, 07:28:58 pm
doesnt have a value????????it sure does its always given in the question
cuz its the density ofthe wire which they dont expect u to know
i dont think they have ever bring such eq.
Post by: Ghost Of Highbury on June 03, 2009, 07:29:59 pm
it is called the resistivity for the material
R = k*l / a
the resistivities of metals increase at high. temperatures, for most other materials
it decreases
:)
don't worry u don't need to know the value
Post by: AS girl on June 03, 2009, 07:30:29 pm
manah and Ig grl i love ur pictures...they r so WOOOOOW :o ;)
Thanks..i like ur pic 2-it's from legally blonde 1 right? I watched this movie like 5 times and never got bored from it!
Post by: MaNa on June 03, 2009, 07:30:59 pm
can someone explain me the difference between virtual and real image?real image is foremed when all the ray frm a pont on an object are brought togeth again to another point
the real image can be seen in the screen
virtual image is formed where the virtual rays appear to come from when a screen is placed no image are formed
Post by: care on June 03, 2009, 07:31:27 pm
and it's not the density of the material!
Post by: Ghost Of Highbury on June 03, 2009, 07:32:14 pm
can someone explain me the difference between virtual and real image?a real image is one which can be produced on a screen and is formed by rays that actually pass through it
a virtual image cannot be formed on a screen, rays appear to come from the ray but actually don't.
:)
Post by: annie_angel on June 03, 2009, 07:32:58 pm
can someone explain me the difference between virtual and real image?virtual image-->cannot be obtained on screen
real image-->can be obtained on screen
hope this helps:)
Post by: Ghost Of Highbury on June 03, 2009, 07:33:08 pm
not density
good luck
Post by: MaNa on June 03, 2009, 07:33:33 pm
http://en.wikipedia.org/wiki/Electrical_resistance#Resistance_of_a_conductor
and it's not the density of the material!
oh yaa ma badd i looked throgh the pymbol which was like density one =? its resistivity :)
Post by: sweetest angel on June 03, 2009, 07:34:52 pm
please anyone?
the markscheme xplains ntin' 'n its so hard ='(
any help is most appreciated
Post by: MaNa on June 03, 2009, 07:35:17 pm
n do u have any prediction abt the topics?
Post by: AS girl on June 03, 2009, 07:37:07 pm
GUYS AVERAGE MARKS FOR AN A*
n do u have any prediction abt the topics?
Have no prediction for the average mark :(
Post by: annie_angel on June 03, 2009, 07:38:39 pm
november 1999 Q3 (a)my teacher said tht we need to practise from 2000-2008 nov and may...cuz back in 1990-1999 da syllabus waz different...
please anyone?
the markscheme xplains ntin' 'n its so hard ='(
any help is most appreciated
Post by: Eamyzz on June 03, 2009, 07:39:00 pm
manah and Ig grl i love ur pictures...they r so WOOOOOW :o ;)
Thanks..i like ur pic 2-it's from legally blonde 1 right? I watched this movie like 5 times and never got bored from it!
Thanks 2 u and 2 manah and ya its 4rm legally blonde am addicted 2 dat film i watched over 7 tyms and still nt bored 4rm it....its freaky as i am starting 2 act like her :o
and evry1 noticed this even ma english teacher says am a copy of her it even reflects on ma writings :o
By the way am also a pink freak r u ?
am a chatterbox we bttr get bak 2 physics ;D
Post by: Eamyzz on June 03, 2009, 07:41:10 pm
november 1999 Q3 (a)my teacher said tht we need to practise from 2000-2008 nov and may...cuz back in 1990-1999 da syllabus waz different...
please anyone?
the markscheme xplains ntin' 'n its so hard ='(
any help is most appreciated
ya u r right thats wat ma teacher told me 2 :)
Post by: Ghost Of Highbury on June 03, 2009, 07:43:14 pm
november 1999 Q3 (a)may/june or oct/nov
please anyone?
the markscheme xplains ntin' 'n its so hard ='(
any help is most appreciated
Post by: MaNa on June 03, 2009, 07:44:01 pm
its novemebernovember 1999 Q3 (a)may/june or oct/nov
please anyone?
the markscheme xplains ntin' 'n its so hard ='(
any help is most appreciated
it says:)
Post by: Ghost Of Highbury on June 03, 2009, 07:44:51 pm
feeling sleepy rite now
its midnight over here,
lol
:)
Post by: MaNa on June 03, 2009, 07:47:23 pm
oops sorry..why where do u live?
feeling sleepy rite now
its midnight over here,
lol
:)
pakistan
Post by: Ghost Of Highbury on June 03, 2009, 07:50:05 pm
Post by: Ghost Of Highbury on June 03, 2009, 07:53:38 pm
it is a wierd question
but i have tried to solve it
is the answer 160 degree
i am not sure
plz chk it and do inform me..
if not
tell me the answer
i'll try n figure out
thanks :)
Post by: Eamyzz on June 03, 2009, 07:59:43 pm
Post by: Ghost Of Highbury on June 03, 2009, 08:02:40 pm
try sweetsh angel's question
find it attached
Post by: 12345abc on June 03, 2009, 08:03:39 pm
Post by: Ghost Of Highbury on June 03, 2009, 08:06:49 pm
it allows the current to pass through..until the switch is pressed continuously
a normally open switch is the opposite of that
it prevents current to pass through when pressed..and when not pressed prevents current
like the ones used in those pain relief heaters..
it starts heating when u continuousy press the switch ,when it gets too hot, u release the switch///
Post by: reishamix on June 03, 2009, 08:08:33 pm
n which years de hardest??
Post by: care on June 03, 2009, 08:08:55 pm
okk...good idea
try sweetsh angel's question
find it attached
i think it's 170°
Post by: Ghost Of Highbury on June 03, 2009, 08:09:58 pm
???no idea
difficult..
Post by: Ghost Of Highbury on June 03, 2009, 08:10:43 pm
wht papers shud i do ryt now??do 2006 and 1993,4, papers
n which years de hardest??
difficult ones,,
good luck
:)
Post by: reishamix on June 03, 2009, 08:12:06 pm
wht papers shud i do ryt now??do 2006 and 1993,4, papers
n which years de hardest??
difficult ones,,
good luck
:)
Thanks
;D
Post by: care on June 03, 2009, 08:12:18 pm
Post by: Ghost Of Highbury on June 03, 2009, 08:13:40 pm
i got 160
i guess ur way is correct
do u have the markscheme??
i dont
:-\
Post by: goin4dakill on June 03, 2009, 08:16:39 pm
I have a question..
If they ask you to draw a DC motor??? HOW?? My book doesnt have it..
and and AC MOTOR? what id they ask us that..its realy comlicated..what with the split ring commutators and all. HELP EEK!
Post by: Eamyzz on June 03, 2009, 08:17:01 pm
Post by: care on June 03, 2009, 08:17:06 pm
Post by: Ghost Of Highbury on June 03, 2009, 08:20:16 pm
yuppee..
i was correct
lol..
find the answer attached
(not sure)
:)
Post by: care on June 03, 2009, 08:21:32 pm
Post by: goin4dakill on June 03, 2009, 08:24:49 pm
How do u draw a dc motor..
and ac motor?
Post by: Ghost Of Highbury on June 03, 2009, 08:25:19 pm
OMG GUYS URGENTLY!!!!!!!!
I have a question..
If they ask you to draw a DC motor??? HOW?? My book doesnt have it..
and and AC MOTOR? what id they ask us that..its realy comlicated..what with the split ring commutators and all. HELP EEK!
my book has it
the drawing of dc motor
but unfortunately my scanner is not functioning
if u use tom duncan physics
chk out pg 221
--
well i can provide u with the text though
heres it
a simple dc motor consists of a rectangular coil of wire mounted on an axle which can rotate between the poles of a C-shaped magnet, each end of the coil is connected to half of a split ring of copper, called a commutator.
which rotates with the coil
two carbon blocks the brushes are perssed lightly against the sommutatoor by springs. the brushes are connected to an electric supply.
:)
find the image in google images
good luck
http://cache.eb.com/eb/image?id=63375&rendTypeId=4
Post by: Ghost Of Highbury on June 03, 2009, 08:28:55 pm
but chk out wikipedia
i got a note on motors
maybe it will help u
good luck
:)
Post by: goin4dakill on June 03, 2009, 08:29:43 pm
OMG GUYS URGENTLY!!!!!!!!
I have a question..
If they ask you to draw a DC motor??? HOW?? My book doesnt have it..
and and AC MOTOR? what id they ask us that..its realy comlicated..what with the split ring commutators and all. HELP EEK!
my book has it
the drawing of dc motor
but unfortunately my scanner is not functioning
if u use tom duncan physics
chk out pg 221
--
well i can provide u with the text though
heres it
a simple dc motor consists of a rectangular coil of wire mounted on an axle which can rotate between the poles of a C-shaped magnet, each end of the coil is connected to half of a split ring of copper, called a commutator.
which rotates with the coil
two carbon blocks the brushes are perssed lightly against the sommutatoor by springs. the brushes are connected to an electric supply.
:)
find the image in google images
good luck
http://cache.eb.com/eb/image?id=63375&rendTypeId=4
YOUR A LEGEND. full stop :)
Post by: Ghost Of Highbury on June 03, 2009, 08:30:41 pm
Post by: sweetest angel on June 03, 2009, 08:30:48 pm
hey sweetsh angellits 160
it is a wierd question
but i have tried to solve it
is the answer 160 degree
i am not sure
plz chk it and do inform me..
if not
tell me the answer
i'll try n figure out
thanks :)
says so in markscheme
Thanks for da pic attached for the answer bt if u can xaplain y u took those angles =/
i drew a common strait line for the points 'n found out that they were 5 dergrees lesser so 85-5=80 and 80+80=160 can we tke it dat way or can u plz xplain how u got it
plus the question says calculate not find out so can we still use the diagram?? ???
Thanks ;D
Post by: Ghost Of Highbury on June 03, 2009, 08:35:17 pm
let the intersection point be called X
PQX is a straight line
<RQX = 180 - <PQN - <NQR = 10 degree
same for the other side
therefore <XRQ = <RQX = 10 degree
angle sum property of triangles = add up to 180
therefore <QXR (the question) = 180 - 10 -10 =160
hope it helped
:)
Post by: Eamyzz on June 03, 2009, 08:38:18 pm
look at the image\
let the intersection point be called X
PQX is a straight line
<RQX = 180 - <PQN - <NQR = 10 degree
same for the other side
therefore <XRQ = <RQX = 10 degree
angle sum property of triangles = add up to 180
therefore <QXR (the question) = 180 - 10 -10 =160
hope it helped
:)
ya it definitely did u r a saint :)
Post by: sweetest angel on June 03, 2009, 08:39:09 pm
amazin' gentlemen we got an einstein rit here :P
Thanks Thanks 'n gud luk tom ;D
Post by: Ghost Of Highbury on June 03, 2009, 08:41:56 pm
i am 1 year younger to u guys
thatsy i am not appearing for my exams in may/june
i have my exams during oct/nov 2009
lol..
c ya
gud night
good luck
Post by: Eamyzz on June 03, 2009, 08:44:44 pm
Post by: reishamix on June 03, 2009, 08:56:11 pm
how do u define
split rings commutators?
Post by: Ghost Of Highbury on June 03, 2009, 08:58:41 pm
A slipring is a conductive ring - usually solid - on which a conductive brush/contact rides so as to complete a circuit even as the ring turns.
chk out this website
great website
http://www.gcsescience.com/pme13.htm
Post by: MaNa on June 03, 2009, 08:59:11 pm
hey guysallows the transfer of the alternating e.m.f induced in the rotating coil to the xternal circuit
how do u define
split rings commutators?
Post by: junky demon on June 03, 2009, 09:00:27 pm
this chapter is dam annoying for me..
i really cnt understnd ..
if ne 1s gt ne notes or cud explain it to me ,its ol fyn..
Thanks alot for ur tym..appreciated n gud fo tomo:D
Post by: junky demon on June 03, 2009, 09:02:19 pm
Post by: Ghost Of Highbury on June 03, 2009, 09:05:49 pm
could sum1 plz brief me abt wot i need to no for the topic cathode-ray tube..well! i have some really good website for that
this chapter is dam annoying for me..
i really cnt understnd ..
if ne 1s gt ne notes or cud explain it to me ,its ol fyn..
Thanks alot for ur tym..appreciated n gud fo tomo:D
howstuffworks - http://electronics.howstuffworks.com/tv3.htm
definitions, history etc - http://inventors.about.com/od/cstartinventions/a/CathodeRayTube.htm
good luck
:)
Post by: reishamix on June 03, 2009, 09:10:04 pm
hey guysallows the transfer of the alternating e.m.f induced in the rotating coil to the xternal circuit
how do u define
split rings commutators?
Thanks :)
Post by: Eamyzz on June 03, 2009, 09:13:31 pm
Post by: Ghost Of Highbury on June 03, 2009, 09:14:07 pm
new topic made
thank u
:D
Post by: junky demon on June 03, 2009, 09:15:03 pm
wot i mean is those plates and the heating filamint etc how does it ol work ???
and Thanks a lot atleast i gt a picture of wot it is :D
Post by: Aodian on June 03, 2009, 09:19:26 pm
Post by: junky demon on June 03, 2009, 09:25:10 pm
datz ol yu need to no and do the not gate wen applied to other gates well..correct me if im mistaken.. ;)
Post by: Eamyzz on June 03, 2009, 09:29:33 pm
Post by: Aodian on June 03, 2009, 09:30:05 pm
Juz remem wot does each gate do to the input values for eg.If its an AND gate and the input values are 0 1 thn the result wud be..0'thanx alot..
datz ol yu need to no and do the not gate wen applied to other gates well..correct me if im mistaken.. ;)
Post by: Priceless on June 03, 2009, 09:34:16 pm
may i have a summary of da electricity chapter ...pin points :)
check out this topic on SF itself....it has notes.....gud luck...Take care ;)
https://studentforums.biz/index.php/topic,2342.0.html
Post by: Eamyzz on June 03, 2009, 09:43:54 pm
may i have a summary of da electricity chapter ...pin points :)
check out this topic on SF itself....it has notes.....gud luck...Take care ;)
https://studentforums.biz/index.php/topic,2342.0.html
i donno hw to thank u....u r so.. soo....yaay...HELPFUL ;D
srry donnno wat 2 say literally
thanks again again and again
Post by: Priceless on June 03, 2009, 09:56:04 pm
Post by: Eamyzz on June 03, 2009, 09:59:34 pm
lol eamyzz.....i understand completely...but plz dont say thnku...dat 2 sooo many tymes.....v r here 2 help each other n dats xactly wat im doin....i presume u found da notes helpful...glad 2 no..Take care n all da best! ;)
shokran :D :P
ya they really helpful +rep ;)
but lsn do u no a nother good link 4 transformers, ac generators and dc motors summary ?
Post by: sweetsh on June 03, 2009, 10:00:53 pm
Post by: Priceless on June 03, 2009, 10:02:32 pm
Post by: Priceless on June 03, 2009, 10:03:38 pm
all da best 2 u all! ;)
Post by: Priceless on June 03, 2009, 10:08:04 pm
Post by: Eamyzz on June 03, 2009, 10:19:27 pm
Post by: shafiq_92libra on June 04, 2009, 04:11:44 am
Post by: hmh on June 04, 2009, 04:12:18 am
Hey guyz im gona go giv da physics exam. Wish me luck ;D I hope its easy and good luck 2 all of you ;D
GUD LUCKKKKKKKKKKKKKKKK !!!!!!!!!!!!!!!!!!!!
Post by: devileye on June 04, 2009, 05:11:57 am
Post by: bball92 on June 04, 2009, 05:18:20 am
did cambridge like change it like they did chemistry?
Post by: ~M.J~ on June 04, 2009, 05:26:34 am
Post by: hmh on June 04, 2009, 05:28:24 am
hey guys any advices for the paper
i think most important and every year's bit is motors and electricity.. so be well in tht and its rest mostly calculations.. so equations.. jst look over them.. if u need they r all here >> https://studentforums.biz/index.php/topic,2342.0.html
thts it really. GUD LUCK :)
Post by: susman on June 04, 2009, 05:38:09 am
Post by: devileye on June 04, 2009, 06:09:08 am
Post by: cashem'up on June 04, 2009, 06:13:18 am
Post by: trademarkq8 on June 04, 2009, 06:15:08 am
Post by: unknown on June 04, 2009, 07:19:52 am
Post by: nid404 on June 04, 2009, 07:27:04 am
Post by: esso on June 04, 2009, 07:59:56 am
Post by: Sasha on June 04, 2009, 08:18:41 am
Post by: MaNa on June 04, 2009, 08:22:29 am
ure decreasing the marking if it tunrs easy for other then getting A or A* would be hard
so just SHUSH!
Post by: IGSTUDENT on June 08, 2009, 08:50:14 am
hey guys any advices for the paper
i think most important and every year's bit is motors and electricity.. so be well in tht and its rest mostly calculations.. so equations.. jst look over them.. if u need they r all here >> https://studentforums.biz/index.php/topic,2342.0.html
thts it really. GUD LUCK :)
NOVEMBER 1993 PAPER1 Q19 .
I HAVE A DOUBT.
AS PER ME THE ANSWER SHOULD BE DIAGRAM C BUT IN MARK SCHEME IT IS DIAGRAM"D' .ABOUT DIFFRACTION OF WATER WAVES IN A WIDE GAP.
CAN U HELP AND TELL ME WHICH IS THE CORRECT ANSWER?
Post by: astarmathsandphysics on June 08, 2009, 08:54:05 am
hey guys any advices for the paper
i think most important and every year's bit is motors and electricity.. so be well in tht and its rest mostly calculations.. so equations.. jst look over them.. if u need they r all here >> https://studentforums.biz/index.php/topic,2342.0.html
thts it really. GUD LUCK :)
NOVEMBER 1993 PAPER1 Q19 .
I HAVE A DOUBT.
AS PER ME THE ANSWER SHOULD BE DIAGRAM C BUT IN MARK SCHEME IT IS DIAGRAM"D' .ABOUT DIFFRACTION OF WATER WAVES IN A WIDE GAP.
CAN U HELP AND TELL ME WHICH IS THE CORRECT ANSWER?
I dont have the paper. Only the ms. Can you post the paper?
Post by: IGSTUDENT on June 08, 2009, 08:57:03 am
-HERE IS THE LINK
Post by: IGSTUDENT on June 08, 2009, 10:14:30 am
Why is stage "A" the correct answer.
Pls could you explain!
Post by: nid404 on June 08, 2009, 07:21:31 pm
Post by: IGCSE hater! on June 08, 2009, 08:39:27 pm
Post by: 7ooD on June 08, 2009, 09:54:13 pm
Post by: angell on June 08, 2009, 10:00:30 pm
Q.6,7,11,19,32,33 - June 2000
and
Q.3,4,9,24,37 - Nov 2000
please help! i know the correct answer, i just wanna know WHY :S
Post by: 7ooD on June 08, 2009, 10:41:04 pm
Q 3 constant speed means same speed so a straight line that is parallel to the x axis which should be C
Q 4 acceleration can be found by the equation of V-U so here the V which is the final velocity is 150 and U the initial velocity is 50 so acceleration is 100
question 6 bathroom scales and force meter and top-pan balance all depend on the force of gravity but for beam balance the unknown mass in one pan is balanced against known masses in the other pan
Q7 easy the beaker mass is 100 g and the beaker+water is 140 g so the mass of the water is 140-100 and apply the equation mass=density*volume to get the density
Q 9 take this rule in mind whenever the effort or force or weight is away from the pivot it means it is less than the other force on the other pivot therefore less effort in the longest and furtherst from the pivot which is at D
Q 11 they use the concept of pressure in liquids to convert it into electrical energy so they choose D because the more the depth of liquid the more the pressure that water flows faster and thus the turbine rotates faster giving more output so at D it is at more depths than A and B and water level is less so greater tide but if it was at C the water level on the other side is more which doesn't generate more tide than D
Q 19 warm water is less dense so rises up and cold water is more dense and thus sinks which is true for convection in air hot air rises and cold air sinks
Q 24 sound doesn't travel in vaccum and thus window x is better at stopping sound because it has vaccum
Q 32 the live wire is directly taken from the station and is the one which supplys the lamp but the neutral wire is an extra wire which just is used to complete the circuit and also to give current to other equipment so putting a fuse over there won't help when the current is too high or to prevent electrical shock when the lamp is broken as the live is still on
Q 33
the cable becomes hot and melts because the lamp uses a wire that takes less current but when the same wire is used for the kettle it has more current thus more heat so it will become hot and melts
Q 37 the light dependent resistor depends on light the higher the light lower the resistance lower the light higher the resistance
Post by: 7ooD on June 08, 2009, 10:41:43 pm
Post by: IGSTUDENT on June 09, 2009, 04:33:04 am
lol,man now u tellin meHi Shogun
anywayz post em here,wanna know more
can u help out in November 1995 PAPer1 q.32
Post by: nid404 on June 09, 2009, 05:37:49 am
cuz the magnetic field lines have to be cut for a p.d to be induced.
Post by: IGSTUDENT on June 09, 2009, 06:03:42 am
Ans for 32 is B.
cuz the magnetic field lines have to be cut for a p.d to be induced.
How have the magnetic field lines been cut since we are not moving the magnet?
Post by: nid404 on June 09, 2009, 06:08:39 am
Post by: annie_angel on June 09, 2009, 06:10:34 am
Post by: QuickSilver on June 09, 2009, 06:12:17 am
wats da usual grade threshold for A in physics paper 1??34 to 37 /40
Post by: annie_angel on June 09, 2009, 06:16:05 am
Post by: IGSTUDENT on June 09, 2009, 06:53:10 am
the bar is inside the solenoid..it was moved into the solenoid,causing the field line to be cut. the rest r not correct anyways. For A the magnet is a part of the whole connection(absolutely wrong) for C the magnet is outside the solenoid and being rotated(if it were inside then a pd would be induced as rotating outside does not cut the field line and for D the magnet is being taken away from the solenoid it needs to be taken into it so that field lines can be cutThanks!!!!
Post by: examsaresoon on June 09, 2009, 08:20:56 am
Post by: QuickSilver on June 09, 2009, 09:06:08 am
Can some one please help me out? In Oct/Nov 2007...there are a two questions i don't understand. Question 7 and 21. Help would be appreciate it!
Question 7.
The mass of the drum is 200 WHEN EMPTY, when full of the spirit, it is 1000kg, so this means that the mass of the spirit is....800kg's
And since density=Mass/Volume, so, Density=800kg/1cm3 which is equal to 800Kg/Cm3
Answer: C
Question 21.
The line should represent the amplitude, because the aomplitude is the line that is in the middle and ANY WAVE THAT RESTS WILL BE ALINE WITH THE AMPLITUDE, Answer:B
Hope I Helped, Dont Forget +REP ;)
Best Wishes
Post by: examsaresoon on June 09, 2009, 09:10:53 am
Post by: QuickSilver on June 09, 2009, 09:12:11 am
Thanks! + rep !!Sure, Thanks :)
Post by: 247sports on June 09, 2009, 10:38:37 am
usually in phy ppr 1 they giv u pics n ask u which 1 has the gr8tst thermal capacity
how do we koe which one is the answer ???
any help is appreciatd
Thanks
Post by: sweetsh on June 09, 2009, 10:40:46 am
Post by: 247sports on June 09, 2009, 10:42:18 am
Post by: sweetsh on June 09, 2009, 10:49:53 am
q16..I think it's A because it has the least temprature rise..As they didnt mention anything about masses..
for q8 I think it's A only one model will fall over
Post by: 247sports on June 09, 2009, 11:01:34 am
;D
+rep 4 u
Post by: sweetsh on June 09, 2009, 11:03:41 am
Post by: Hope on June 09, 2009, 11:08:11 am
Post by: sweetsh on June 09, 2009, 11:10:28 am
Post by: Hope on June 09, 2009, 11:20:20 am
Post by: cockyxrocker on June 09, 2009, 11:32:39 am
Thanks
Post by: winnie101 on June 09, 2009, 11:35:11 am
can anyone tell me the reasoning behind q31, o/n 2006 pap1. the is supposed 2be D
thx
Post by: winnie101 on June 09, 2009, 12:04:57 pm
thx
Post by: sweetie on June 09, 2009, 12:05:40 pm
ineed help in p1 oct06 que.33
i think it should b B but mark scheme says its A????
Post by: winnie101 on June 09, 2009, 12:14:35 pm
Post by: 7ooD on June 09, 2009, 02:22:41 pm
Post by: theigstudent on June 09, 2009, 05:45:37 pm
The half-life of a radioactive substance is 5 hours. A sample is tested and found to contain 0.48 g
of the substance.
How much of the substance was present in the sample 20 hours before the sample was tested?
A 0.03 g
B 0.12 g
C 1.92 g
D 7.68 g
wats the answer 4 this n how do u find it
Post by: Ghost Of Highbury on June 09, 2009, 05:47:27 pm
0.48 * 4 = 1.92 g
Post by: Tanya on June 09, 2009, 05:48:20 pm
Post by: theigstudent on June 09, 2009, 05:49:27 pm
20/5 = 4
0.48 * 4 = 1.92 g
sorry but in the ms the ans was D
so plz help
Post by: Ghost Of Highbury on June 09, 2009, 05:49:54 pm
ill try again
which paper is this????
Post by: basoom16 on June 09, 2009, 05:50:29 pm
Post by: basoom16 on June 09, 2009, 05:51:50 pm
Post by: Ghost Of Highbury on June 09, 2009, 05:52:58 pm
5 hours before it was = 0.48 * 2 = 0.96
10 hours before it was = 0.96 * 2 = 1.92
15 hours before it was = 1.92 * 2 = 3.94
and 20hours it was = 3.84 * 2 = 7.68 = D
Post by: basoom16 on June 09, 2009, 05:54:14 pm
Post by: theigstudent on June 09, 2009, 05:58:26 pm
Thanks a million
:)
n does ny1 know abt the gradient
Post by: Ghost Of Highbury on June 09, 2009, 06:01:16 pm
question no???
Post by: Clem on June 09, 2009, 06:05:04 pm
Check this out : When we put our hands above a fire most of the heat gets tranferred by convection, while the energy from solar pannels mostly comes from radiation, so how come?
Post by: Ghost Of Highbury on June 09, 2009, 06:07:13 pm
Post by: godfather93 on June 09, 2009, 06:08:14 pm
@adi - wow! ur rep is shooting up everyday. let me help u! +rep! :D
Post by: Clem on June 09, 2009, 06:09:29 pm
Post by: Ghost Of Highbury on June 09, 2009, 06:09:50 pm
long time no c...
how are you??
Post by: theigstudent on June 09, 2009, 06:10:20 pm
4 the answer
i mean wat is the threshold 4 the pap1
Post by: godfather93 on June 09, 2009, 06:13:43 pm
hey hii godfather
long time no c...
how are you??
hey adi! the problem was with my internet, the whole connection was down for 2 days. I'm doing fine (not gonna be soon).
Hows things over there?
Post by: Ghost Of Highbury on June 09, 2009, 06:14:33 pm
school started
best of luck for ur exam :)
Post by: godfather93 on June 09, 2009, 06:15:47 pm
its awesome out here
school started
best of luck for ur exam :)
thanks for the wishes! when exactly did u have ur summer vacation and for the students doing igcse, don't they get vacation?
Post by: Ghost Of Highbury on June 09, 2009, 06:17:03 pm
whereas the heat transferred from the sun to the solar panels is majorly in the form of radiation ... because in outer space there r negligible air molecules to transfer the heat...
Post by: Ghost Of Highbury on June 09, 2009, 06:17:35 pm
our vaccations were till 8th of june../.
Post by: godfather93 on June 09, 2009, 06:19:22 pm
v r the first batch in our school..
our vaccations were till 8th of june../.
888 posts! u have vacation in batches? never heard of that before. y does school start so early there?
Post by: theigstudent on June 09, 2009, 06:20:17 pm
gud no ;)
Post by: Ghost Of Highbury on June 09, 2009, 06:20:48 pm
Post by: Ghost Of Highbury on June 09, 2009, 06:21:05 pm
congratzz
Post by: theigstudent on June 09, 2009, 06:23:06 pm
realli happy :) :D
Post by: godfather93 on June 09, 2009, 06:25:27 pm
Post by: theigstudent on June 09, 2009, 06:26:15 pm
n
best of luck every1 4 the exams
Post by: Petrol on June 09, 2009, 06:38:37 pm
other than pastpapers what i can do?
Learn all the formulas?
What are the main things i should kno before..?
Post by: nid404 on June 09, 2009, 06:42:35 pm
can sum1 explain thermal heat capacity?
other than pastpapers what i can do?
Learn all the formulas?
What are the main things i should kno before..?
thermal capacity - the amount of heat energy needed to raise the mass of a body by 1oC.
learning important formulae may help..
Post by: goin4dakill on June 09, 2009, 06:47:41 pm
Whats the formula for heat capacity though?
Post by: godfather93 on June 09, 2009, 06:52:49 pm
Oh, I wanted to ask that..as well.
Whats the formula for heat capacity though?
energy transferred = mass x specific heat capacity
Post by: Ghost Of Highbury on June 09, 2009, 06:56:21 pm
i just want the diagram for the image for the plane mirror
thanks
Post by: me...myself...n...i on June 09, 2009, 07:00:50 pm
dnt get it....
answer is C ....but how??
Post by: nid404 on June 09, 2009, 07:01:46 pm
november 2007 paper 3 Q 6 a
i just want the diagram for the image for the plane mirror
thanks
Image of O will be behind the mirror..sorry no time to draw it
Post by: Ghost Of Highbury on June 09, 2009, 07:02:26 pm
thanks
Post by: Ghost Of Highbury on June 09, 2009, 07:04:40 pm
volume = 60 cm ^3 as shown
therefore desity = mass/volume = 40/60 g/cm^3
Post by: Ghost Of Highbury on June 09, 2009, 07:06:05 pm
volume as shown = 60 cm ^3
therefore density = mass/volume => 40/60 g/cm^3
Post by: me...myself...n...i on June 09, 2009, 07:06:37 pm
Post by: me...myself...n...i on June 09, 2009, 07:07:22 pm
Post by: Ghost Of Highbury on June 09, 2009, 07:07:55 pm
yh but the options are like 40 + 60???i first thought that its +
but later assumed its "/"
i think the markscheme is wrong
actually all the options are incorrect
which paper is this???
Post by: me...myself...n...i on June 09, 2009, 07:09:27 pm
Post by: nid404 on June 09, 2009, 07:10:20 pm
Post by: me...myself...n...i on June 09, 2009, 07:17:48 pm
but yup it looks scanned so yh...n besides the qn wud be wrong.....
didnt think bout tht....Thanks for tht :)
Post by: astarmathsandphysics on June 09, 2009, 07:43:18 pm
Post by: 247sports on June 09, 2009, 07:44:22 pm
do well *just twoo mre dayz...cn u belive it dat v gav xamz for one whole mnth :o i cant*
anewho break a leg ppl
Post by: Ghost Of Highbury on June 09, 2009, 07:45:12 pm
astar plzz helpp
Post by: astarmathsandphysics on June 09, 2009, 07:50:06 pm
C
Post by: Ghost Of Highbury on June 09, 2009, 07:51:25 pm
The reistance of one lamp is greater than the resuistance of 2 lamps in paralell - twice as great so the current will decreasei though soo
C
but the rest told me that it has to be A
yess...i was correct
thanks astar
Post by: shan2391 on June 09, 2009, 07:52:47 pm
Post by: Ghost Of Highbury on June 09, 2009, 07:54:10 pm
30 ; 15
notice the parallel lines
Post by: goin4dakill on June 09, 2009, 07:57:43 pm
Okay for graphs- or screens for AC and DC.
Hmm, how do we explain this.. But i guess an AC screen, would be like 'hills' one on top and one on the bottom? right?? Ok i know that..
but for DC? I know they 'hills' are all on the top, but are they next to eachother or are gaps left in the middle??? HELP
and exuse my amateur physics <3 haha
Post by: astarmathsandphysics on June 09, 2009, 08:03:29 pm
If it is from a rectifier it is like hills next to each other
Post by: goin4dakill on June 09, 2009, 08:05:07 pm
If it from a battery it is a straight horizontal line
If it is from a rectifier it is like hills next to each other
Thanks Astar! So no gaps?? Why did my teacher tell me that -.-
Post by: samin6n on June 09, 2009, 08:08:15 pm
Post by: samin6n on June 09, 2009, 08:10:34 pm
Post by: bball92 on June 09, 2009, 08:15:26 pm
however 9 is b because its the most stable arrangement. the clamp is steady and the jar or w/e it is is closest to the surface so incase the clamp opens the jar wouldnt smash or anything.
Post by: samin6n on June 09, 2009, 08:19:39 pm
Post by: bball92 on June 09, 2009, 08:21:06 pm
Post by: lana on June 09, 2009, 09:44:13 pm
1- the mass of a full bottle of cooking oil is 1.3 kg when exactly half the oil is used the mass of the bottle and the remaining oil is 0.9 kg what is the mass of the bottle ? now i know it's ''B'' but how ??
2- the half life of a radioactive substance is 5 hours a sample is tested and found to contain 0.48 g of the substance how much of the substance was present in the sample 20 hours before the sample was tested ?? i also know its ''D'' but again how ??
thanks and +rep for anyone who answers =]
Post by: hmh on June 09, 2009, 09:49:15 pm
hi ... !! ok i have two questions it's from past papers June and November 03 :
1- the mass of a full bottle of cooking oil is 1.3 kg when exactly half the oil is used the mass of the bottle and the remaining oil is 0.9 kg what is the mass of the bottle ? now i know it's ''B'' but how ??
2- the half life of a radioactive substance is 5 hours a sample is tested and found to contain 0.48 g of the substance how much of the substance was present in the sample 20 hours before the sample was tested ?? i also know its ''D'' but again how ??
thanks and +rep for anyone who answers =]
OK so 1 is B i dnt knw the value 1.3- 0.9 = 0.4 * 2 = 0.8 ... we got 1.3 - 0.8 = 0.5 kg as 0.5 kg mass of bottle.
2 .. again didnt look at the paper.. but guessesing tht answer shd be 7.68g... as 4 half lives reversed as of 5 hrs 1 time.. so 0.48*2*2*2*2 = 7.68.
Post by: MR.BooMBastiC on June 09, 2009, 09:51:42 pm
the second is 7.68
Post by: lana on June 09, 2009, 09:53:44 pm
Post by: hmh on June 09, 2009, 09:54:49 pm
exactly 1 - is 0.5 and 2- is 7.68 i'm sorry your work is not right but + rep for u anyway thanks
i dnt want +reps lol.. i want to help. srry i misunderstood them.. now i jst corrected... u can check bak :)
Post by: MR.BooMBastiC on June 09, 2009, 09:55:18 pm
i wrote da value wring by mistake!
i hav corrected it
best of luck mate!!
Post by: lana on June 09, 2009, 09:56:52 pm
+ rep 4 u =p
and best of luck for u 2 !!! =]
Post by: Bani on June 09, 2009, 09:57:18 pm
hi ... !! ok i have two questions it's from past papers June and November 03 :
1- the mass of a full bottle of cooking oil is 1.3 kg when exactly half the oil is used the mass of the bottle and the remaining oil is 0.9 kg what is the mass of the bottle ? now i know it's ''B'' but how ??
2- the half life of a radioactive substance is 5 hours a sample is tested and found to contain 0.48 g of the substance how much of the substance was present in the sample 20 hours before the sample was tested ?? i also know its ''D'' but again how ??
thanks and +rep for anyone who answers =]
For no.1 : first find the mass of the half of oil( 1.3-0.9=0.4), then u know that other half is 0.4 too. So, subtract the whole mass of oil (0.4*2) from the mass of bottle and oil (1.3) to get 0.5kg
For no. 2: Half life(time for value to half) is 5 hours, and there are 4 5s in 20(meaning you'll have to multiply 0.48 by 2 4 times to get the value 20 hours before decay
so, finally, you'll get 7.68g
I hope this helped
OK so 1 is B i dnt knw the value because i didnt look at exam but shud be 0.25kg becuz.. 1.3/2 = 0.65 half left... but we got 0.9 kg as mass so 0.9-0.65 = 0.25 kg mass of bottle.
2 .. again didnt look at the paper.. but guessesing tht answer shd be 1.92g... as 4 half lives reversed as of 5 hrs 1 time.. so 0.48*4 = 1.92.
Post by: hmh on June 09, 2009, 09:58:38 pm
hi ... !! ok i have two questions it's from past papers June and November 03 :
1- the mass of a full bottle of cooking oil is 1.3 kg when exactly half the oil is used the mass of the bottle and the remaining oil is 0.9 kg what is the mass of the bottle ? now i know it's ''B'' but how ??
2- the half life of a radioactive substance is 5 hours a sample is tested and found to contain 0.48 g of the substance how much of the substance was present in the sample 20 hours before the sample was tested ?? i also know its ''D'' but again how ??
thanks and +rep for anyone who answers =]
For no.1 : first find the mass of the half of oil( 1.3-0.9=0.4), then u know that other half is 0.4 too. So, subtract the whole mass of oil (0.4*2) from the mass of bottle and oil (1.3) to get 0.5kg
For no. 2: Half life(time for value to half) is 5 hours, and there are 4 5s in 20(meaning you'll have to multiply 0.48 by 2 4 times to get the value 20 hours before decay
so, finally, you'll get 7.68g
I hope this helped
OK so 1 is B i dnt knw the value because i didnt look at exam but shud be 0.25kg becuz.. 1.3/2 = 0.65 half left... but we got 0.9 kg as mass so 0.9-0.65 = 0.25 kg mass of bottle.
2 .. again didnt look at the paper.. but guessesing tht answer shd be 1.92g... as 4 half lives reversed as of 5 hrs 1 time.. so 0.48*4 = 1.92.
yea lol.. i corrected myself :P thanks anyway
Post by: MR.BooMBastiC on June 09, 2009, 10:02:48 pm
i will be more than happy to help u...
Post by: lana on June 09, 2009, 10:05:29 pm
Post by: Petrol on June 09, 2009, 10:11:40 pm
Post by: MR.BooMBastiC on June 09, 2009, 10:12:12 pm
it was nice talking to u!! ;) :)
Post by: lana on June 09, 2009, 10:15:52 pm
and MR.BooMBastiC ! it was great talking to u 2 =]
Post by: hmh on June 09, 2009, 10:16:22 pm
heyy november 2003 question 3 it doesnt make sense are u sure the mark scheme is correct i think it should be D but it says A :s
It should be A.. as it asks for the most/ greatest time to pass throught poles.. so tht is 1 and 2 wen the car is slowly accelerating to high speed.
Post by: astarmathsandphysics on June 09, 2009, 10:16:48 pm
heyy november 2003 question 3 it doesnt make sense are u sure the mark scheme is correct i think it should be D but it says A :s
it is a
it takes longest when it is travelling slowest ie between the first 2 poles
Post by: MR.BooMBastiC on June 09, 2009, 10:26:04 pm
Post by: nid404 on June 10, 2009, 07:33:27 am
U are so unkind u swine...
People need to get into university, and i am helping people with it!!!
if ur so confident of ur answers, keep them to urslf, or contribute like me!
By the way crudity is not tolerated..
u have been reported..the moderator will decide ur fate
Post by: esso on June 10, 2009, 07:38:39 am
thats wat he deserves......kicked out of this forum....
i saw this answers bt they r wrong...most of dm,,,,,
u know i just came from the exam....its easy .... does not require cheating at all....
nd with this cheated answers u ll get less marks then u coud have got....
Post by: nid404 on June 10, 2009, 07:40:43 am
thats wat he deserves......kicked out of this forum....
i saw this answers bt they r wrong...most of dm,,,,,
u know i just came from the exam....its easy .... does not require cheating at all....
nd with this cheated answers u ll get less marks then u coud have got....
Thanks for the support :)
Post by: Friends on June 10, 2009, 07:43:22 am
And plzzz moderater dont ban me for this:
ANSWERS GO F**K URSELF.
Post by: esso on June 10, 2009, 07:50:15 am
Post by: nid404 on June 10, 2009, 07:51:34 am
+rep for u all for keeping the forum clean.....
for u too...but the forum is not clean cuz the site is still in many threads and circulating. I hope the moderator reviews this and takes action
Post by: Friends on June 10, 2009, 07:53:26 am
+rep for u all for keeping the forum clean.....
for u too...but the forum is not clean cuz the site is still in many threads and circulating. I hope the moderator reviews this and takes action
But most of the MODS AND ADMINS are not ONLINE at this time.
Yesterday I reported ROCKSTAR but IT took nearly an hour or more to ban him.
Post by: Friends on June 10, 2009, 08:05:03 am
Who the *censored* do you think u are, b*tch.
(Dont ban me for this)
YOUR MOTHER
Post by: nid404 on June 10, 2009, 08:06:21 am
Who the *censored* do you think u are, b*tch.
(Dont ban me for this)
YOUR MOTHER
LOOOOOOOOOL :D
Post by: Friends on June 10, 2009, 08:08:25 am
Post by: nid404 on June 10, 2009, 08:12:09 am
Post by: sweetie on June 10, 2009, 08:37:23 am
do heavy objects hav more mass dan lighter objects???????????????
Post by: nid404 on June 10, 2009, 08:44:19 am
Post by: esso on June 10, 2009, 09:33:55 am
Post by: esso on June 10, 2009, 09:34:40 am
help
do heavy objects hav more mass dan lighter objects???????????????
24 hrs my friend ,,,
Post by: leebux101 on June 10, 2009, 03:13:15 pm
helphey thts a question for the exam!!! wait for 24 hrs!!!!
do heavy objects hav more mass dan lighter objects???????????????
Post by: astarmathsandphysics on June 10, 2009, 08:51:25 pm
Post by: sean1234 on December 18, 2009, 04:02:54 pm
anyone has old pass papers for physics paper 3 n 1??
from 1993-2002
if so can some one send me on teenangel_MK@hotmail.com
thankyou
Send to me please as well thanks
Post by: zara on December 19, 2009, 01:48:16 pm
Send to me please as well thanksi think its there on freeexampapers now
Post by: zara on December 19, 2009, 01:49:51 pm
http://www.freeexampapers.com/Dndex.php?d=SUdDU0UvUGh5c2ljcy9DSUU=
chk in here.
Post by: sean1234 on December 20, 2009, 08:38:13 am
Post by: holtadit on December 27, 2009, 11:38:05 am
(a) Calculate the deceleration of the cyclist.
deceleration = ..................................
(b) Calculate the distance travelled by the cyclist in this time.
distance = ..................................
How would u do the (b) part ? The examiners report says that it should be average speed multiplied time... but how do u get the average speed ? Please show your workings !
Post by: astarmathsandphysics on December 27, 2009, 01:40:54 pm
Post by: saleemsamer on December 27, 2009, 03:05:09 pm
Average speed is (u+v)/2=(2.5+10)/2=6.25it is 1.0 not 10
Post by: astarmathsandphysics on December 27, 2009, 03:36:45 pm
\skldnb c1juk
sHOOT ME AGAIN!!!!!!!!!!!!
Post by: holtadit on January 01, 2010, 09:44:02 am
Why do you haave to subtract 2.1g from 16.3 grams ?
The Examiners Report says that many student didnt understand the significance of the 2.1g melted in the 2 minutes.
So what is the significance ?
Post by: astarmathsandphysics on January 01, 2010, 10:33:02 am
Post by: holtadit on January 01, 2010, 10:40:38 am
using Q=ml do (2.1-1.3)/4min * 60
If the 2.1 grams melted without the heater in the next 2 minutes why is a total of 4 minutes being used in Q=ml ??
Post by: holtadit on January 01, 2010, 11:31:55 am
Post by: astarmathsandphysics on January 01, 2010, 02:09:16 pm
Post by: astarmathsandphysics on January 01, 2010, 02:14:21 pm