Post by: mz on May 15, 2010, 01:01:25 pm
Post by: [Spy] on May 15, 2010, 01:12:15 pm
what a question -.-
Post by: mz on May 15, 2010, 01:15:54 pm
yes please me tooo
what a question -.-
exactly.....why have they not taken atmospheric pressure into consideration??? this is silly...
Post by: halosh92 on May 15, 2010, 01:19:55 pm
Post by: halosh92 on May 15, 2010, 01:22:53 pm
therefore
pressure of water + pressure of oil = total pressure
phg+phg=total pressure
1000*(2000-x)*9.8 + 830*x*9.8=17.5*10^6
just arrange the formulas
it will be around 1260 whis nearest to the answer D
Post by: halosh92 on May 15, 2010, 01:25:20 pm
june 2006 p1
Q33
Q24
Q25
Q28
Post by: [Spy] on May 15, 2010, 01:29:04 pm
Post by: nid404 on May 15, 2010, 01:30:22 pm
why is total pressure 17.5* 10^6?
it's mentioned in the question
Post by: halosh92 on May 15, 2010, 01:30:49 pm
why is total pressure 17.5* 10^6?
because its MPa mega Pascale
u have to change to pascale so *10^6
Post by: halosh92 on May 15, 2010, 01:32:31 pm
Q12
Post by: nid404 on May 15, 2010, 01:45:36 pm
i have these doubts too
june 2006 p1
Q33
Q24
Q25
Q28
Q24)intensity=ka2. using numericals would be helpful here
consider a=2 and k=1 I=4
if I has to be 8 a will be
And half the frequency means twice the wavelength. Hence B
Q25) calculate the wavelength first.
w= v/f = 340/500=0.68m
0.68m= 2
0.17= ?
0.17X 2
--------------------
0.68
=1/2
So B
Post by: nid404 on May 15, 2010, 01:50:31 pm
a=distance between the slit
x=fringe spacing
D=distance from screen
x is initially =4mm
now the slit spacing is halved so 1/2 a
D is doubled and is now 2D
wavelength is constant
earlier x= (
now x= (
x is 4 times greater
so x is 4X4=16mm
Post by: nid404 on May 15, 2010, 01:53:52 pm
V=12V
It is same in both parallel wires.
it splits depending on the ratio of the resistor. Greater the resistance, more the voltage across it.
in first wire
across 500= 500/1500 X 12= 4V [X]
in the second wire
across 2000=2000/3000 X12=8V [Y[
p.d between the 2 points X and Y = 4V
Post by: [Spy] on May 15, 2010, 01:54:10 pm
i have these doubts too
june 2006 p1
Q33
Q24
Q25
Q28
Q24) since intensity is directly proportional to amplitude SQUARED then the sqaure root of intensity is proportional to amplitude, and therfore if the intensity is double then the intensity has to increase by a square root of 2, and the frequency is halfed therfore each wave takes double the number of squares, which means its B :D
Q25) the wavelength is equal to 340/500= 0.68
and it ask for the phase difference between two points on the SAME WAVE, and since the wavelength is 0.68, and the two points are 0.17 apart then its 0.17/0.68, then you have to multiply it by 360, this gives 90 degrees, and since pie is equal to 180 then the answer is B pie/2
Q28) we know that wavelength/distance between slits is = distance between two fringes/distance to screen
and therefore we want to know the relation between the distance between two fringes and the slit spacing therefore we have to re arrange the equation so that they are on different sides of the equation, but the equation already satisfies that and therefore, when the distance between the slits halfs the distance between 2 fringes has to double as they are inversely proportional because one is numerator and the other is denominator, and therefore that gives us a fringe spacing of 8, but then the distance to screen doubles, arranging the equation to make the distance to the screen on the left hand side we see that is directly proportional to the fringe spacing and therfore as it doubles the fringe spacing has to double to giving us 16mm
Post by: halosh92 on May 15, 2010, 02:02:44 pm
may june 2007
Q7
Q10
thx ^^ ;D ;D ;D ;D
Post by: [Spy] on May 15, 2010, 02:14:15 pm
thankyouuuu so much both of u.
may june 2007
Q7
Q10
thx ^^ ;D ;D ;D ;D
Q7) as vector V has to equal vector U+X then final velocity V= Initial velocity U + X
if you look at the equation of motion v=u+at, then you'll see that simply, x is at
:)
Post by: [Spy] on May 15, 2010, 02:21:55 pm
and a=(v-u)/t
then F= m(v-u) all /t
m(v-u) is equal to the change in momentum there fore F=momentum/time
and since its asking for force BETWEEN time t1 and t2 you have to include a time difference, and therefore answer is B
:)
Post by: halosh92 on May 15, 2010, 02:24:21 pm
Post by: cashem'up on May 15, 2010, 02:55:03 pm
Which formula could be correct for the speed v of ocean waves in terms of the density ? of seawater,
the acceleration of free fall g, the depth h of the ocean and the wavelength ??
A : root g lambda
B root g/h
C root rowgh
D root g/row
Post by: [Spy] on May 15, 2010, 03:07:18 pm
thankyouuuuuuuuuuu ;D
no problemm :D
Post by: nid404 on May 15, 2010, 03:15:39 pm
came across a question in june 2002 q3
Which formula could be correct for the speed v of ocean waves in terms of the density ? of seawater,
the acceleration of free fall g, the depth h of the ocean and the wavelength ??
A : root g?
B root g/h
C root ?gh
D root g/?
what's the ?
Post by: [Spy] on May 15, 2010, 03:23:04 pm
what's the ?
row, density sign
Post by: halosh92 on May 15, 2010, 03:34:59 pm
Q12
Post by: princess12 on May 15, 2010, 03:35:47 pm
tell me yes or no
Post by: nid404 on May 15, 2010, 03:36:16 pm
Post by: nid404 on May 15, 2010, 03:36:50 pm
Post by: princess12 on May 15, 2010, 03:37:29 pm
Post by: nid404 on May 15, 2010, 03:38:50 pm
what is ur name
huh? ::)
Post by: [Spy] on May 15, 2010, 03:42:25 pm
2009 nov
Q12
for variant 1...
i personally find this question difficult and time consuming, so here's an easier way ;)
R1 and R2 HAVE to be equal because they are both vertical and they have the same masses connected to them...when we come to the T's, they cant be equal because you have changed the angles at which they are positioned and therefore the answer which meets those requirments is B
:P
examiners actually said that students will find an easier way of doing questions rather than deriving long stepped equations such as teachers (A)
Post by: Saladin on May 15, 2010, 03:42:35 pm
huh? ::)
Her name is Queen Nandita Ramakrishna the third.
Post by: nid404 on May 15, 2010, 03:43:57 pm
Her name is Queen Nandita Ramakrishna the third.
Thanks for answering that dude. + rep :P
Post by: ifraha18 on May 15, 2010, 03:45:56 pm
Post by: halosh92 on May 15, 2010, 03:46:12 pm
for variant 1...
i personally find this question difficult and time consuming, so here's an easier way ;)
R1 and R2 HAVE to be equal because they are both vertical and they have the same masses connected to them...when we come to the T's, they cant be equal because you have changed the angles at which they are positioned and therefore the answer which meets those requirments is B
:P
examiners actually said that students will find an easier way of doing questions rather than deriving long stepped equations such as teachers (A)
thankyou :D
but i need variant 2 ;D :D
Post by: Saladin on May 15, 2010, 03:50:02 pm
Thanks for answering that dude. + rep :P
is that really ur name?
Post by: AN10 on May 15, 2010, 03:50:51 pm
Sound from a small loudspeaker L reaches a point P by two paths which differ in length by 1.2m. When the frequency of the sound is gradually increased, the resultant intensity at P goes through a series of maxima and minima. A maximum occurs when the frequency is 1000 Hz and the next maximum occurs at 1200 Hz. What is the speed of sound in the medium between L and P?
A 200
B 240
C 480
D 1200
E 1400
Post by: [Spy] on May 15, 2010, 03:52:10 pm
q18 nov 2005.?
since the pressures are equal then P1=P2
P1 for X is equal to 800*9.8*h1
P2 For Y is equal to 1200*9.8*h2
if you make them equal to each other (since pressure is equal, cause thats what they are asking for)
then....7840h1=11760h2
re-arrange to give h2/h1=7840/11760, that ratio gives 2/3
then you check which one of the choices gives a ratio of 2/3 when you divide the length of Y OVER X because we used h2/h1
:D
Post by: nid404 on May 15, 2010, 03:54:03 pm
came across a question in june 2002 q3
Which formula could be correct for the speed v of ocean waves in terms of the density ? of seawater,
the acceleration of free fall g, the depth h of the ocean and the wavelength ??
A : root g lambda
B root g/h
C root rowgh
D root g/row
In this particular question check the units on each side.
unit for v= m/s
Post by: ifraha18 on May 15, 2010, 03:54:42 pm
Post by: nid404 on May 15, 2010, 03:58:25 pm
is that really ur name?
hasna tha? ::)
Post by: [Spy] on May 15, 2010, 03:59:44 pm
Thanks man!!! ND NOV 2005 Q7
CHECK FOR HOMOGENITY!!!!! it asks for acceleration there fore the units have to be m/s^-2 then i think B and D cancel out and your left with A and C,, but you need time difference obviously so its C :)
Post by: [Spy] on May 15, 2010, 04:00:56 pm
thankyou :D
but i need variant 2 ;D :D
its not opening on free exam papers, please post it here :)
Post by: halosh92 on May 15, 2010, 04:02:05 pm
CHECK FOR HOMOGENITY!!!!! it asks for acceleration there fore the units have to be m/s^-2 then i think B and D cancel out and your left with A and C,, but you need time difference obviously so its C :)
the answer is D though
Post by: halosh92 on May 15, 2010, 04:04:45 pm
Q20
Post by: [Spy] on May 15, 2010, 04:06:34 pm
the answer is D though
yeah im sorry its D because at C, homogenity does not apply because you have S^2-S^2
:)
Post by: [Spy] on May 15, 2010, 04:14:30 pm
june 2007
Q20
Answer is B
at X it has to be tension because its opposite directions, and at Y it also has to be tension because if you look at the far end of the pillar horizantally, at the curved part on the right, if you trace the force exerted by F, you see that it applies a pulling force on Y therefore its tension, i would also assume Z is tension, BUT here's paper 1 tricks, you dont have Z with tension and your sure X and Y are tension there fore it has to be B
:D
Post by: halosh92 on May 15, 2010, 04:22:57 pm
Answer is B
at X it has to be tension because its opposite directions, and at Y it also has to be tension because if you look at the far end of the pillar horizantally, at the curved part on the right, if you trace the force exerted by F, you see that it applies a pulling force on Y therefore its tension, i would also assume Z is tension, BUT here's paper 1 tricks, you dont have Z with tension and your sure X and Y are tension there fore it has to be B
:D
am rili sorry i just dont get it what u mean by:
at X it has to be tension because its opposite directions ???
sorry for the trouble :(
Post by: [Spy] on May 15, 2010, 04:27:09 pm
am rili sorry i just dont get it what u mean by:
at X it has to be tension because its opposite directions ???
sorry for the trouble :(
since the force W is pushing downwards, therefore X has to be going upwards just pulley for instance if you visualize it, understand?
and no its okay dont worry, what am i here for :)
Post by: halosh92 on May 15, 2010, 04:31:29 pm
since the force W is pushing downwards, therefore X has to be going upwards just pulley for instance if you visualize it, understand?
and no its okay dont worry, what am i here for :)
thankyou 8)
ok same paper Q23
Post by: [Spy] on May 15, 2010, 04:40:10 pm
thankyou 8)
ok same paper Q23
at Q, displacement can not be always zero as it is not a stationary wave, therefore we eliminate B, at R, its max. displacement and therefore it stopped so that it will then go back upwards, and hence we eliminate C now
as For point P, just like R its coming to rest, and therefore it should have MINIMUM speed and not MAXIMUM speed, . and therefore we eliminate A and the answer is D :)
the explanation for the answer, point S is going to start going downwards now and its going to have maximum acceleration initially then slow down as it arrives at the negative amplitude
hope this is clear :)
Post by: halosh92 on May 15, 2010, 04:47:24 pm
at Q, displacement can not be always zero as it is not a stationary wave, therefore we eliminate B, at R, its max. displacement and therefore it stopped so that it will then go back upwards, and hence we eliminate C now
as For point P, just like R its coming to rest, and therefore it should have MINIMUM speed and not MAXIMUM speed, . and therefore we eliminate A and the answer is D :)
the explanation for the answer, point S is going to start going downwards now and its going to have maximum acceleration initially then slow down as it arrives at the negative amplitude
hope this is clear :)
clear as crystal ;D
Post by: [Spy] on May 15, 2010, 04:58:01 pm
clear as crystal ;D
Great :D
Post by: [Spy] on May 15, 2010, 05:01:21 pm
answer should be D but its C :(
your supposed to add the uncertainties which means its 0.1+(0.01*3)= 0.13
anyone help??? cause this is not the answer
Post by: [Spy] on May 15, 2010, 05:17:58 pm
hey guys i rewrote the question can someone please solve it now............
check for homogenety
answer is square root of g/h
Post by: cashem'up on May 15, 2010, 05:19:53 pm
Post by: cashem'up on May 15, 2010, 05:20:41 pm
hasna tha? ::)haha :P lolz jk........
Post by: halosh92 on May 15, 2010, 05:35:35 pm
Q40
Post by: [Spy] on May 15, 2010, 06:09:21 pm
2007 may june
Q40
its supposed to be the ratio of charge/mass
and lithium has the least because charge for Lithium = 6 (protons + electrons)
and the mass= 7 therefore its 6/7
for the others if you the exact same thing you always get a larger value, and therefore its C
(ignore the negative in A)
:)
Post by: halosh92 on May 15, 2010, 06:37:50 pm
Q6
Q11
Post by: yinyang on May 15, 2010, 06:42:02 pm
june 2009
Q 14
Q 15
Post by: halosh92 on May 15, 2010, 06:46:49 pm
I have a question myself, nov05 question 5
answer should be D but its C :(
your supposed to add the uncertainties which means its 0.1+(0.01*3)= 0.13
anyone help??? cause this is not the answer
first,
find volume
V=L*B*H
so u find the %uncertainity of all three variables and add them
ok
this will come out A** 0.2%+0.5%+1%=1.7%
so 1.7% is the percentage uncertainity in volume
then u find the %uncertainity in mass
(0.1/25)*100=0.4%
so to find density
u use the formula D=M/V
means division
so u hv 2 add %uncertainity of volume n mass
1.7%+0.4%=2.1%
then he gave u the calculated value of density
so (2.1/100)*2.5(density value given)
answer comes out to be 0.0525
so 0.05 which C
Post by: ruby92 on May 15, 2010, 06:49:55 pm
3 18 22
??? ???
Post by: cashem'up on May 15, 2010, 06:51:42 pm
I have a question myself, nov05 question 5
answer should be D but its C :(
your supposed to add the uncertainties which means its 0.1+(0.01*3)= 0.13
anyone help??? cause this is not the answer
no i am pretty sure its C , whenever u r calculating uncertainties if its multi or division........u have to percentage uncertainties so
0.1/25 x 100 = 0.4%
0.01/5 x 100 = 0.2%
0.01/2 x 100= 0.5%
0.01/1 x 100 = 1%
now u add these so u get 2.1%......however we want in decimal
so 2.1/100 x 2.5= 0.0525
hope it helped
;D ;D ;D
Post by: halosh92 on May 15, 2010, 06:53:39 pm
can someone please help me with m/j 2003
3 18 22
??? ???
Q3
use the cosine rule , the angle would be 60
so
resultant= sqrt [10^2+10^2-(2*10*10*cos60)]
=10
Post by: astarmathsandphysics on May 15, 2010, 06:56:10 pm
Not technically the right way to do it.
11. D elastic so separation speed = approach speed and momentum conserved o
only possible answer is d
Post by: halosh92 on May 15, 2010, 06:57:15 pm
can someone please help me with m/j 2003
3 18 22
??? ???
Q18
v^2=u^2+2as
0= 10^2 + 2 * -a* 10
(a is negative as its decelrating)
a=5m/s^2
same force means same acceleration so:
same equation we use, but instead of u we put 30 and instead of "a" we put 5
u will get 90m which is D
Post by: halosh92 on May 15, 2010, 07:01:35 pm
6 D V=IR to get R=8 then add the uncertainites 20%+5% =25% of 8 +-2
Not technically the right way to do it.
11. D elastic so separation speed = approach speed and momentum conserved o
only possible answer is d
thankyou but for Q11 could u explain in detail ..how to apply this theory? ???
Post by: halosh92 on May 15, 2010, 07:22:47 pm
june 2005 Q22
nov 2008 Q24
Post by: [Spy] on May 15, 2010, 07:50:10 pm
no i am pretty sure its C , whenever u r calculating uncertainties if its multi or division........u have to percentage uncertainties so
0.1/25 x 100 = 0.4%
0.01/5 x 100 = 0.2%
0.01/2 x 100= 0.5%
0.01/1 x 100 = 1%
now u add these so u get 2.1%......however we want in decimal
so 2.1/100 x 2.5= 0.0525
hope it helped
;D ;D ;D
oh so you have to reverse it at the end! yeah thats my mistake!
thanks :D
Post by: ruby92 on May 15, 2010, 07:52:00 pm
Q3
use the cosine rule , the angle would be 60
so
resultant= sqrt [10^2+10^2-(2*10*10*cos60)]
=10
why is the angle 60?
Post by: halosh92 on May 15, 2010, 08:00:18 pm
why is the angle 60?
becaus ei have to imagine the same line on the other side, which makes it parallel, parallel lines: their interior angle add up to 180
so 180-120=60
trignometry u will have to imagine a triangle and use the cosine formula there
Post by: ruby92 on May 15, 2010, 08:06:00 pm
becaus ei have to imagine the same line on the other side, which makes it parallel, parallel lines: their interior angle add up to 180
so 180-120=60
trignometry u will have to imagine a triangle and use the cosine formula there
thnkx alot :)
o/n 2003 24 31
Post by: halosh92 on May 15, 2010, 08:20:09 pm
thnkx alot :)
o/n 2003 24 31
np
ok Q24
just draw 6 lines imagine each as a node, count the spaces between the line they are 5 spaces
30/5 = 6cm
so 6 is one space , the distance form one line to the other (one node to the other) makes half a wavelength
which is 6cm
one full wavelength is thereofre 12cm so its D
Q31
first find total resistance :
(6*3)/(6+3)=2
2+2= 4 ohms
total R= 4 ohms
total V=12V
now find voltage for the parallel connections , treat the 6ohms and 3ohms as a single resistor so:
(6*3)/(6+3)=2
2* current = 2*3=6V
since its parallel , the 6ohms gets 6V so does the 3ohms
so
R=V/I
I=V/R
I=6/6= 1 A
got it?
Post by: astarmathsandphysics on May 15, 2010, 08:29:31 pm
Post by: ruby92 on May 15, 2010, 09:58:03 pm
31 (why not C) 21 20
Post by: halosh92 on May 15, 2010, 10:17:43 pm
M/j 2004 9 14 (why isnt it A)
31 (why not C) 21 20
Q14: its B because its in equiliberium which means the triangle arrows must be head to tail like in B
Q31: R=V/I
R=row L/A
since V , L ,row are same they cancel out so we can write it like this
1/I = 1/A (THIS IS FOR P)=1/A(THIS IS FOR Q)
FOR P:
A= pie r^2 thereofre
1/pie
FOR Q:
A=pie r^2 therefore
1/pie 4
we cancel out the pie this remains
P:Q
1:1/4
so P is 4 times bigger than Q so its D
20: D (brownian motion)
Post by: astarmathsandphysics on May 15, 2010, 10:34:00 pm
Post by: halosh92 on May 15, 2010, 10:46:06 pm
Post by: ruby92 on May 15, 2010, 10:52:58 pm
Q14: its B because its in equiliberium which means the triangle arrows must be head to tail like in Bthnkxxxx
Q31: R=V/I
R=row L/A
since V , L ,row are same they cancel out so we can write it like this
1/I = 1/A (THIS IS FOR P)=1/A(THIS IS FOR Q)
FOR P:
A= pie r^2 thereofre
1/pie
FOR Q:
A=pie r^2 therefore
1/pie 4
we cancel out the pie this remains
P:Q
1:1/4
so P is 4 times bigger than Q so its D
20: D (brownian motion)
any ideas on 21 and 9???
Post by: halosh92 on May 15, 2010, 10:57:03 pm
thnkxxxx
any ideas on 21 and 9???
we did 21 in clas...but question 9 no idea actually :S
Post by: ruby92 on May 15, 2010, 11:40:45 pm
could you explain it again please.
o/n 2004 15 37 8
Post by: neno on May 16, 2010, 01:37:21 am
#oct/nov 2009(12)-Q14,Q27
#may/june 2009-Q11
#oct/nov2008-Q24,Q37(for 37 y do v need to noe the emf or cell 2)
#may/june 2008-Q26,Q22,Q16,Q14
Post by: halosh92 on May 16, 2010, 07:31:10 am
Q3
Q4 plzzz someone help :( :( :(
Post by: halosh92 on May 16, 2010, 09:19:14 am
jun 2005
Q3
Q4 plzzz someone help :( :( :(
could someone solve this plzz!!!!!!!!!!
Post by: astarmathsandphysics on May 16, 2010, 10:00:46 am
15 KE=1/2mv^2 so if v increases by factor 4 KE increases by factor 4^2
37resistance of 3-6 loop is 1/R=1/6+1/3=1/2 so R=2
resistance of 2-2 loop is 1/R=1/2+1/2=1 so R=1
more resistance in first loop so more voltage across first loop
ratio of resistance in 1st loop 1is 1:2 and ratio of resistance in 2nd loop is 1:1 so I_1>I-2
8 C the distance is increasing but the car is slowing down
Post by: astarmathsandphysics on May 16, 2010, 10:04:53 am
Q3
Q4 plzzz someone help
3 speed is d/t=100/10=10m/s
1/2mv^2=1/2*80*10^2=4000J
4 error in 2.5=2% error in 40=0.25%
sum of errors=2.25%
40/2.5=16 +-2.25%=16+-0.36
I think they do this wroong
Post by: astarmathsandphysics on May 16, 2010, 10:33:56 am
14 conservation of momentum
o=-2*2+1v so v=4
1/2mv^2 for both
1/2*2*2^2 +1/2*1*4^2=4+8=12
27 mg=Eq so q/m=g/E and charge must be negative since the drop is attracted to the positive plate
Post by: astarmathsandphysics on May 16, 2010, 10:37:14 am
pressure depends on depth increasing with depth
S=Q and R>P since s and q are at same depth and R is deeper than P
Post by: ruby92 on May 16, 2010, 10:40:44 am
9
25(point p with zero displacement be stationary?)
Post by: astarmathsandphysics on May 16, 2010, 10:42:58 am
24 3 times the frequency cos 3 little waves in the space of 1 big wave and half the amplitude
37 the emf of cell 2 will be the voltage across XT so voltage per unit length=E_2/XT
Post by: astarmathsandphysics on May 16, 2010, 10:50:08 am
26 twice as far so 1/2^2 =1/4 the intensity
27 D the wavelength is 4 x distance to wall cos node to antinode is 1/4 wavelength
22 c not elastic cos is deforming
14 A take moments about top of ladder against wall
16 A moves in direction of the force distance s so W=Fs
A
Post by: astarmathsandphysics on May 16, 2010, 10:55:49 am
vertically s=1/2at^2
1.25=1/2*10*t^2 so t^2 =0.25 so t=0.5
horizontally distance=speed*time
10=speed*0.5 so speed=20
25 A move the wave right a bit and see how P and Q have moved
Post by: mz on May 16, 2010, 11:57:34 am
Post by: ruby92 on May 16, 2010, 12:05:50 pm
10 13 20 33
Post by: halosh92 on May 16, 2010, 12:17:40 pm
un 2005
Q3
Q4 plzzz someone help
3 speed is d/t=100/10=10m/s
1/2mv^2=1/2*80*10^2=4000J
4 error in 2.5=2% error in 40=0.25%
sum of errors=2.25%
40/2.5=16 +-2.25%=16+-0.36
I think they do this wroong
for Q4 i got the same answer as yours ..so the ms is wrong?
Post by: Phosu on May 16, 2010, 12:28:15 pm
--> --->
2 kg 4 kg
4 m s–1 1 m s–1
After the impact they move off together.
What is the total kinetic energy of the trolleys after the collision?
A1.3J B12J C18J D19J
Post by: mz on May 16, 2010, 01:13:33 pm
Post by: halosh92 on May 16, 2010, 04:02:10 pm
explain plz
Post by: Phosu on May 16, 2010, 04:09:59 pm
2009 june Q18
explain plz
this is wat i think
the formula for pressure is pa=hdg
since the pressure here is increasing, cuz heat is being applied to gas, ke increase, causing the height of the mercury to increase
A is rong since its not the correct formula
B is rong since it would give the height before the gas was heated
C is rong cuz it shows pressure decreasing, but we want the pressure to increase
D is the only correct option.
Post by: [Spy] on May 16, 2010, 04:11:23 pm
2009 june Q18
explain plz
since pressure is = row*g*h
and the height increase is h then the pressure increase should be simply row*g*h
BUT, if you think about it, the left coloumn of liquid goes down by H and the right side colomn of liquid goes up by H, and therefore its row*g*2h which is D
:D
Post by: halosh92 on May 16, 2010, 04:14:15 pm
since pressure is = row*g*h
and the height increase is h then the pressure increase should be simply row*g*h
BUT, if you think about it, the left coloumn of liquid goes down by H and the right side colomn of liquid goes up by H, and therefore its row*g*2h which is D
:D
ahhh ure awesome thxxx ;D
Post by: [Spy] on May 16, 2010, 04:27:22 pm
ahhh ure awesome thxxx ;D
haha thanks :P
no problem :D
Post by: halosh92 on May 16, 2010, 04:48:47 pm
june 2009 p1 cie
Q10
Q13
explain plz
Post by: halosh92 on May 16, 2010, 04:55:47 pm
Post by: ruby92 on May 16, 2010, 05:21:47 pm
10 14 13 29
20 is maxima n*2?
21 why is it not B??
Post by: halosh92 on May 16, 2010, 05:24:12 pm
O/N 2009
10 14 13 29
20 is maxima n*2?
21 why is it not B??
which variant 1 or 2?
Post by: halosh92 on May 16, 2010, 05:28:59 pm
O/N 2009
10 14 13 29
20 is maxima n*2?
21 why is it not B??
post the paper plz
Post by: ruby92 on May 16, 2010, 05:34:18 pm
Post by: ruby92 on May 16, 2010, 05:37:04 pm
12 The diagram shows the masses and velocities of two trolleys about to collide.
--> --->
2 kg 4 kg
4 m s–1 1 m s–1
After the impact they move off together.
What is the total kinetic energy of the trolleys after the collision?
A1.3J B12J C18J D19J
is it B?
Post by: Phosu on May 16, 2010, 05:41:42 pm
june 2009 p1 cie
Q10
Q13
explain plz
10) momentum is conserved, take momentum for each side seperately
2m will have speed u
and m will have speed 2u, so that the product of both equations will give 2mu(same momentum)
ke
x= (2u)2 y=(u)2
so dividin both will give 4u/u which is 4/1
Post by: Phosu on May 16, 2010, 05:42:47 pm
is it B?
yah it is B, no worries i figured it out
Post by: ifraha18 on May 16, 2010, 05:43:45 pm
Post by: halosh92 on May 16, 2010, 05:57:54 pm
10) momentum is conserved, take momentum for each side seperately
2m will have speed u
and m will have speed 2u, so that the product of both equations will give 2mu(same momentum)
ke
x= (2u)2 y=(u)2
so dividin both will give 4u/u which is 4/1
they didnt mention whether its elastic or non elastic.
and one more question why do they exchange velocities????
Post by: [Spy] on May 16, 2010, 06:04:14 pm
june 2002 q21.???
P is density through out this question.
P=M/V
so V=M/P
the Final Volume = M/P + M/2P (densities stated in the question)
and this equals 3M/2P
the Final Density i.e P Final is equal to 2M/3M/2P (2M because they are combined together and they have both a mass of M and 3M/2P from the previous step i.e final volume)
therefore, P Final= 4/3 (2/(3/2))
hope its clear :D
Post by: ifraha18 on May 16, 2010, 06:07:39 pm
Post by: [Spy] on May 16, 2010, 06:08:53 pm
Post by: ifraha18 on May 16, 2010, 06:10:07 pm
Post by: hesho21 on May 16, 2010, 06:20:19 pm
Post by: mz on May 16, 2010, 06:29:15 pm
may/june 09 questions 15,19 and 29 please asap
please help
Post by: halosh92 on May 16, 2010, 06:30:40 pm
anyone?
Post by: ifraha18 on May 16, 2010, 06:36:11 pm
Post by: halosh92 on May 16, 2010, 06:43:54 pm
q 34 and 35 june 2002?????
q34) if u look carefully ull notice that its the same exact circuit therefore same brightness
q35) R3 and R1 gets both of them 2V that means both have the same resistance and that is an only option u can find in C
Post by: [Spy] on May 16, 2010, 06:52:20 pm
2009 nov Q14
anyone?
which variant?
Post by: halosh92 on May 16, 2010, 06:57:06 pm
please help
Q15: i have no idea
Q19: its a fact given in many books just learn it...i belive its somehting to do with the young modulus
Q29:
E=V/d also
V=W/q
W=work=energy= 1/2mv^2 (ke)
therefore
V=1/2mv^2 /e
so
E = 1/2mv^2 /e /x
just rearrange and make "x" as the subject ull get the answer in D
Post by: [Spy] on May 16, 2010, 06:57:40 pm
please help
the mass in X is going to half, and so does the height!
which means E potential= 0.5mg0.5h=mgh/4
therefore answer is B
19) its just a fact, plastic deforemation means it will not go back to its original shape, BUT the question says SUTAIN THE LARGEST PLASTIC DEFORMATION basically the object that can be bent the most, it cant be any brittles ones cause brittle means they shatter, and a fact - aluminium is more bendable than steel and so answer is A
29) i think this one of the questions that require time and a mood :P i have an easier way of these questions, since motion is involved in this question, then A and B cant be the right answer because they have mv and NOT mv^2 (which is kinetic energy i.e motion) and since we're looking at the motion of the electron then we have to include its charge obviously, therefore answer is D :)
Post by: ifraha18 on May 16, 2010, 06:59:36 pm
Post by: ruby92 on May 16, 2010, 07:02:16 pm
M/J 2009O/N 2009
10 13 20 33
10 14 13 29
20 is maxima n*2?
21 why is it not B??
Post by: Phosu on May 16, 2010, 07:13:55 pm
they didnt mention whether its elastic or non elastic.
and one more question why do they exchange velocities????
it doesn't matter, since momentum is conserved in both.
it may seem like they are exchangin velocites, but that is only to equate the momentum
2m leaves with v, momentum = 2mv
so m leaves with 2v, so that momentum = 2mv
Post by: ifraha18 on May 16, 2010, 07:18:24 pm
Post by: halosh92 on May 16, 2010, 07:27:54 pm
nov 2002 q9..?????
check for homogenity ;D
Post by: astarmathsandphysics on May 16, 2010, 07:37:19 pm
Posts: 139
Re: physics mcq help needed! urgent!
« Reply #125 on: Today at 06:02:16 PM »
Quote Modify Remove Split Topic
Quote from: ruby92 on Today at 11:05:50 AM
M/J 2009
10 13 20 33
O/N 2009
10 14 13 29
20 is maxima n*2?
21 why is it not B??
Post by: ruby92 on May 16, 2010, 07:53:23 pm
Post by: halosh92 on May 16, 2010, 08:08:30 pm
i dditn get the june 2002 q35..can u xplain agn.?
ok c over all its 5V the first resistor gets 2 volts, the second gets 1 volts, the 3rd gets 2volts also
so the 1st and 2nd resistors have same voltage, and same resistances
got it?
Post by: astarmathsandphysics on May 16, 2010, 08:43:35 pm
Post by: astarmathsandphysics on May 16, 2010, 08:48:38 pm
https://studentforums.biz/index.php/topic,7771.msg206250.html#msg206250
20 Y=Fl/Ae so F=YAe/l Q has half the area and twice the length so 1/4 of the tension
33 I=V/R=4.2/18=0.47A
Post by: astarmathsandphysics on May 16, 2010, 08:55:53 pm
60*0.5 =30*3 -30*v v=(30-90)/-30=2m/s
13Tension =torque/radius of Q=3/0.1
torque on P=F*r=30*0.15=3.5
14 A horizontal component of velocity =r sin45=v/sqrt(2)
at top of motion this is the only component of velocity and sqyares to give factor 1/2
29 A use F=Eq
Post by: ifraha18 on May 16, 2010, 08:56:42 pm
ok c over all its 5V the first resistor gets 2 volts, the second gets 1 volts, the 3rd gets 2volts also
so the 1st and 2nd resistors have same voltage, and same resistances
got it?
oo Thanks..yea...
Post by: ifraha18 on May 16, 2010, 09:10:48 pm
Post by: halosh92 on May 16, 2010, 09:21:39 pm
q35 nov 2002.??
when u increase the resistance in the variable resistor, voltage increases
voltage then DECREASES in the wire
then
R is directly proportional to length "L"
when resistance of variable increases then the length has to increase...thus it moves to Y
Post by: astarmathsandphysics on May 16, 2010, 09:22:45 pm
We need to increase the pd across the wire bey increasing its resistance, hence its length
Post by: halosh92 on May 16, 2010, 09:25:01 pm
10) momentum is conserved, take momentum for each side seperately
2m will have speed u
and m will have speed 2u, so that the product of both equations will give 2mu(same momentum)
ke
x= (2u)2 y=(u)2
so dividin both will give 4u/u which is 4/1
By the way the answer is wrong
its supposed to be : 2
u have to use (ke) formula here so the 4 and 2 cancel each other when u do the calculations.
Post by: neno on May 16, 2010, 11:21:00 pm
#may/june 2008-Q26,Q22,Q16,Q14but the answer for 22 in the marking schemes is B for 22 thts wat i dont get
26 twice as far so 1/2^2 =1/4 the intensity
27 D the wavelength is 4 x distance to wall cos node to antinode is 1/4 wavelength
22 c not elastic cos is deforming
14 A take moments about top of ladder against wall
16 A moves in direction of the force distance s so W=Fs
A
Post by: astarmathsandphysics on May 16, 2010, 11:31:28 pm
Post by: neno on May 16, 2010, 11:36:15 pm
Post by: ifraha18 on May 16, 2010, 11:42:29 pm
Post by: neno on May 16, 2010, 11:45:13 pm
Post by: ifraha18 on May 16, 2010, 11:46:37 pm
Post by: ifraha18 on May 16, 2010, 11:49:38 pm
Post by: neno on May 16, 2010, 11:50:49 pm
Post by: ifraha18 on May 16, 2010, 11:52:28 pm
Post by: astarmathsandphysics on May 16, 2010, 11:54:13 pm
Post by: ifraha18 on May 16, 2010, 11:54:52 pm
Post by: ifraha18 on May 16, 2010, 11:55:38 pm
Post by: neno on May 17, 2010, 12:00:05 am
workdone=energy and workdone=force times the distance in the same direction at the force applied so since the force is acting in the same direction as the distance s so the enegy is equal to fs...and when the charge moves 4rm x to y then the distance from the sorce increases and more the distace increases the less the force is thts y it decreases
Post by: ifraha18 on May 17, 2010, 12:03:24 am
Post by: neno on May 17, 2010, 12:04:15 am
notice tht the forces F are acting on the same place so thts the couple
while Wx2a-Wxa shud be equal to the couple
Wx2a-Wxa=Fxh(in couple u jst take 1 force X the distane between them)
therefore W2a=Fh+Wa
Post by: ifraha18 on May 17, 2010, 12:06:54 am
Post by: neno on May 17, 2010, 12:07:40 am
so in this case cos theta X v shud be equal to the adjacent which it u
so cos theta x v=u
v=u/cos theta
Post by: ifraha18 on May 17, 2010, 12:11:35 am
Post by: ifraha18 on May 17, 2010, 12:15:17 am
Post by: neno on May 17, 2010, 12:16:33 am
oct/nov 2007 Q37,Q32,Q25
Post by: neno on May 17, 2010, 12:16:49 am
so the volume of a cylinder is its lengthXthe crosssectional area
so for x imagine the area is 1 and the length is 1 so the volume is 1
but for y the length is 4 but it still has the same volume so therefor 4Lxa quater area will give the same volume which is 1
and resistance in a wire is equal to length over area
so in this case 4/0.25 which is equal to 16
Post by: ifraha18 on May 17, 2010, 12:17:24 am
Post by: superduper2009 on May 17, 2010, 12:20:59 am
(cie)
thanks alot :D
Post by: ifraha18 on May 17, 2010, 12:23:43 am
Post by: neno on May 17, 2010, 12:25:23 am
oct nv 2007 32. as the lyt increases resistance acros ldr decreases n do does the voltmeter reading. so its Abut isnt it tht the resistance in a ldr depends on the lightintensity the more the light the more the intensity??
Post by: ifraha18 on May 17, 2010, 12:27:37 am
strain energy is 1/2 *f*l
here the graph is btween l and f..so energy is area above the line...
tht is 1/2*(.4_.2)*25
tht is 2.5J
Post by: ifraha18 on May 17, 2010, 12:28:23 am
Post by: ifraha18 on May 17, 2010, 12:42:49 am
dsin thetha=n lambda
d sin45=3lambda
d=3lambda/sin45
d=3root2 lambda
the maximum value of sinetheha is 1
so fr highest order...nlamda/d<=sinthetha
nlamda/3root2lambda <=1
n/3root2<=1
n<=3root2
n<=4.24
so highest order is 4
Post by: ifraha18 on May 17, 2010, 12:46:07 am
Post by: neno on May 17, 2010, 01:01:42 am
q 4,32 of nov 2008?>>>
for 4 i have no clue but 32 i can solve
1 copper wire has resistance 10 length 1000m
resistance =length /area
10=1000/area
area=1000/10
therefore area =100
6 wires so area 600
length the same so therefore 1000/600
which is equal to 1.6
Post by: neno on May 17, 2010, 01:03:22 am
Post by: neno on May 17, 2010, 01:10:25 am
Q9(mayjune 2004)
Post by: cashem'up on May 17, 2010, 03:55:24 am
Q40 mayjune 2007??
we know that E = V/d and E= F/q
qE=F , ma=qE , a=qe/m now when we want lowest speed acceleration should be least ;)
so take particle with smallest charge to mass ratio......take E constant here as field will be same......
;D ;D ;D
Post by: cashem'up on May 17, 2010, 04:11:11 am
Q3,Q21(oct/nov 2006)
Q9(mayjune 2004)
q3 o/no6
we have to use base units
so elecitric field strength = F/Q
so ma/q now m is kg a is m/s2 and Q is C
so in this equation we get kgms-2C-1
Q9
lets look first at vertical u=0 g=10 s=1.25 t=?
so 1.25=0.5at2
2.5/10=t2
0.25=t2
t=0.5
then applying to horizontal
s=10 u=? t=0.5 a=0
s=ut
u=10/0.5
u=20
Post by: sabrina on May 17, 2010, 05:49:07 am
my doubt is on oct\nov 2007 Q7. why it cant be A?
Post by: halosh92 on May 17, 2010, 07:04:47 am
for 4 i have no clue but 32 i can solve
1 copper wire has resistance 10 length 1000m
resistance =length /area
10=1000/area
area=1000/10
therefore area =100
6 wires so area 600
length the same so therefore 1000/600
which is equal to 1.6
Q4:
(2.02+1.98)/2
to get the current value
answer = 2
(1/100)*2=0.02
then because u added in the beginning then u have 2 add uncertainty, this is the rule,
0.02+0.02=0.04
so ans is D
Post by: halosh92 on May 17, 2010, 07:26:08 am
for 4 i have no clue but 32 i can solve
1 copper wire has resistance 10 length 1000m
resistance =length /area
10=1000/area
area=1000/10
therefore area =100
6 wires so area 600
length the same so therefore 1000/600
which is equal to 1.6
for question 32.....dont u consider the steel core resistance???
Post by: cashem'up on May 17, 2010, 07:53:03 am
so
1/r= 1/10 + 1/10 + 1/10 + 1/10 + 1/10 + 1/10 + 1/100
so R=1.64
so R=1.6
then
Post by: halosh92 on May 17, 2010, 08:31:42 am
well yea actually i think u do it in a slightly different way......THE MAIN THING HERE IS THE WIRES ARE PARALLEL...................
so
1/r= 1/10 + 1/10 + 1/10 + 1/10 + 1/10 + 1/10 + 1/100
so R=1.64
so R=1.6
then
MUCH EASIER
THS ::)
Post by: da_rockstar on May 17, 2010, 08:48:15 am
i have a quetion....when we talk about the kinetic energy of a electron in a electric field is there a formula stating that:
kinetic energy=potential difference across the plates * charge of the electron.
another question which i wanted to clear was that for example i saw a question that like a specific amount of electrons and protons were moving in oppisite directions in the same wire. they asked about the total charge on it.
so can you explain whether we subtract the charges or do we add them up....
thanks.
Post by: cashem'up on May 17, 2010, 08:53:25 am
hm....but can you please explain why you took those wires as parralel?????1. Because how else would they be transmitted.......u cant have them in series.........
i have a quetion....when we talk about the kinetic energy of a electron in a electric field is there a formula stating that:
kinetic energy=potential difference across the plates * charge of the electron.
another question which i wanted to clear was that for example i saw a question that like a specific amount of electrons and protons were moving in oppisite directions in the same wire. they asked about the total charge on it.
so can you explain whether we subtract the charges or do we add them up....
thanks.
2. no there is isnt a formula like that but we now V/d = F/q so if if distance is constant then VQ=F where as VQ=ma..... now a= VQ/m now since we now the acceleration of particles its easy to compare the kinetic energy or if distance or time given the velocity and ke. itself can be deduced.....
;D ;D ;D
Post by: da_rockstar on May 17, 2010, 09:04:18 am
q2.
but can't we say this:
K.E=F*d
F=QE but E is V/d
F=QV/d
K.E hence becomes QV right?
because i read in mark scheme that changing the distance of electric field strength does not effect the speed of the particle.
an what about my last one...can u help me in it?
thanks
Post by: halosh92 on May 17, 2010, 09:16:16 am
the spheres collide and move off with speeds VA and VB, both in the same direction as the intial direction of sphere A.
which equation applies to an elastic collision?
1) UA + UB =VB-VA
2)UA - UB = VB-VA
3)UA-UB=VB + VA
4) UA + UB = VB +VA
someone plzz explain
thxx :)
Post by: ruby92 on May 17, 2010, 09:27:43 am
Q) two spheres A and B approach each other along the same straight line with speeds UA and UB.
the spheres collide and move off with speeds VA and VB, both in the same direction as the intial direction of sphere A.
which equation applies to an elastic collision?
1) UA + UB =VB-VA
2)UA - UB = VB-VA
3)UA-UB=VB + VA
4) UA + UB = VB +VA
someone plzz explain
thxx :)
----->uA UB<------ before collision
after collison
VA-------> VB------->
taking ---> as positive
UA-(-UB)=VB-VA
UA+UB=VB-VA
Post by: halosh92 on May 17, 2010, 09:38:42 am
----->uA UB<------ before collision
after collison
VA-------> VB------->
taking ---> as positive
UA-(-UB)=VB-VA
UA+UB=VB-VA
fankyou ;)
Post by: ruby92 on May 17, 2010, 10:07:49 am
Post by: shamanking on May 17, 2010, 10:51:12 am
Post by: halosh92 on May 17, 2010, 11:06:43 am
M/j 2007 27??
A
well because first of all u should consider the direction of the stationary wave.
-------> and <---------
and this applies only to A
also consider the amplitude at first long arror, which mean high amplitude which means its an antinode....then short arrows, mean short amplitude, thats a node ull find another pair also if u look carefully
thats it. :)
Post by: Phosu on May 17, 2010, 12:21:17 pm
Post by: cashem'up on May 17, 2010, 12:36:07 pm
q1. so u mean that when wires are put together like this we always consider them as parallel?
q2.
but can't we say this:
K.E=F*d
F=QE but E is V/d
F=QV/d
K.E hence becomes QV right?
because i read in mark scheme that changing the distance of electric field strength does not effect the speed of the particle.
an what about my last one...can u help me in it?
thanks
well yea ur method is also rite in physics u can dervie everything from everything lol ;D ;D ;D
yea for the next part i dont know the question but if i an not wrong to find the total charge u have to add them
q of proton + q of electron
electron will be negative so
Q1+(-Q2)
so Q1-Q2
in a way ur subtracting them but i think u got my point
Post by: ruby92 on May 17, 2010, 01:19:29 pm
A
well because first of all u should consider the direction of the stationary wave.
-------> and <---------
and this applies only to A
also consider the amplitude at first long arror, which mean high amplitude which means its an antinode....then short arrows, mean short amplitude, thats a node ull find another pair also if u look carefully
thats it. :)
tnkxxx :D
Post by: hesho21 on May 17, 2010, 02:17:04 pm
Post by: halosh92 on May 17, 2010, 02:38:12 pm
Guys plz I need help in No13 plz in Nov09,qp11 attached here
which question?
Post by: halosh92 on May 17, 2010, 02:50:08 pm
Q5
Q8
someone plz explain
thx
Post by: ruby92 on May 17, 2010, 02:57:45 pm
22
Post by: halosh92 on May 17, 2010, 03:01:41 pm
M/j 2006
22
calculate first the area for the triangle then calculate area of trapezium and then add
Post by: [Spy] on May 17, 2010, 03:02:18 pm
2003 june
Q5
Q8
someone plz explain
thx
Q5) my teacher even couldnt solve this, its something very weird :S
but here's my solution.....3% of 330 is 10, which is to two significant results, and therefore answer should be to two S.F meaning its C, but its a very stupid question and thats the only time it came :S
Q8) as you can see, the first stage involves a steady increase in velocity, meaning that the distance has to be increasing WITH AN INCREASING RATE. get it? since the velocity is the are in the D-T graph, then for each second there should be increasing area because velocity is increasing, and A shows this. if you look at the second part, its steady velocity meaning its not changing and therefore there is going to be a constant equal change in distance every second, and that's shown by a straight line. and for the last party it velocity is decreasing, BUT THAT DOES NOT MEAN DISTANCE IS INCREASING! you probably put A right? no the answer is C because in the third part it shows a increasing distance BUT WITH A DECREASING RATE until it doesnt change anymore (straight line)
hope its clear :D
Post by: halosh92 on May 17, 2010, 03:30:26 pm
Post by: [Spy] on May 17, 2010, 03:38:44 pm
same paper Q15
well, if you look at B, X Air resistance is correct because as an objects fall from a height, the total net force on it starts decreasing because air resistance starts from zero and then increases gradually which is shown in the graph for X, but in B it says Weight for force Y, weight does not change obiously no matter what unless your on an inclided plane ofcourse,
answer cant be C because we said C has to be resistance.
D cant be the answer because neither is X resitance and Y is weight which we said doesnt change here
as for A, then X is air resistance which is correct, and plus, force Y is net force i.e resultant force which like i said above, will start decreasing from a high value as resistance increases because as the object falls the resistance will keep increasing and therefore the total net force downwards decreases.
:)
Post by: halosh92 on May 17, 2010, 04:08:23 pm
well, if you look at B, X Air resistance is correct because as an objects fall from a height, the total net force on it starts decreasing because air resistance starts from zero and then increases gradually which is shown in the graph for X, but in B it says Weight for force Y, weight does not change obiously no matter what unless your on an inclided plane ofcourse,thankyou
answer cant be C because we said C has to be resistance.
D cant be the answer because neither is X resitance and Y is weight which we said doesnt change here
as for A, then X is air resistance which is correct, and plus, force Y is net force i.e resultant force which like i said above, will start decreasing from a high value as resistance increases because as the object falls the resistance will keep increasing and therefore the total net force downwards decreases.
:)
same paper Q36
i dont get the direction :S
and Q40
Post by: [Spy] on May 17, 2010, 04:31:06 pm
thankyou
same paper Q36
i dont get the direction :S
and Q40
Q36) it simple as that the electric field direction is always from positive to negative, and you can see that at the upper plate has a NEGATIVE voltage meaning the direction will be from Q to P, and so the answer is D :)
Q40) as we know a proton has the same charge as an electron (the value) thats why an atom is neutral, therefore here, we have to obtain a combination of up and down quarks so that achieve a value of "e" exactly, equal to the charge of the electron.
for A, (0*2/3)+(3*-1/3)= -1, it cant be the answer because we have to obtain a positive value since its a proton!
for B, (1*2/3)+(1*-1/3)= 1/3 - Not Possible because we need a value of exactly positive 1.
for C, (1*2/3)+(2*-1/3)= 0 - Not Possible because we need a value of exactly positive 1.
for D, (2*2/3)+(1*-1/3)= 3/3 = 1 and therefore D is the answer :D
Post by: halosh92 on May 17, 2010, 04:41:50 pm
Q36) it simple as that the electric field direction is always from positive to negative, and you can see that at the upper plate has a NEGATIVE voltage meaning the direction will be from Q to P, and so the answer is D :)
Q40) as we know a proton has the same charge as an electron (the value) thats why an atom is neutral, therefore here, we have to obtain a combination of up and down quarks so that achieve a value of "e" exactly, equal to the charge of the electron.
for A, (0*2/3)+(3*-1/3)= -1, it cant be the answer because we have to obtain a positive value since its a proton!
for B, (1*2/3)+(1*-1/3)= 1/3 - Not Possible because we need a value of exactly positive 1.
for C, (1*2/3)+(2*-1/3)= 0 - Not Possible because we need a value of exactly positive 1.
for D, (2*2/3)+(1*-1/3)= 3/3 = 1 and therefore D is the answer :D
thx !! the second question is such simple common sense -.- :o
Post by: [Spy] on May 17, 2010, 04:48:19 pm
thx !! the second question is such simple common sense -.- :o
haha well there's always a common sense way and a scientific way :P
Post by: halosh92 on May 17, 2010, 04:53:52 pm
hahah too sad ive got neither...
haha well there's always a common sense way and a scientific way :P
2003 nov
Q12
2009 NOV variant 1
Q13
Post by: ifraha18 on May 17, 2010, 05:09:54 pm
elastic collison so velocity of approach is equal to velocity of separation..
ux+uy=vx+vy
Post by: ifraha18 on May 17, 2010, 05:14:58 pm
plzz someone?
Post by: halosh92 on May 17, 2010, 05:17:19 pm
2003 nov q12...
elastic collison so velocity of approach is equal to velocity of separation..
ux+uy=vx+vy
if we take this ----------> as +
and this <------------- as -
we dont get that answer :S
Post by: ifraha18 on May 17, 2010, 05:49:01 pm
Post by: ifraha18 on May 17, 2010, 05:51:18 pm
plzz someone?
Post by: da_rockstar on May 17, 2010, 05:58:27 pm
yea for the next part i dont know the question but if i an not wrong to find the total charge u have to add them
q of proton + q of electron
electron will be negative so
Q1+(-Q2)
so Q1-Q2
in a way ur subtracting them but i think u got my point
lol..yeah you are right dude....:D we derive random stuff whenever we need it...lol.. got my biology practical tommorow....and this year i didn't do any practical...lol...hope all goes well. :D
Post by: nid404 on May 17, 2010, 06:41:24 pm
nv 2007 q 2,11 and 40..??
plzz someone?
2) approx diameter of an atom/ion is to the power of 10^-15 ...you have no choice but to know this
11) B Because there also a normal contact force acting on the wheels vertically up. And there's the forward force by the engine. Their resultant would be B
Post by: ifraha18 on May 17, 2010, 06:56:20 pm
and answer fr 40 is A..alpha particle.????
Post by: nid404 on May 17, 2010, 06:59:13 pm
bt the answer fr 2 is A!!!10^-15..
and answer fr 40 is A..alpha particle.????
oops my bad. A it is...I edited my post. Well what i wanted to say was you gotta memorize it
Post by: ifraha18 on May 17, 2010, 07:01:27 pm
thnkss a bunc..:)
Post by: nid404 on May 17, 2010, 07:02:22 pm
Post by: highly_ambitious on May 17, 2010, 07:03:07 pm
elastic collision mean that spheres should stick together n move in the direction of the heavier mass? innit?
Post by: nid404 on May 17, 2010, 07:07:59 pm
The ball is first moving towards the racket with a velocity of 20m/s. The ball hits the racket and moves in the opp direction with a velocity of 30m/s
so the change in momentum is given by
mv-mu
v=30m/s
u=-20m/s (- sign cause it's in the opp direction)
30X0.1kg-(-20X0.1kg)=5kgm/s
so B
Post by: highly_ambitious on May 17, 2010, 07:10:04 pm
huh?
The ball is first moving towards the racket with a velocity of 20m/s. The ball hits the racket and moves in the opp direction with a velocity of 30m/s
so the change in momentum is given by
mv-mu
v=30m/s
u=-20m/s (- sign cause it's in the opp direction)
30X0.1kg-(-20X0.1kg)=5kgm/s
so B
can u tell me where is this question?
Post by: nid404 on May 17, 2010, 07:10:44 pm
Post by: highly_ambitious on May 17, 2010, 07:11:38 pm
you said june 09 Q9 right?
no yarr...i said m/j 2002 q9.
Post by: nid404 on May 17, 2010, 07:15:54 pm
no yarr...i said m/j 2002 q9.
oiii...my bad.
well for that question
they won't stick together, they possibly can't because they both have the same mass and same velocity but are moving towards each other. For them to stick, either one has to have a greater mass or a greater velocity
So B is the answer
because in an elastic collision, k.e is conserved
before collision k.e= 1/mv2 + 1/2 mv2= mv2
so after collision this k.e will be conserved.
The other statements ain't possible either
Post by: halosh92 on May 17, 2010, 07:18:47 pm
oiii...my bad.
well for that question
they won't stick together, they possibly can't because they both have the same mass and same velocity but are moving towards each other. For them to stick, either one has to have a greater mass or a greater velocity
So B is the answer
because in an elastic collision, k.e is conserved
before collision k.e= 1/mv2 + 1/2 mv2= mv2
so after collision this k.e will be conserved.
The other statements ain't possible either
i have a question.
for the ke..shouldnt we consider their opposite directions here???
so one would be (+) and the other (-) ??
Post by: highly_ambitious on May 17, 2010, 07:23:27 pm
oiii...my bad.
well for that question
they won't stick together, they possibly can't because they both have the same mass and same velocity but are moving towards each other. For them to stick, either one has to have a greater mass or a greater velocity
So B is the answer
because in an elastic collision, k.e is conserved
before collision k.e= 1/mv2 + 1/2 mv2= mv2
so after collision this k.e will be conserved.
The other statements ain't possible either
yeah right!...Thanks
same paper q28..i always get confused in question which relate to wave. In this question too i got stuck. In the fig, point X is shown above 'O' so the path difference should be 'n' whole number. Therefore, we get a bright fringe. Thus the path difference should be S2X - S1X = lambda .
then why is the answer C..can't get!!
Post by: nid404 on May 17, 2010, 07:26:34 pm
i have a question.
for the ke..shouldnt we consider their opposite directions here???
so one would be (+) and the other (-) ??
energy is a scalar quantity
Post by: nid404 on May 17, 2010, 07:31:57 pm
yeah right!...Thanks
same paper q28..i always get confused in question which relate to wave. In this question too i got stuck. In the fig, point X is shown above 'O' so the path difference should be 'n' whole number. Therefore, we get a bright fringe. Thus the path difference should be S2X - S1X = lambda .
then why is the answer C..can't get!!
I'm not too good with waves but...
there's a formula for such type of question
for destructive interference the phase difference should be
so if you rearrange the eqn (i substituted phase difference as
path difference= S2X-S1X
so you get
Post by: highly_ambitious on May 17, 2010, 07:40:59 pm
I'm not too good with waves but...
there's a formula for such type of question
for destructive interference the phase difference should be
so if you rearrange the eqn (i substituted phase difference as=
path difference= S2X-S1X
so you get
thank you so much!...it was v.very helpful!
Post by: highly_ambitious on May 17, 2010, 07:42:27 pm
thank you so much!...it was v.very helpful!
can u explain me the formula I= ka2...? what does k mean here? n in which situation do we apply this formula?
Post by: nid404 on May 17, 2010, 07:44:25 pm
can u explain me the formula I= ka2...? what does k mean here? n in which situation do we apply this formula?
k is a constant.
When they ask you to find intensity or amplitude of a wave and give one of the values
Post by: highly_ambitious on May 17, 2010, 07:46:35 pm
k is a constant.
When they ask you to find intensity or amplitude of a wave and give one of the values
Thanks!
Post by: nid404 on May 17, 2010, 07:48:58 pm
Thanks!
not a problem :)
Post by: zxcvbnm on May 17, 2010, 07:53:10 pm
Post by: highly_ambitious on May 17, 2010, 07:58:59 pm
Post by: zxcvbnm on May 17, 2010, 08:01:19 pm
Post by: highly_ambitious on May 17, 2010, 08:08:47 pm
Microwaves 10^-1 to 10^-4
Infra-red 10^-4 to 10^-6
Visible wave 10^-6 to 10^-7
UV waves 10^-7 to 10^-9
X-ray wave 10^-9 to 10^-12
Gamma ray 10^-12 to 10^-16
Post by: highly_ambitious on May 17, 2010, 08:09:50 pm
Radio waves 10^4 to 10^-1
Microwaves 10^-1 to 10^-4
Infra-red 10^-4 to 10^-6
Visible wave 10^-6 to 10^-7
UV waves 10^-7 to 10^-9
X-ray wave 10^-9 to 10^-12
Gamma ray 10^-12 to 10^-16
the unit of the wave length is in metres (m).
Post by: zxcvbnm on May 17, 2010, 08:12:23 pm
Radio waves 10^4 to 10^-1
Microwaves 10^-1 to 10^-4
Infra-red 10^-4 to 10^-6
Visible wave 10^-6 to 10^-7
UV waves 10^-7 to 10^-9
X-ray wave 10^-9 to 10^-12
Gamma ray 10^-12 to 10^-16
thankyou loads!!!!!
Post by: hesho21 on May 17, 2010, 08:14:55 pm
which question?Hey I meant number 13 in the november 09 paper 11 :D Thanks in advance
Post by: zxcvbnm on May 17, 2010, 08:19:49 pm
Post by: astarmathsandphysics on May 17, 2010, 08:54:11 pm
50+5=0+10+KE(final)
KE(final)=45
Post by: superduper2009 on May 17, 2010, 09:01:03 pm
10,11,27,30
Also can someone explain the following formulas --->
i)dsin(theta)=n(lambda)
ii) lambda= ax/D
also what is the forumla of finding work done from a graph of F vs extension, (is it area under graph???)
And what is the unit of Young's modulus....
Also how do we know from a graph whether a material is ductile, plastic elastic etc etc
Post by: zxcvbnm on May 17, 2010, 09:04:12 pm
GPE(initailly)+KE(initail)=GPE(finallt)+work done afgainst friction+KE(final)
50+5=0+10+KE(final)
KE(final)=45
ok thanx but the final g.p.e shouldnt be zero, should it? the object is still at a height...and 50 is the loss in g.p.e, no?
also, please explain june 03, q 20 and 22
Post by: vanibharutham on May 17, 2010, 09:08:59 pm
d = slit width
theta = angle of the diffraction
n = diffraction order , whether it is 1st maxima, 2nd maxima etc
lambda = wavelength
you use the formula for single slit diffraction
ii) lambda= ax/D
lambda = wavelength
a = distance between slits/ appertures
x = fringe separation
D = distance of slits from screen/eye/ receiver
this formula is used when you deal with Young's Double Slits and the double slit interference fringes - they form a regular pattern of maxima's...regular FRINGES is what they are called
also what is the forumla of finding work done from a graph of F vs extension, (is it area under graph???)
Yes, area under graph
And what is the unit of Young's modulus....
Pascals or N/m²
Also how do we know from a graph whether a material is ductile, plastic elastic etc etc
Ductile = the graph has a large plastic deformation region
elastic = straight line in the Hooke's Law Region... anything after that it is plastic
Toughness = the greater the area under a curve the tougher the material
Brittle = straight line and no plastic deformation, just a sudden SNAP
any others?
Post by: halosh92 on May 17, 2010, 09:12:43 pm
Can anyone solve and explain the following questions to me please --- (all are in october/november 2008 paper 1 cie physics)
10,11,27,30
Also can someone explain the following formulas --->
i)dsin(theta)=n(lambda)
ii) lambda= ax/D
also what is the forumla of finding work done from a graph of F vs extension, (is it area under graph???)
And what is the unit of Young's modulus....
Also how do we know from a graph whether a material is ductile, plastic elastic etc etc
Q11)
T=tension
A=acceleration
m=mass
T-6=8a
2*9.8 -T=2a
therefore (solve simultaneously)
13.6=10a
1.36=a
nearest to answer A
Post by: samin6n on May 17, 2010, 09:13:50 pm
Post by: astarmathsandphysics on May 17, 2010, 09:14:07 pm
2003 jun
20 if child can ;lower pressure by 10% there is a net pressure 0.1P_0 =dgh wehere d=density so h=p_0/dg
22 1 spring removed so extension is 3x/2 now weight is doubled so extension is doubled to 3x
Post by: halosh92 on May 17, 2010, 09:19:40 pm
Can anyone solve and explain the following questions to me please --- (all are in october/november 2008 paper 1 cie physics)
10,11,27,30
Also can someone explain the following formulas --->
i)dsin(theta)=n(lambda)
ii) lambda= ax/D
also what is the forumla of finding work done from a graph of F vs extension, (is it area under graph???)
And what is the unit of Young's modulus....
Also how do we know from a graph whether a material is ductile, plastic elastic etc etc
Q27) as its microwaves then its electromagnetic wave..so speed= 3*10^8
v= f lamda
lambda:
from one antinode to the next is 15mm but thats half a wavelength so one full wavelngth is 30mm
now apply the equation:
(3*10^8)/([15*2]/1000)
make sure to change mm to m by dividing by 1000 .
answer is C
Post by: halosh92 on May 17, 2010, 09:23:10 pm
Q27) as its microwaves then its electromagnetic wave..so speed= 3*10^8
v= f lamda
lambda:
from one antinode to the next is 15mm but thats half a wavelength so one full wavelngth is 30mm
now apply the equation:
(3*10^8)/([15*2]/1000)
make sure to change mm to m by dividing by 1000 .
answer is C
Q30) E=V/d
also E=F/q
equate:
V/d=F/q
we have to find "q"
so:
660/(15/1000)=F/(4.8*10^-19)
dont forget to change the 15mm to m thats why we divide by 1000
and simply cross multiply.
Post by: halosh92 on May 17, 2010, 09:28:08 pm
O/N 2004 Q 15 ..Please explain!!
ok c :
ke= 1/2mv^2
lets ignore the "m" for now
so we could make use of values here
lets take ke=2
solving:
2=1/2mv^2
sqrt4= 2=v
therefore v=2
if it increase by factor of 4 that means:
2*4=8
ke=1/2mV^2
8=1/2mV^2
sqrt16=4=V
V=4
then V/v = 4/2 = 2
Post by: superduper2009 on May 17, 2010, 09:43:42 pm
Q11)Thanks alot...
T=tension
A=acceleration
m=mass
T-6=8a
2*9.8 -T=2a
therefore (solve simultaneously)
13.6=10a
1.36=a
nearest to answer A
By the way what are the formulas that u used for getting the equations???
Post by: zxcvbnm on May 17, 2010, 09:49:01 pm
GPE is relative. I can say GPE is zero relative to the initial position where it was +50
2003 jun
20 if child can ;lower pressure by 10% there is a net pressure 0.1P_0 =dgh wehere d=density so h=p_0/dg
22 1 spring removed so extension is 3x/2 now weight is doubled so extension is doubled to 3x
ohh i see...thanx alot!
Post by: halosh92 on May 17, 2010, 09:53:57 pm
Thanks alot...
By the way what are the formulas that u used for getting the equations???
F=ma
ure welcome ;)
Post by: superduper2009 on May 17, 2010, 10:01:46 pm
one more doubt :S....
in the case of
dsin(theta) = n(lambda)
how do we calculate d when 1 meter has 1000 gratings is it simply (1/1000)????
Post by: halosh92 on May 17, 2010, 10:11:06 pm
Thanks SOOOOOOOOO MUCH TO ALL OF U GUYS...
one more doubt :S....
in the case of
dsin(theta) = n(lambda)
how do we calculate d when 1 meter has 1000 gratings is it simply (1/1000)????
could u like post the exact question for that?
i think so thats the way u do it ..unless there are some other typical questions.
Post by: superduper2009 on May 17, 2010, 10:12:20 pm
and best of luck 4 ur exam :D
Post by: halosh92 on May 17, 2010, 10:21:02 pm
doubt:
june 2006 Q9
Post by: superduper2009 on May 17, 2010, 10:31:35 pm
The maxima and minima would on the graph i.e. A and C would occur at the middle of the motion... where speed is maximum..
therefore u can cross out A and C,
deciding between B and D ---
u know that at both points B and D the velocit is zero...
but u have to think... for the minimum point on the movement... the gradient at the point of the graph has to be negative.. (decreasing) ... and at point B.. the gradient (of tangent) is negative
hope it helps :D
Post by: halosh92 on May 17, 2010, 10:36:05 pm
The answer is B
The maxima and minima would on the graph i.e. A and C would occur at the middle of the motion... where speed is maximum..
therefore u can cross out A and C,
deciding between B and D ---
u know that at both points B and D the velocit is zero...
but u have to think... for the minimum point on the movement... the gradient at the point of the graph has to be negative.. (decreasing) ... and at point B.. the gradient (of tangent) is negative
hope it helps :D
but the answer is D :(
Post by: superduper2009 on May 17, 2010, 10:49:17 pm
ur right...
i gt it....between 0 and B the mass is moving upwards due to the positive velocity then it starts moving downwards.... C is the middle of the motion... and the mass is moving downwards...and then at D the mass has zero velocity and is at the lowest point of motion
Post by: ifraha18 on May 17, 2010, 10:49:38 pm
Post by: superduper2009 on May 17, 2010, 11:00:01 pm
s=0.5g t^2
therfore -->
t = (2s/g)^.5
time to fall 40m = (2(40)/9.81)^0.5 = 2.85
time to fall 30 m = (2(30)/9.81)^0.5 = 2.47
2.85 - 2.47 = 0.38... answer is A
:D
Post by: halosh92 on May 17, 2010, 11:00:21 pm
q8 n 10..june 2007..??plz someone.???
Q8) first find for the 40m
s=40
u=0
a=9.8
s=ut +1/2at^2
s=1/2at^2
sqrt(40*2/9.8)= t
t1= 2.857
now find for the first 30m
same thing except substitute "s" with 30m
u will get=2.47
t2= 2.47
t1-t2= 2.857 - 2.47= 0.38
Post by: halosh92 on May 17, 2010, 11:02:25 pm
IMPULSE
Ft=mv-mu
F=mv-mu/t
F= p2 -p1/t2-t1
Post by: ifraha18 on May 17, 2010, 11:05:32 pm
thks fr de eighth
Post by: ifraha18 on May 17, 2010, 11:10:37 pm
Post by: superduper2009 on May 17, 2010, 11:10:58 pm
also momentum = Ft
mv=Ft
F=(mv)/t
Average F = change in momentum / change in time
t2-t1 is the change in time...
change in momentum is P2-P1
therfore the answer is
p2-p1/t2-t1
the answer is B
Post by: ifraha18 on May 17, 2010, 11:11:56 pm
nd q 33 of june 2007 as well..plz.?
Post by: halosh92 on May 17, 2010, 11:14:28 pm
q33 10 june 2007???
the voltage in parallel is same...
now first find V1
2/10 x 5 = 1
and V2
2/5 x 3 = 1.2
and now V1-V2=1-1.2 = -0.2
Post by: ifraha18 on May 17, 2010, 11:17:18 pm
i am nt good wid circuits how can i solve em properli!!!...??wht should i do wid circuits
Post by: superduper2009 on May 17, 2010, 11:18:57 pm
Post by: astarmathsandphysics on May 17, 2010, 11:19:44 pm
V_1 =pd between S and P=1/2*2=1V
V_2 =PD between S and Q= 3/(2+3)*2=1.2V
1-1.2=-0.2V
Post by: ifraha18 on May 17, 2010, 11:20:02 pm
10 -Momentum = mv
also momentum = Ft
mv=Ft
F=(mv)/t
Average F = change in momentum / change in time
t2-t1 is the change in time...
change in momentum is P2-P1
therfore the answer is
p2-p1/t2-t1
the answer is B
i know it is answered but the corect answer is p1-p2/t2-t1
Post by: ifraha18 on May 17, 2010, 11:22:28 pm
Post by: ifraha18 on May 17, 2010, 11:26:15 pm
Post by: neno on May 17, 2010, 11:35:03 pm
Post by: astarmathsandphysics on May 17, 2010, 11:35:30 pm
40 D cos it mhas the highest mass
Post by: superduper2009 on May 17, 2010, 11:37:14 pm
i know it is answered but the corect answer is p1-p2/t2-t1sorry my bad... it is p1 - p2...:D
Post by: ifraha18 on May 17, 2010, 11:44:23 pm
n 40 is c!!!!dts y i ws confused.
Post by: ifraha18 on May 17, 2010, 11:45:15 pm
sorry my bad... it is p1 - p2...:D
how do u get p1-p2.???
Post by: superduper2009 on May 17, 2010, 11:54:43 pm
Post by: neno on May 18, 2010, 12:05:30 am
Post by: superduper2009 on May 18, 2010, 12:08:27 am
Post by: neno on May 18, 2010, 12:10:42 am
Post by: superduper2009 on May 18, 2010, 12:11:50 am
Post by: neno on May 18, 2010, 12:13:19 am
Post by: ifraha18 on May 18, 2010, 12:26:36 am
Post by: zxcvbnm on May 18, 2010, 08:40:04 am
Post by: zxcvbnm on May 18, 2010, 08:41:28 am
Post by: zxcvbnm on May 18, 2010, 08:48:37 am
same paper, number 10
also, question 32
Post by: halosh92 on May 18, 2010, 09:13:42 am
november 02, question 9
check for homogenity
Post by: halosh92 on May 18, 2010, 09:21:56 am
same paper, number 10
Q32) for +1
R=V/I
I=45/1000 (convert from mA to A)
R=1/(45/1000)
=22 ohms which is nearest to 20
and about -1V
its always infinte
Post by: zxcvbnm on May 18, 2010, 09:45:29 am
Q32) for +1
R=V/I
I=45/1000 (convert from mA to A)
R=1/(45/1000)
=22 ohms which is nearest to 20
and about -1V
its always infinte
thankyou so much!
Post by: halosh92 on May 18, 2010, 09:46:42 am
thankyou so much!
np;)
Post by: thecandydoll on May 18, 2010, 09:53:06 am
Post by: ruby92 on May 18, 2010, 11:53:19 am
Post by: zxcvbnm on May 18, 2010, 11:56:49 am
Post by: sabrina on May 18, 2010, 12:07:59 pm
can someone plz help me with maj\june 2002 Q18. i m trying my level best but cant understand n do the question.
thanks in advance. :)
Post by: highly_ambitious on May 18, 2010, 12:13:35 pm
Post by: halosh92 on May 18, 2010, 12:18:52 pm
hi guys
can someone plz help me with maj\june 2002 Q18. i m trying my level best but cant understand n do the question.
thanks in advance. :)
consider p.e at P as X. So p.e at Q is (X-50) J
k.e at P is 5kJ...that means p.e+k.e at P is X+5 kJ and W.d against friction is 10kJ. therefore at the lowest point it has (X+5)-10 kJ of energy=X-5 kJ
p.e at Q is X-50...the difference is....k.e at Q is given by
X-5-(X-50)= 45kJ
PS.i didnt solve this someone else did
Post by: highly_ambitious on May 18, 2010, 12:55:53 pm
Post by: halosh92 on May 18, 2010, 01:00:39 pm
may/june q22..plz somebody help me in this question. I'm not getting the correct answer.
which year???
Post by: highly_ambitious on May 18, 2010, 01:05:29 pm
which year???
opps sorry m/j 2003 q22.
Post by: ruby92 on May 18, 2010, 01:43:06 pm
25
Post by: sabrina on May 18, 2010, 01:48:19 pm
Post by: halosh92 on May 18, 2010, 01:54:38 pm
O/n 2006
25
ok for this question between X and Y u will find one full wave that would be 2pie
from X to the beginning of that full wave the distance is 90 degree or pie/2 same thing
and from Y to the end of that full wave the distance is also 90 degrees or pie/2
add all of these together
90 degrees + 90 degrees= pie
pie + 2pie (the middle wave we found out) = 3 pie
therefore C
Post by: halosh92 on May 18, 2010, 03:26:34 pm
thxxx :D
Post by: ruby92 on May 18, 2010, 03:33:42 pm
nucleus is 10^-14
Post by: halosh92 on May 18, 2010, 04:00:53 pm
could someone give a tip on how to solve projectiles ???
Post by: ruby92 on May 18, 2010, 04:06:36 pm
Post by: halosh92 on May 18, 2010, 04:24:23 pm
m/j 2005 33 24 16 5 11
Q33) R= L/A
V=A *L
when u double the length
V/L=A
V/2L=A
back to the main equation
R=L/A
R=2L /V/2L
R=4L^2/V
V=A*L
substitute in the coloured equation
R= 4L^2/A*L
4L/A
L/A=R
therefore 4R so its D
Post by: astarmathsandphysics on May 18, 2010, 05:23:40 pm
5 2 square=2microseconds
16 max power=max slope which is between 2 and 3 seconds 30/1=30W
11 60m-40m=2m*v
v=10
Post by: superduper2009 on May 18, 2010, 05:27:53 pm
7, 13,20,24
And what is the formula to find a tension in a string... where u have the mass per unit length, the length of the string...etc etc
Thanks in advance..
superduper2009 :D
Post by: 3ishakay on May 18, 2010, 06:04:56 pm
question 32
plzzzz!! :(
Post by: ruby92 on May 18, 2010, 06:09:49 pm
may/june 2005it says 2mm^2 has a current of 10 A. you need to find the no of electrons passing through 2mm^2 in 1 second.
question 32
plzzzz!! :(
Q=It=10*1=10C
1e has a charge of 1.6*10^-19C
x electrons will have 10C
10*1/1.6*10^-19=6.3*10^23electrons
Post by: 3ishakay on May 18, 2010, 06:14:41 pm
it says 2mm^2 has a current of 10 A. you need to find the no of electrons passing through 2mm^2 in 1 second.
Q=It=10*1=10C
1e has a charge of 1.6*10^-19C
x electrons will have 10C
10*1/1.6*10^-19=6.3*10^23electrons
Thanks a bunch!!! =D
Post by: ruby92 on May 18, 2010, 06:19:29 pm
o/n 2005
7 why cant it be C (t1-t2)^2?why t1^2-t2^2 ??? ???
Post by: ifraha18 on May 18, 2010, 06:26:57 pm
q 7...
x=1/2 *at1^2
h+x=1/2*at2^2
substitute x in secnd
h+(1/2*at1^2)=1/2*at2^2
h=(1/2*at2^2) _(1/2*at1^2)
2h=a(t2^2 _t1^2)
a=2h/t2^2 _t1^2
Post by: highly_ambitious on May 18, 2010, 06:34:21 pm
Post by: ifraha18 on May 18, 2010, 06:36:25 pm
Post by: superduper2009 on May 18, 2010, 06:43:51 pm
P= density x g x h
in q 18... think when the right side increases by h, the left side decreases by h...
so the difference between the heights becomes 2h..
to calculate pressure... substitute 2h instead of h and you get
P = 2h x roh x g
which is D
Post by: superduper2009 on May 18, 2010, 06:46:34 pm
the voltage is 3-1.2 = 1.8... (cells connected in opposite directions so u subtract)
we know that I=V/R
V=1.8, R=9
I= 1.8/9 = 0.2 A
the answer is B
By the way
In May/June 2009 how do u do --->
7, 13,20,24
Post by: ruby92 on May 18, 2010, 06:54:31 pm
nv 2005
q 7...
x=1/2 *at1^2
h+x=1/2*at2^2
substitute x in secnd
h+(1/2*at1^2)=1/2*at2^2
h=(1/2*at2^2) _(1/2*at1^2)
2h=a(t2^2 _t1^2)
a=2h/t2^2 _t1^2
Thank You:)
Post by: halosh92 on May 18, 2010, 06:56:47 pm
Q 18 -->pressure of a liquid is defined asso u consider the direction of distance here...it doesnt make sense it should be difference in heights aint it?
P= density x g x h
in q 18... think when the right side increases by h, the left side decreases by h...
so the difference between the heights becomes 2h..
to calculate pressure... substitute 2h instead of h and you get
P = 2h x roh x g
which is D
Post by: ifraha18 on May 18, 2010, 06:58:42 pm
T in P=AEe/l
Q=(A/2*Ee)/2l
Q=AEe/4l
p/q= AEe/l divided by AEe/4l
p/q=4
fr 24 we knw dt the ditnce between an antinode and adjacent node is 1/4 lambda
Post by: ifraha18 on May 18, 2010, 07:02:09 pm
Thank You:)
ur welcme..:)
Post by: ruby92 on May 18, 2010, 07:04:03 pm
Post by: sweetie on May 18, 2010, 07:10:18 pm
nov05 Q24
nov07 Q35
any help is appreciated :)
Post by: ifraha18 on May 18, 2010, 07:12:32 pm
wavelength is halved so frnge spacing is halved dt is 1.5nm
further sli spacing is doubled n slit spacing is inversly rlted to frnge spacing so fringe spcing is further halfed to .75nm
Post by: ifraha18 on May 18, 2010, 07:16:07 pm
in nv 2005 24
amplitude doubled so intensity is 2I
further frequency is halved so intensity returns to I
Post by: superduper2009 on May 18, 2010, 07:19:17 pm
thanks in advance
Post by: ifraha18 on May 18, 2010, 07:21:24 pm
Post by: superduper2009 on May 18, 2010, 07:23:31 pm
Post by: ifraha18 on May 18, 2010, 07:27:24 pm
Post by: ifraha18 on May 18, 2010, 07:29:58 pm
for P T =AEe/l
forQ T=(A/2*Ee)/2l =AEe/4l
p/q = AEe/l divided by AEe/4l
p/q=4
A is area
E young modulus T tension
e extension
l length
Post by: ifraha18 on May 18, 2010, 07:30:41 pm
please, can you tell me what each letter in the equation stands for ...
u got it.??
Post by: superduper2009 on May 18, 2010, 07:43:49 pm
Post by: ifraha18 on May 18, 2010, 07:46:12 pm
Post by: ifraha18 on May 18, 2010, 07:54:54 pm
yeah...thanks alot :D
u needed june 2009 q13 as well..
so it is
F*1.2=900 *.2
f=150
Post by: ifraha18 on May 18, 2010, 07:56:22 pm
Post by: halosh92 on May 18, 2010, 08:18:59 pm
how do we find the power
is its the area or slope or wat exactly??
Post by: superduper2009 on May 18, 2010, 08:20:12 pm
Post by: halosh92 on May 18, 2010, 08:24:00 pm
power would be the gradient
thx BEST OF LUK EVERYONE 8)