Physics: Post your doubts here!

[beeloooo]

Hi everyone, AsSalamoAlaikum Wr Wb...

To get things organized in a better way, I am making this thread. As othewise, some queries remain unanswered!

So post your PHYSICS doubts in this thread. InshaAllah other people here will help me and you all.

NOTE: If any doubts in the pastpapers, please post the link! You can find links here!

Any Physics related notes and links will be added here in this post. Feel free to provide the links to your notes around the forum, or any other websites!
Thanks!
Jazak Allah Khair!

Physics Notes:

Some links & Notes - by destined007

As physics p1 MCQS YEARLY Solved [explaination]
Physics Practical Tips - by arlery

Notes for A2 Direct Sensing (Applications) - shared by sweetiepie

Physics Summarised Notes (Click to download)

AS and A-Level Physics Definitions

A2: Physics Revision notes - by smzimran

Paper:5 Finding uncerainty in log - by XPFMember

Physics Paper 5 tips - by arlery

Physics Compiled Pastpapers: <Credits to CaptainDanger for sharing this..>

Here are the compiled A level topical Physics questions in PDF form...

Paper 1 : http://www.mediafire.com/?tocg6ha6ihkwd

Paper 2 & Paper 4 : http://www.mediafire.com/?g65j51stacmy33c

(Source : http://www.alevelforum.com/viewtopic.php?f=15&t=14)

The physics p1 topical dont they have the answers with them ? please be kind to reply.

 

[Tkp]

http://papers.xtremepapers.com/CIE/Cambridge%20International%20A%20and%20AS%20Level/Physics%20(9702)/9702_w09_qp_11.pdf
Question 22 and 26 please!

for 22 apply the formula of Young modulus
FL/AX=E
SO WE Need to find the change in length
f=20,a=pie*(5*10^-4/2)^2
e=2*10^11
u will get 5*10^-4
and for percentage multiply by 100

 

[raamish]

see the cro rises to a maximum at a position X, falls to a minimum and then rises once again to a maximum at a
position Y. so the distance between the adjacent antinodes is .5lambda
so 33*2/100=lambda
v=flambda
and f is 500
so the time base for 1 div is .5ms
so it takes 4 div to complete a wave that means 4*.5
=2 ms
2/1000=1/500
and f=1/t
so it matches and the ans is B
Hope ur clear nw

hey in n07 to measure pressure we are using pressure gauge. it's saying not allow pressure meter or barometer. so in calculating pressure do we always use pressure gauge or sometimes pressure meter or barometer can be used. and in mark scheme there is a pt written difficulty in measuring amplitudes at small pressures. Use a large incident source. So i wrote that use high values of p so that a could be measures easily. So can u explain this mark scheme point. And another point that the window should be perpendicular to source. Should we write this point whenever something is being transmitted through a substance? And what is the purpose of the pt. these are a lot of questions sorry but plzz help

 

[Yousif Mukkhtar]

7. The component of acceleration is the acceleration due to gravity and that's the same always anywhere on Earth.
20. Choose a point and find the pressure due to P & Q at that same point. For example, any point on the second dotted line. The pressure due to Q will be = density of Q x g x h. The pressure due to P will be = density of Q x g x 2h. Cancel out g for both, you'll get density of Q = pressure/h, and density of P = pressure/2h.
25. Points on a wave vibrate up and down, and don't move to the right. A trough is travelling towards P, so P is going down.

THank you alot for the help.

 

[Yousif Mukkhtar]

Can some one please help
Q9
http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s06_qp_1.pdf
Q37,40
http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s07_qp_1.pdf

 

[gary221]

Can some one please help
Q9
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s06_qp_1.pdf

9) when the mass is at the lowest point, its kinetic energy = 0.
hence its velocity is also = 0 m/s
that means, either B or D.
since the first part of the graph shows the "UPWARD" velocity of the mass, hence the ans is D
Hope u gt it!
All credit to Nibz

 

[zackle09]

http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s09_qp_1.pdf

in questions like the one in number 6...how are you supposed to know when to convert voltage to V or leave it as mV? sometimes they do it and sometimes they dont :/

 

[samir2012]

can anyone please show me the scanned answer for Q.1 of M/J' 12 variant 52?? URGENT!!!

 

[gary221]

Can some one please help

Q37,40
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s07_qp_1.pdf

40) It is the q/m ratio that is important, and this has the lowest value for the lithium nucleus. ← given in the examiner report.
So, u have to calculate the charge to mass ratio, whichever is the lowest will have the least acceleration.
q/m ratio of hydrogen = 1/1 = 1
q/m ratio of helium = 2/4 = 0.5
q/m ratio of lithium = 3/7 = 0.42
q/m ratio of beryllium = 4/9 = 0.44

lowest ratio is that of lithium, hence that will have the lowest acceleration.

37) Not sure about this, but i think that since the volume of the two pieces are equal, their resistances will also be equal.

Hope u gt it!
All credit to Nibz

 

[daredevil]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s09_qp_1.pdf

in questions like the one in number 6...how are you supposed to know when to convert voltage to V or leave it as mV? sometimes they do it and sometimes they dont :/

ummm r u sure it's the ryt link bcz q6 is not a voltage question in this paper

 

[zackle09]

ummm r u sure it's the ryt link bcz q6 is not a voltage question in this paper

LOL sorry i meant question 4

 

[syed1995]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s09_qp_1.pdf

in questions like the one in number 6...how are you supposed to know when to convert voltage to V or leave it as mV? sometimes they do it and sometimes they dont :/

What's the formula for Power? P=IV

you need to work in the same units.. so convert the V reading from mV to V (THAT'S the best thing to do in every question).

they should be both in their standard form which will give you power in terms of standard watts... (As the final answer is in watts)

SO ALWAYS CONVERT IT INTO STANDARD UNITS before doing the calculations..

1200mV = 1.2V
0.48A

P=IV
P=1.2*0.48
P=0.576

so answer is B.

 

[zackle09]

What's the formula for Power? P=IV

you need to work in the same units.. so convert the V reading from mV to V (THAT'S the best thing to do in every question).

they should be both in their standard form which will give you power in terms of standard watts... (As the final answer is in watts)

SO ALWAYS CONVERT IT INTO STANDARD UNITS before doing the calculations..

1200mV = 1.2V
0.48A

P=IV
P=1.2*0.48
P=0.576

so answer is B.

Okayy got it! thanks alotttt

 

[zackle09]

can someone help me with these questions?

http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s09_qp_1.pdf

10 20 25 and 29

 

[gary221]

can someone help me with these questions?

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s09_qp_1.pdf

10 20 25 and 29

10) conservation of momentum = momentum b4 and after are always equal.
So, since b4 the split, the momentum = 0...hence after the split the total momentum shud also =0 ----> the momentum if both the particles shud be the same (as they moce in opp direction,the momenta cancel each other out).
So, since one particle has mass = 2m, the other will have velocity = 2v.
So, the momentum wud be 2mv for both.

Now, for K.E. we square the velocity.
So, particle 1, mass = m. velocity = 2v. so K.E. = 1/2 * m * (2v)^2 ------> 2mv^2
particle 2, mass = 2m. velocity = v. so K.E. = 1/2 * 2m * v^2 -----> mv^2

ratio = 2: 1

Hope i helped.
All credit to Nibz

 

[papersxtreme]

june 2012/ 11 mcq 12

june 2012/12 mcq 13

Help. Please

 

[gary221]

can someone help me with these questions?

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s09_qp_1.pdf

10 20 25 and 29

25) formula for diffraction grating ----> nλ = dsinΘ
check this out ---->http://www.s-cool.co.uk/a-level/physics/diffraction/revise-it/diffraction-from-a-diffraction-grating
so d = 1/N, N = no of lines

So, the formula = nλ = sinΘ/N
gradient = sinΘ/λ
So, rearranging the abv formula, sinΘ/λ = Nn
Ans = C

Hope i helped.
All credit to Nibz

 

[messi10]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w10_qp_53.pdf

Oct/nov 2010 p53. Q no 1

Can anyone please provide assistance in Q 1.
How the diagram and little about procedure..

In mark scheme, its a bit confusing for me.

I'll be grateful.
Regards!

 

[gary221]

june 2012/ 11 mcq 12

june 2012/12 mcq 13

Help. Please

link?

 

[Tkp]

hey in n07 to measure pressure we are using pressure gauge. it's saying not allow pressure meter or barometer. so in calculating pressure do we always use pressure gauge or sometimes pressure meter or barometer can be used. and in mark scheme there is a pt written difficulty in measuring amplitudes at small pressures. Use a large incident source. So i wrote that use high values of p so that a could be measures easily. So can u explain this mark scheme point. And another point that the window should be perpendicular to source. Should we write this point whenever something is being transmitted through a substance? And what is the purpose of the pt. these are a lot of questions sorry but plzz help

Didnt understand what u said?give me a ques similar like this