ALL CIE PHYSICS DOUBTS HERE !!!

[Rvel Zahid]

hi everyone, hope your preparation is going well. best of luck to all for exams.
some past paper problems:-
http://www.xtremepapers.com/papers/CIE/Cambridge%20International%20A%20and%20AS%20Level/Physics%20(9702)/9702_w07_qp_1.pdf
 23 , 24 and 25

http://www.xtremepapers.com/papers/CIE/Cambridge%20International%20A%20and%20AS%20Level/Physics%20(9702)/9702_w06_qp_1.pdf
q. 27

[Physics09]

Q 24: Wavelength is directly proportional to fringe separation . Fringe separation or the distance between two successive dark/bright fringes or according to this question, 'line', increases with a longer wavelength. So answer is D.
Fringe separation is indirectly proportional to distance b/w the slits.
and directly proportional to the distance b/w the slits and the screen.
Hope it helps!

[Physics09]

Thank you! Yes anybody please answer the rest of the questions!

[Most UniQue™]

    23. frequency=8/50=0.16hz
    Maximum speed of P=2 x 3.14 x 2 x 0.16=2.01
    Max K.E.=1/2 x 0.002 x (2.01)^2=4.0mJ
    B is answer.
    25. d sin (theta)=nlamda
    Equation 1: d sin 45=3l Equation 2: d sin(90)=nl
    Divide Equation 1 by 2: sin 45=3/n
    so n=4.2426..... and you have to round down to the nearest integer which is 4.
    Answer is B.

[Rvel Zahid]

Thankyou so much muscle nerd and physics09!!


http://www.xtremepapers.com/papers/CIE/Cambridge%20International%20A%20and%20AS%20Level/Physics%20(9702)/9702_s09_qp_2.pdf

paper21 : Q.5

[LekhB]

Can anyone help with that?
Design an experiment to investigate how the intensity of light from a source varies with time.

[Rvel Zahid]

Can anyone help with that?
Design an experiment to investigate how the intensity of light from a source varies with time.

hey check out this thread! this might help you.
http://www.physicsforums.com/showthread.php?t=166961

[Ghost Of Highbury]

Can anyone throw some light on the number of significant figures or decimal places we should round off the final answer to?
In Physics/Chemistry paper 4s, paper 5s and Math P3?

For example, I recently solved a Communication system sums and got the answer as 5.3/12 *1000 = 441.6666..7 m

Look what the markscheme says

 "length = 5.3 / 12 km
= 440 m"

I could've rounded it off to 3 s.f and made it 442m. Why does it say 440m then? How do you go about this? Will the deduct marks if the answer
isn't rounded off to the appropriate number of s.f or d.p?

Thanks

[SkyPilotage]

Can anyone throw some light on the number of significant figures or decimal places we should round off the final answer to?
In Physics/Chemistry paper 4s, paper 5s and Math P3?

For example, I recently solved a Communication system sums and got the answer as 5.3/12 *1000 = 441.6666..7 m

Look what the markscheme says

 "length = 5.3 / 12 km
= 440 m"

I could've rounded it off to 3 s.f and made it 442m. Why does it say 440m then? How do you go about this? Will the deduct marks if the answer
isn't rounded off to the appropriate number of s.f or d.p?

Thanks

I have the same problem too, I dont know if they will deduct marks, but nothing is written about it in the marking scheme or the examiner report.
Sometimes marking scheme says deduct 1 mark if its not 3 s.f.
But I think the reason it is 420 is because 5.3 and 12 are 2 s.f so the answer must be the least s.f of both of them. which is 2s.f = 420 m

[Ghost Of Highbury]

I have the same problem too, I dont know if they will deduct marks, but nothing is written about it in the marking scheme or the examiner report.
Sometimes marking scheme says deduct 1 mark if its not 3 s.f.
But I think the reason it is 420 is because 5.3 and 12 are 2 s.f so the answer must be the least s.f of both of them. which is 2s.f = 420 m

420m? 2s.f?

3 s.f no?

[SkyPilotage]

yes 420 m i.e 2 s.f since the information given in the question is 2 s.f...
Since , 3 s.f are not used in the question. Dont use it, but Im not sure if they will deduct marks or not.

[Naruto123]

http://www.xtremepapers.com/papers/CIE/Cambridge%20International%20A%20and%20AS%20Level/Physics%20%289702%29/9702_s05_qp_4.pdf
question 6b why is it 90 degrees
Can any1 summarize all the graphs for primary current voltage flux and secondary flux current voltage .

[Ghost Of Highbury]

Well, this isn't much of a summary but remember this.

The flux changes according to the current, so same shape.

But you know, the field strength = -potentiala gradient of the flux.

Or E = d(flux)/dt (faraday's law)

so if the shape of the flux against time is like a sine curve. d/dt (sin t) = cos t.
So the E will be like a cos t starting from (0,1)

And as you know the phase difference b/w sine and cos curve is 90 degrees.

[Ghost Of Highbury]

Summer 2007, question 10a)

At t=0, will the signal be 0 or 2?

question 7b)

Why does the damping decrease when the resistance increases?

[SkyPilotage]

Summer 2007, question 10a)

At t=0, will the signal be 0 or 2?

question 7b)

Why does the damping decrease when the resistance increases?

How are you studying for paper 5?
Are you studying experiments? cz I dont know where to find them :S
Didnt go into school labs .. soo If you could share some resources I would appreciate it!