Physics: Post your doubts here!

[sellinimmie]

HEY everyone please very important for the practical, the last 2 questions always state 4 sources of errors and improvements, please can someone help me with this

Answers are in the Mark Schemes here: http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/

Here are some common answers..
Limitations:
- two results not enough
- measurement of radius/distance/etc. not accurate
- difficult to stop stopwatch at correct moment
Improvements:
- take more readings and plot a graph
- use vernier caliper/travelling microscope
- record using video camera, play in slow motion & use a timer

 

[sellinimmie]

Someone please answer: Is there a proper angle (from the vertical axis) for the starting position of a pendulum when finding its oscillation's time period? Should the bob be raised at a small angle so it would move slow?

 

[danyaljamil]

Someone please answer: Is there a proper angle (from the vertical axis) for the starting position of a pendulum when finding its oscillation's time period? Should the bob be raised at a small angle so it would move slow?

no unless mentioned just displace the bob enough so that you can easily track its oscillations and measure its time period

 

[sellinimmie]

no unless mentioned just displace the bob enough so that you can easily track its oscillations and measure its time period

ok. thanks

 

[Namit Verma]

http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s08_qp_4.pdf Can anyone explain q6.a ? And for 5.b what do they expect us to draw? should we just draw 2 capacitors in series connected in parallel to another 2 capacitors in series ( total 4 capacitors ).. Cause that makes the whole capacitance = 4500 µF

 

[1357911]

http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s08_qp_4.pdf Can anyone explain q6.a ? And for 5.b what do they expect us to draw? should we just draw 2 capacitors in series connected in parallel to another 2 capacitors in series ( total 4 capacitors ).. Cause that makes the whole capacitance = 4500 µF

Q-5b. yes its 2 in series with one in parallel.

 

[IR Germany]

help please, question 7 http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s07_qp_1.pdf

 

[Namit Verma]

help please, question 7 http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s07_qp_1.pdf

According to the diagram, v = u + X. For the motion of a particle in a straight line with uniform acceleration, v=u+at. So X=at . Answer C

 

[Namit Verma]

Q-5b. yes its 2 in series with one in parallel.

Okk and the others?

 

[1357911]

Okk and the others?

Im sorry. We havent yet started those chapters.

 

[IR Germany]

question 14 please http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s08_qp_1.pdf

 

[IR Germany]

question 14 please http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s08_qp_1.pdf

 

[IR Germany]

According to the diagram, v = u + X. For the motion of a particle in a straight line with uniform acceleration, v=u+at. So X=at . Answer C

thank you but what does it means with the force is not the same direction as the initial velocity?

 

[JessieN.]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w12_qp_21.pdf

4（b)(iii) plsss help!!!

nλ = 2 × 625 is a constant (1250) C1 n = 1 → λ = 1250 outside visible
n = 3 → λ = 417 in visible
n = 4 → λ = 312.5 outside visible
λ=420nm

Really don't understand what the answer says, can someone please explain for me?? Thanks!!!

 

[danyaljamil]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w12_qp_21.pdf

4（b)(iii) plsss help!!!

nλ = 2 × 625 is a constant (1250) C1 n = 1 → λ = 1250 outside visible
n = 3 → λ = 417 in visible
n = 4 → λ = 312.5 outside visible
λ=420nm

Really don't understand what the answer says, can someone please explain for me?? Thanks!!!

strange question okay here goes remember that maxima and minima are formed at alternating points for e.g if n=1 is maxima then n=3,5,7 can only be used for the n values the angle and grating are the same so dsinO is a constant and nλ should be equal to it so just put in the n values in that and find the corresponding wavelenght for this question n=3 gives 417nm so 420nm to 2 s.f hope this helped

 

[kalpaveen]

does any1 have have a gud set of section B shoetnotes??

 

[hellangel1]

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w12_qp_43.pdf
Please can anyone tell how to make the graphs for Q5 part b and c-ii

 

[Seenat Snt]

can anyone please help with O/N 2008 paper 1 question 11????

 

[Khadija.95]

http://papers.xtremepapers.com/CIE/...A and AS Level/Physics (9702)/9702_w03_ms.pdf
Guys, in Q1 part (c), the Marking Scheme uses formula s=ut+1/2at^2
Why can't we use 2as= v^2 x u^2 ?

 

[salvatore]

can anyone please help with O/N 2008 paper 1 question 11????

The 2kg mass is pulling the 8kg mass with a force of mg = 2 x 9.81 = 19.62N
Hence the force pulling the 8kg mass is 19.62N

But due to friction, the accelerating force would be:
19.62N - 6N
= 13.62N

From Newton's second law of motion;
f = ma
a = f/m
a = 13.62 / (8+2)kg <------ dont forget to add the masses

a = 1.362 m/s^2

Answer = A

Hope that helped

 

[salvatore]

http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s06_qp_4.pdf

Could someone please help me with the whole of qn 8 of this paper? I'll really appreciate it

Thanks