Physics: Post your doubts here!

[Mishaa]

please help
http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_w08_qp_1.pdf Q32 B
http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w10_qp_12.pdf Q7 D Q13 D Q25 D Q31 A
http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w12_qp_11.pdf Q23 A

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_s12_qp_11.pdf Q12 A
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w09_qp_11.pdf Q12 B

1. Take the 7 wires to be parallel to each other, so 1/R=6(1/10)+1/100. Answer is 1. 63.

 

[Mishaa]

please help
http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_w08_qp_1.pdf Q32 B
http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w10_qp_12.pdf Q7 D Q13 D Q25 D Q31 A
http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w12_qp_11.pdf Q23 A

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_s12_qp_11.pdf Q12 A
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w09_qp_11.pdf Q12 B

2. Q7 Acceleration upwards is always -9.81 and downwards 9.81. As upward motion is positive, + multiplied ny - gives you -9.81. Vice versa with downward motion. - multiplied with +9.81. The magnitude stays the same as long as air resistance is neglected, and the sign depends on which direction you take as positive.
Q13 Once the cube is fully immersed, no change in the reading should be seen. The reading corresponds to the WEIGHT - UPTHRUST, not the upthrust. And the pressure/force on vertical sides is not at all accountable/considerable, it's always the pressure on the bottom and top. Thus, the last is the correct option.

 

[mushoo]

down the column in question no 2, the sig fig shud remain same or the decimal place??
Rep asap.. please..

 

[Soldier313]

Jazakelee Allah alf khair

wa iyyakum.

 

[mushoo]

wa iyyakum.

Can u tel me tht
down the column in question no 2, the sig fig shud remain same or the decimal place??
Rep asap.. please..

 

[Soldier313]

Can u tel me tht
down the column in question no 2, the sig fig shud remain same or the decimal place??
Rep asap.. please..

as far as i know it's significant figures.

 

[Mishaa]

please help
http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_w08_qp_1.pdf Q32 B
http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w10_qp_12.pdf Q7 D Q13 D Q25 D Q31 A
http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w12_qp_11.pdf Q23 A

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_s12_qp_11.pdf Q12 A
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w09_qp_11.pdf Q12 B

Q25) Drawing the waveforms, l=1/4wavelength in X and l=1/2 wavelength in Y. As the speed of sound is constant, the ratios of the frequencies should be reciprocal to the ratio of wavelengths, that would be frequency of X:Y = 1:2. So frequency of Y is double of the frequency of X.
Q31) Conduction wires conduct due to mobile electrons, so C and D are incorrect. The movement of electrons random, so B is eliminated. A is correct.

3. Q23) I'm not entirely sure of this but the extension is denoted by W/k. Now P and Q have identical spring constants so total extenion = 2. Now PQ and R are taken in series so product over sum gives us the answer.

4. Q12) SOMEONE PLEASE SOLVE THIS FOR ME TOO.

5. Q12) R1 and R2 both act against the weight of the frame so their magnitude would be equal. T1 has a greater horizontal component than T2, the vertical one is in the same line of force as the weight and R for both and is not considered, so wire T1 is more tensed upp. More like how picture frames fall when you suspend them with too short a wire and they snap. Real life scenarios.

And I had a powercut scheduled in the middle so the 3 seperate posts. Sorry.

 

[Farru]

as far as i know it's significant figures.

okk.
my sir told me its decimal place, whereas mark scheme also show that sig fig shud remain same thru out the column.. :/
Thanks btw.JazakAllah khair!

 

[TaffsAsLevel]

u need to MULTIPLY THE PERCENTAGE UNCERTINITY OF L BY 2

How come, then it wil be +- 0.8 for all then? What about this?

Let's assume l is 10.2 (+- 0.4). When l is squared, we square the two extreme points and subtract them to get uncertainty in the l squared value.
10.2^2 = 104.04 and uncertainty = (10.2+0.4)^2 - (10.2-0.4)^2
= 10.6^2 - 9.8^2
= 112.36 - 96.04 = 16.32
So, we have 104.04 (+- 16.32).
Hope you get it.

 

[TaffsAsLevel]

u need to MULTIPLY THE PERCENTAGE UNCERTINITY OF L BY 2

I think that only applies to a given formula?

 

[MKh@lid]

http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_w08_qp_5.pdf
Need help in Q2, (e) i don't get how to find the uncertainty. Help would be appreciated.

 

[TaffsAsLevel]

Aoa wr wb
Can someone please upload a diagram for question 1 of this paper?

http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_w07_qp_5.pdf
http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_w07_ms_5.pdf

Thank you so much!

A loudspeaker incident and the sound received by a microphone or source detector. We put the detector as close to the glass to avoid reflection of sound and the detector behaves in such a way we want to know the details about the sound wave at the glass window, my thought though, I am doing it right now btw, what about the second question where they ask to draw best and worst fit line I don't get it

 

[TaffsAsLevel]

View attachment 27818

Good one, and to add the density doesn't make much sense because of their units, but adding mass or volume does make sense

 

[Soldier313]

okk.
my sir told me its decimal place, whereas mark scheme also show that sig fig shud remain same thru out the column.. :/
Thanks btw.JazakAllah khair!

owwh
you're welcome anytime. wa iyyakum.

 

[kiara15]

any1 tel me how to do quest 2 part c in http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s09_qp_5.pdf

 

[Soldier313]

A loudspeaker incident and the sound received by a microphone or source detector. We put the detector as close to the glass to avoid reflection of sound and the detector behaves in such a way we want to know the details about the sound wave at the glass window, my thought though, I am doing it right now btw, what about the second question where they ask to draw best and worst fit line I don't get it

yeah i don't get the way we have to insert the vacuum pump and the strain gauge :/
best fit line is the one that passes through all the plotted points except the anomalies
worst acceptable line is the one that passes through all the error bars (from the top of the first error bar to the bottom of the last error bar, or vice versa )

 

[samia khalid]

Re: Physics Help here! Stuck somewhere?? Ask here!
please can anyone post any solved paper5, q2 here ...i have problem with plotting the error bars. plzzzz help anyone
my prayers will always be for u....ia

 

[TaffsAsLevel]

yeah i don't get the way we have to insert the vacuum pump and the strain gauge :/
best fit line is the one that passes through all the plotted points except the anomalies
worst acceptable line is the one that passes through all the error bars (from the top of the first error bar to the bottom of the last error bar, or vice versa )

I don't think that is anything necessary to write because data collection is 5 marks, 1 for drawing, 1 for how to measure the value of the independent variable, 1 for dependent variable, and 2 marks to measure the other controlled variables. There is a vacuum pump somehow but I don't know how it works but it's enough to say you need the vacuum pump since all are one mark each. Simply mention it in bullet points as my revision guide suggested rather than how you actually do it by hand just say the apparatus for whichever it is.

 

[Soldier313]

I don't think that is anything necessary to write because data collection is 5 marks, 1 for drawing, 1 for how to measure the value of the independent variable, 1 for dependent variable, and 2 marks to measure the other controlled variables. There is a vacuum pump somehow but I don't know how it works but it's enough to say you need the vacuum pump since all are one mark each. Simply mention it in bullet points as my revision guide suggested rather than how you actually do it by hand just say the apparatus for whichever it is.

but i think it is necessary to include it in the diagram as far as i know :/
Thanx though!

 

[rehan751]

Guys my grade components in AS are AAC. Im hoping to get AA in A2 so can I get an A* with all As and a C in Paper 3?