Physics: Post your doubts here!

[Yousuf Ykr]

can anyone solve paper 12 of Oct/Nov of 2012? i gat only problems wid 14, 18, 30 and 37

 

[danyaljamil]

Guys, I need some help in this paper:
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w08_qp_4.pdf
Q 1 b)i)

you need to know for this question that the earth is not exactly spherical but is an ellipsoid and hence its radius varies and is greater at the equator than at the poles hence the weight of any object and the normal reaction at the equator is different than at the poles
hope this helped

 

[adibshamsuddin]

9702_w09_qp_22.pdf . I need help with this question, 5 (b) . Why the phase difference is 180 degree. Please, little help would be very appreciated.

 

[6Astarstudent]

9702_w09_qp_22.pdf . I need help with this question, 5 (b) . Why the phase difference is 180 degree. Please, little help would be very appreciated.

judging from the fact that you asnwered part A, you know its a sinusoidal stationary wave and X has same amplitude as Y. But at any instant they are moving in opposite direction so they're 180 degrees out of phase.

 

[adibshamsuddin]

9702_w05_qp_2.pdf Can anyone help me with 7 (b) (ii) 1. Why is the pd 2.70? galvanometer reading would be zero not voltmeter?

 

[6Astarstudent]

9702_w05_qp_2.pdf Can anyone help me with 7 (b) (ii) 1. Why is the pd 2.70? galvanometer reading would be zero not voltmeter?

pd is 2.7 because V = V(total) x resistance (thermistor) / resistance (total) = 4.5 x 1800 / (1200+1800) = 2.7 this is a potential divider.
and it doesnt matter if its a galvanometer or voltmeter or not, because the potential is equal so potential difference is 0.

 

[M.Saud Lakhany]

q7 guys!

 

[6Astarstudent]

View attachment 32315
q7 guys!

answer is E, because parallel circuits. so V across the 5ohm 3ohm line is 3V.
and I = V/R which is I = 3/(5+3) = 3/8

 

[adibshamsuddin]

9702_s06_qp_2.pdf someone please help me with question 7 c. Clueless :/

 

[AmeeraKhan]

Hey, I have my physics practical resit tomorrow... And just wasn't sure about which setting you're supposed to have the voltmeter on (i.e 2, 20, 200?) and the ammeter aswell.... Can someone please explain which setting to have and in what circumstances? Thanks.

 

[M.Saud Lakhany]

part (iii) and (iv) guys! It would really be helpful if you explain the concept of open and closed switches too

 

[M.Saud Lakhany]

They

Hey, I have my physics practical resit tomorrow... And just wasn't sure about which setting you're supposed to have the voltmeter on (i.e 2, 20, 200?) and the ammeter aswell.... Can someone please explain which setting to have and in what circumstances? Thanks.

The invigilators set the ammeters for you!
Any idea whats coming in tomorrows practical? Ive it too!

 

[AmeeraKhan]

They

The invigilators set the ammeters for you!
Any idea whats coming in tomorrows practical? Ive it too!

Oh ok then... Well in w11 n w12 they had electricity so it may not come this time... (It could still)... Just know how to plot graphs properly and learn all the limitations and improvements for mark schemes...

 

[M.Saud Lakhany]

Oh ok then... Well in w11 n w12 they had electricity so it may not come this time... (It could still)... Just know how to plot graphs properly and learn all the limitations and improvements for mark schemes...

Okay! And btw has waves ever come in practical?

 

[AmeeraKhan]

Okay! And btw has waves ever come in practical?

Nope..never... It will always be mechanics/thermal physics or electricity

 

[M.Saud Lakhany]

In part d why do we have to make the table of d im mm according to marking scheme though the ans we got in c(ii) is in metre?

 

[1357911]

Okay! And btw has waves ever come in practical?

No.

 

[Princess Raven]

May anyone please explain to me why the answer to question 7 (in the paper linked) is C?

http://papers.xtremepapers.com/CIE/Cambridge%20International%20A%20and%20AS%20Level/Physics%20(9702)/9702_s07_qp_1.pdf
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)
papers.xtremepapers.com

 

[danyaljamil]

in the dia

May anyone please explain to me why the answer to question 7 (in the paper linked) is C?

http://papers.xtremepapers.com/CIE/Cambridge%20International%20A%20and%20AS%20Level/Physics%20(9702)/9702_s07_qp_1.pdf
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)
papers.xtremepapers.com

in the diagram V the final velocity is shown as the resultant of the two vectors that are added together and one of them is U inital velocity and the other is X so X must be ut in the diagram as v=u+at

 

[6Astarstudent]

In part d why do we have to make the table of d im mm according to marking scheme though the ans we got in c(ii) is in metre?View attachment 32332 View attachment 32334

nearest mm doesn't mean the table has to be in mm. eg. 0.582m is to the neariest mm because 0.582m =582mm
it has to be in nearest mm because thats the smallest scale the metre rule reads to.