Physics: Post your doubts here!

[Champ101]

Why does the ms say that there are less photons arriving per unit time?

oh can u tell me which year is it from?

 

[unique111]

Yeah that too! but more significant number means less uncertainty...so 3 sf is much reliable. im talking about paper 4 here.
For paper 5, you're right!

no no, I'm talking about ppr 2 and all. for eg: if you are required to find the force and you are given m=5.0kg and a=1.2 m s^-2 then wont force=ma=6.0 N and not 6.00N?

 

[Champ101]

no no, I'm talking about ppr 2 and all. for eg: if you are required to find the force and you are given m=5.0kg and a=1.2 m s^-2 then wont force=ma=6.0 N and not 6.00N?

Oh!! Yeah that absolutely correct. 6.0 N represents the perfect answer!

 

[forever_chocoholic]

In paper 5 and 3, how do we plot the points?
Do we enclose points in a circle or use a cross?

paper 3 practical? i prefer using a cross since u circle a point which is anomalous

 

[salvatore]

http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_w07_qp_4.pdf
Qn no. 5(b)ii.. Could someone please explain why 1cm^2 represents 156 microC?

 

[forever_chocoholic]

how can we prepare for physics practical paper 3?

 

[forever_chocoholic]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w07_qp_4.pdf
Qn no. 5(b)ii.. Could someone please explain why 1cm^2 represents 156 microC?

i am doing as level but i always find it useful to check the 'er', the examiners sometimes explain the questions.. do have a look
http://papers.xtremepapers.com/CIE/...A and AS Level/Physics (9702)/9702_w07_er.pdf

 

[forever_chocoholic]

could someone tell me whats a traveling microscope ? and where do we use it? since they keep mentioning about it in physics paper 3 (in improvements)in mark schemes

 

[A star]

any one some difficult questions pls. P4 :3

 

[JAVERIA INAM DANISH]

How to calculate ratio of alpha:beta?

 

[scouserlfc]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w07_qp_4.pdf
Qn no. 5(b)ii.. Could someone please explain why 1cm^2 represents 156 microC?

Just measure the area of the 1x1 square that u can form it comes out to be
1.25*0.125=0.15625mC = 156.25microC =156microC

This is just the area of one such box so multiply it with the no. of 1 x 1 squares below line to get answer !

 

[salvatore]

Just measure the area of the 1x1 square that u can form it comes out to be
1.25*0.125=0.15625mC = 156.25microC =156microC

This is just the area of one such box so multiply it with the no. of 1 x 1 squares below line to get answer !

How did you get 1.25 and 0.125? Sorry for bothering :/

 

[Namehere]

Anyone can explain Q9 (all) please?

 

[hope4thebest]

any one some difficult questions pls. P4 :3

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_s11_qp_41.pdf Q 5(c) (i)

 

[scouserlfc]

How did you get 1.25 and 0.125? Sorry for bothering :/

You really need the paper in its exact form and dimensions so that u can see the number of small blocks that are present in 1 cm so i actually enlarged the paper to the size we normally have and then used a scale to see what 1cm is. Dont worry in exam this will be easy.

 

[scouserlfc]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s11_qp_41.pdf Q 5(c) (i)

Its clockwise or bottom to top . As u know from part b that magnetic field direction is out of page use this and the Flemings Left Hand rule.

 

[Yousif Mukkhtar]

oh can u tell me which year is it from?

http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_s13_qp_43.pdf
May June 13 Q 7c) Paper 43

 

[Yousif Mukkhtar]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w13_qp_43.pdf
Can some one explain Q 7c)

 

[Malik777]

I'm assuming that you got the answers for the previous two parts.. for part (iii),
Intensity received back= (intensity reflected at the muscle-bone boundary)e^-(23 * 4.1 * 10^-2)

[ e^-(23 * 4.1 * 10^-2) = 0.39]


intensity of the wave incident on the boundary was 0.39I, as calculated in part (ii)
0.33 of this was reflected at the boundary.
So intensity reflected at the muscle-bone boundary= .39 * .33I

answer= .39 * .33I * .39 = .050I

I hope this helps

why you multiplied 0.39 twice ? :O

 

[forever_chocoholic]

anyone doing paper 3? i want to as if its fine to use crosses when plotting ur graph?