Physics: Post your doubts here!

[Lyfroker]

http://freeexampapers.com/A-Level/Physics/CIE/2002-Nov/9702_w02_qp_4.pdf

Q#2(b) & Q#5

 

[The Chill Master]

View attachment 52575

Because Cell A is charging Cell B and whenever a cell is charging we add both the e.m.f's .

 

[Lyfroker]

http://freeexampapers.com/A-Level/Physics/CIE/2002-Jun/9702_s02_qp_4.pdf

Q#6(a)

 

[Zash Riyash]

http://freeexampapers.com/A-Level/Physics/CIE/2002-Jun/9702_s02_qp_4.pdf

Q#6(a)

You're giving A levels as well? Also, did you figure out that estimate question?

 

[TheJDOG]

http://freeexampapers.com/A-Level/Physics/CIE/2002-Jun/9702_s02_qp_4.pdf

Q#6(a)

According to lenz's law, emf tends to oppose the change causing it, so here, sketch will just have opposite peaks, and when current is constant, no emf on sketch, since no emf is induced when there is no change

 

[Boss201]

Number 1 part (b)

i don't understand how to draw this current vector diagram and unable to resolve. pls help

a vector diagram will be appreciated.

Thanks

 

[The Sarcastic Retard]

Number 1 part (b)

i don't understand how to draw this current vector diagram and unable to resolve. pls help

a vector diagram will be appreciated.

Thanks

This question can be solved using parallelogram rule.
https://www.xtremepapers.com/community/attachments/capture1-png.10278/
To find the resultant magnitude, there are two ways:
- you have a rule don't you? Use it to measure the relative length of the forces. Force magnitude ratio equals diagram length ratio. Use the ratio to calculate. This is the "unprofessional" way but it works.
- use purely mathematics to calculate the force. Resolve the two forces and you get for the 6N, x-component is 6 cos40, y-component 6 sin40. The 8N, x-component 8, y-component 0. So the resultant x-component = 8 + 6 cos40, y-component 6 sin40.
Resultant magnitude, using Pythagorean Theorem, is sqrt [(8 + 6 cos40)^2 + (6 sin40)^2].
Answer should be 13.2N

 

[nehaoscar]

http://freeexampapers.com/A-Level/Physics/CIE/2012-Jun/9702_s12_qp_23.pdf

Question 2 c
How exactly should the graph look like?
Can someone please draw it?

The attached file is how i thought it would (the lines are meant to be straight )
But the mark scheme says that the gradient of the negative is less steep or something so how should it look like?

 

[nehaoscar]

http://freeexampapers.com/A-Level/Physics/CIE/2012-Jun/9702_s12_qp_23.pdf

Question 4 part iv

Why is change is ke = work done - change in gpe ?

 

[ashcull14]

i used formula P=V^2/R and got the ratio 1.6....while in MS P=VI is used nd the option of V^2/R is given but the ans is 0.6 which is obtained only by P=VI....Where am i wrong???

 

[ashcull14]

 

[The Sarcastic Retard]

http://freeexampapers.com/A-Level/Physics/CIE/2012-Jun/9702_s12_qp_23.pdf

Question 2 c
How exactly should the graph look like?
Can someone please draw it?

The attached file is how i thought it would (the lines are meant to be straight )
But the mark scheme says that the gradient of the negative is less steep or something so how should it look like?

Refer this : https://www.xtremepapers.com/commun...st-your-doubts-here.9860/page-632#post-883149

 

[NIM]

Need help for question b ii but check if I'm right for i

 

[nehaoscar]

http://freeexampapers.com/A-Level/Physics/CIE/2011-Jun/9702_s11_qp_23.pdf

Question 6 part iv

Why is it a straight line through the middle :O how??? please explain!

 

[Zash Riyash]

http://freeexampapers.com/A-Level/Physics/CIE/2011-Jun/9702_s11_qp_23.pdf

Question 6 part iv

Why is it a straight line through the middle :O how??? please explain!

That line only depicts the zero displacement, from where you measure the amplitude or trough!

 

[eliyeap]

Question 6 part iv

Why is it a straight line through the middle :O how??? please explain![/QUOTE]
http://physics-ref.blogspot.com/2014/11/physics-9702-doubts-help-page-7.html. They explain in detail here. Hope you see the light!

 

[Boss201]

question 1(b)

the diameter of the wire is found to be 0.50 + or - 0.02mm.Calculate % uncertainty in
(1) the diameter
(2)the area of cross_section of the wire

 

[The Sarcastic Retard]

question 1(b)

the diameter of the wire is found to be 0.50 + or - 0.02mm.Calculate % uncertainty in
(1) the diameter
(2)the area of cross_section of the wire

1) 0.02/0.5 * 100 = 4%
2) cross... area = Pi * d^2 / 4 so % UC is 2*UC of d = 8%

 

[Jennifer4678]

Hey.. The equation states r(^2) but they didn't include it in the calculation.... that always seems to be the case in other problems as well. Can someone please explain this to me? Thanks!

 

[nehaoscar]

Hey.. The equation states r(^2) but they didn't include it in the calculation.... that always seems to be the case in other problems as well. Can someone please explain this to me? Thanks!

Which book is that? Is it like a revision guide or work book? and if so is it helpful?
Please could you give me the name and cover of the book?