Physics: Post your doubts here!

[leosco1995]

Yeah, I was moreorless going with the basic concept. I probably would have gotten it fully right if I read the elastic part of the question though.

 

[abcde]

http://www.xtremepapers.com/CIE/International A And AS Level/9702 - Physics/9702_w08_qp_1.pdf
I'm not very clear about MCQ 37. An explanation would help.

 

[Ahmed Ali Akbar]

Thanks...your explanations are really so very good...

 

[rz123]

http://www.xtremepapers.com/CIE/International A And AS Level/9702 - Physics/9702_w08_qp_1.pdf
I'm not very clear about MCQ 37. An explanation would help.

i think it should be A as in order to find the unknown potential difference on the wire XY we need to know the driver cell voltage. then we will be able to find pd per unit length on xy = XY/XT into E1

 

[Doctor Nemo]

http://www.xtremepapers.com/CIE/International A And AS Level/9702 - Physics/9702_w08_qp_1.pdf
I'm not very clear about MCQ 37. An explanation would help.

The galvanometer is a sensitive detector of current. When it reads zero there is no current through the loop that includes battery E2. This means that the voltage across XT is equal to the voltage of E2. Current can only flow between two points in a circuit if there is a voltage difference between the two points. Knowing this voltage and the length XT you can find the voltage per unit length.

It is not enough to know the voltage of E1 because it is in series with a resistor and some unknown amount of the voltage of E1 is lost across the resistor. Therefore the answer is B

 

[Ahmed Ali Akbar]

what is the effect of slit width (keeping the slit separation constant)on brightness of dark and bright fringes?.. in detail............

 

[OakMoon!]

what is the effect of slit width (keeping the slit separation constant)on brightness of dark and bright fringes?.. in detail............

Reducing the slit width decreases brightness of the fringes. The reason is that less light is let through the slits and the overall intensity reduces.

 

[Doctor Nemo]

what is the effect of slit width (keeping the slit separation constant)on brightness of dark and bright fringes?.. in detail............

If the width of the slits is increased then there is more light so bright fringes are brighter, with more light while dark areas remain the same. The fringe separation is the not affected by increasing the width of the slits. However the production of fringes depends on the diffraction of light by the slits.Increasing the width of the slits will decrease the amount of diffraction so that there will be fewer fringes. Decreasing the width of the fringes will have the opposite effects, less bright fringes but more fringes.

 

[abcde]

If the width of the slits is increased then there is more light so bright fringes are brighter, with more light while dark areas remain the same. The fringe separation is the not affected by increasing the width of the slits. However the production of fringes depends on the diffraction of light by the slits.Increasing the width of the slits will decrease the amount of diffraction so that there will be fewer fringes. Decreasing the width of the fringes will have the opposite effects, less bright fringes but more fringes.

If slit width is increased, fringe separation is reduced in accordance with the formula, x = (lambda)D/a, where x is the fringe separation and 'a' is the slit width. I agree with the rest. But since the effect on brightness is only asked, this point would be irrelevant.

 

[darknessinme]

If slit width is increased, fringe separation is reduced in accordance with the formula, x = (lambda)D/a, where x is the fringe separation and 'a' is the slit width. I agree with the rest. But since the effect on brightness is only asked, this point would be irrelevant.

'a' is the distance between the centres of the two slits. I don't think increasing slit width would have any effect on fringe separation.

 

[abcde]

'a' is the distance between the centres of the two slits. I don't think increasing slit width would have any effect on fringe separation.

'a' is the slit separation! Thank you for the correction.

 

[awais aslam]

A car travels one complete lap around a circular track at a constant speed of 120km/h.
Explain why values for the average speed and avg. velocity are different?

 

[rz123]

A car travels one complete lap around a circular track at a constant speed of 120km/h.
Explain why values for the average speed and avg. velocity are different?

speed is the rate of change of distance and velocity is rate of change of displacement hence involving direction! direction is always changing in the circular motion so you will get different velocity each time. whereas the speed remains same as no change in distance travelled in one lap

 

[MEGUSTA_xD]

speed is the rate of change of distance and velocity is rate of change of displacement hence involving direction! direction is always changing in the circular motion so you will get different velocity each time. whereas the speed remains same as no change in distance travelled in one lap

One more thing, velocity is vector quantity and speed is scalar.

 

[awais aslam]

Cambridge International AS Level and A Level Physics Teacher's Resource CD-ROM

 

[usmiunique]

How do u find out the errors in the table values which u calculate and the error in the gradient?
Also what is meant by the worst acceptable line and the error bars?

 

[rz123]

worksheet number 6 , Q.11 b part, need help.

 

[darknessinme]

Cambridge International AS Level and A Level Physics Teacher's Resource CD-ROM

Anybody have the answers for the End of Chapter Questions, and Exam Style Questions contained on this CD?

 

[rz123]

Anybody have the answers for the End of Chapter Questions, and Exam Style Questions contained on this CD?

i have dat cd worksheets nd ms which comes along with the chadha's Cambridge endorsed buk..let me know if u need it.

 

[Doctor Nemo]

worksheet number 6 , Q.11 b part, need help.

For b the average force is just the change in momentum over time.

So for the one on the right it is just (0.5k X 3.8 m/s)/0.25 =7.6N