Physics Past Questions and Answers

The correct expression for the potential at a point distance r from a charge q in an electric field is

A <table class='tbn'><tbody><tr>_q<sup style='font-size: smaller;'>2</sup> </td></tr><tr><td> 4Ï€Îµ<sub style='font-size: smaller;'>o</sub>r<sup style='font-size: smaller;'>2</sup> </td></tr></tbody></table>
B <table class='tbn'><tbody><tr>_q<sup style='font-size: smaller;'>2</sup> </td></tr><tr><td> 4πε<sub style='font-size: smaller;'>o</sub>r </td></tr></tbody></table>
C <table class='tbn'><tbody><tr>_q </td></tr><tr><td> 4Ï€Îµ<sub style='font-size: smaller;'>o</sub>r<sup style='font-size: smaller;'>2</sup> </td></tr></tbody></table>
D <table class='tbn'><tbody><tr>_q </td></tr><tr><td> 4Ï€Îµ<sub style='font-size: smaller;'>o</sub>r </td></tr></tbody></table>

Question 1617:

An image in a convex lens is upright and magnified 3 times. If the focal length of the lens is 15 cm, what is the object distance?

A 10 cm
B 25 cm
C 16 cm
D 14 cm

Question 1618:

A length of wire has a frequency of 255Hz when stretched by a force of b225N. If the fore increased to 324N, what is the new frequency of vibration

A 306 Hz
B 512 Hz
C 488 Hz
D 356 Hz

Question 1619:

In the circuit above, three resistors, 2Î©, 4Î© and 12Î© are connected in parallel and a 12V battery is connected across the combination. The current flowing through the 12Î© resistors is

A 14.4 A
B 1.0 A
C 3.2 A
D 9.6 A

Question 1620:

If the volume of a gas increases steadily as the temperature decreases at constant pressure, the gas obeys

A Graham's Law
B Boyle's Law
C Pressure law
D Charles Law
E No Correct Option