One metallic sphere A is given a positive charge whereas another identical metallic sphere B of the exact same mass as of A is given an equal amount of negative charge. Then:

(1) mass of A and mass of B are the same.

(2) mass of A is more.

(3) mass of B is less.

(4) mass of B is more.

The charge on 500 cc of water due to protons will be:

1. 6.0 × 10²⁷ C
2. 2.67 × 10⁷ C
3. 6 × 10²³ C
4. 1.67 × 10²³ C

A neutral bubble made of soap solution has radius R. If some negative charge is given which gets distributed uniformly on the surface of the bubble, the radius of the bubble becomes R' then

1.  R' > R

2.  R' = R

3.  R' < R

4.  R' = 0.5 R

A particle of mass m has a charge $q_0$ when it is at rest. When the particle moves with speed v, the charge on the particle will become (c is the velocity of light in vacuum)

1.  $\frac{q_{0}v}{c}$

2.  $\frac{q_{0}c}{v}$

3.  $\frac{q_0}{\sqrt{1-\frac{v^2}{c^2}}}$

4.  $q_0$