Question

A charge q is distributed uniformly on the surface of a sphere of radius R . It is covered by a concentric hollow conducting sphere of radius 2R . Find the charges on the outer surface of hollow sphere if it is earthed

Answer 1

{Check attachment} Drawing a closed gaussion surface through the material of the hollow sphere, the total charge encloses by this gaussion surface should be zero, so

The charge on the inner surface should be -q

Let q1 be the charge on the outer surface of sphere

Since outer sphere is earthed, potential on it is zero. So we have

1 / 4π∈₀ [ q/2R - q/2R + q1/2R ] = 0

1 / 4π∈₀ [ q1/2R ] = 0

this gives, q1 = 0

Therefore, the charge on the outer surface of sphere is zero.

Answer 2

Answer:

0

Explanation:

since the outer sphere is earthed all the excess charge will flow back to earth or the charge deficit will be compensated by the earth. Hence charge on the outer surface becomes zero