Question

A and B are two conducting concentric spherical shells. A is given a charge Q while B is uncharged. If now B is earthed as shown in figure. Then:

• A. The charge appearing on inner surface of B is -Q.
• B. The field inside and outside A is zero.
• C. The field between A and B is not zero.
• D. The charge appearing on outer surface of B is zero.

Answer 1

Answer: (A), (C), (D)

The correct options are
A The charge appearing on inner surface of B is -Q.
C The field between A and B is not zero.
D The charge appearing on outer surface of B is zero.

Initial condition:
Charger on outer surface of A = Q
Charger on inner surface of B = -Q
Charger on outer surface of B = Q

After earthing:
Charger on outer surface of A = Q
Charger on inner surface of B = -Q
Charger on outer surface of B = 0 $[Since{V}_B=\frac{K\left(Q\right)}{R}+\frac{K(-Q)}{R}=0]$