Question

A spherical conducting shell has charge Q. A point charge q is placed at the center of the cavity. The charge on the inner surface of the shell and the charge on the outer surface of the shell, respectively, are:
a. -q, 0
b. q, Q - q
c. 0, Q
d. -q, Q + q
e. Q, 0

Answer 1

Answer:d

Explanation:

From Gauss law Electric field inside a surface is directly proportional to the charge enclosed in it.

Electric field inside a spherical shell is zero and hence there is no charge inside the spherical shell because q charge induces a -q charge on inside surface of spherical shell.

and to counter it there is q charge on the surface. So total charge outside the surface is Q+q