Question

The electric field strength at a far-off point P due to a point charge, +q located at the origin O is 100 milliVolt/meter. The point charge is now enclosed by a perfectly conducting hollow metal sphere with its centre and the origin O. The electric field strength at the point, P is

(a) Remains unchanged in its magnitude and direction

(b) Remains unchanged in its magnitude but reverse in direction

(c) Would be that due to a dipole formed by the charge, +q, at O and -q induced

(d) Would be zero

This question was addressed to me in an interview for internship.

Asked question is from Advanced and Tricky Questions topic in section Advanced and Tricky Questions of Electromagnetic Theory

Answer 1

Correct choice is (d) Would be zero

The best explanation: According to Gauss Law, the total displacement or electric flux through any closed surface surrounding charges is equal to the amount of charge enclosed. The total enclosed charge is -q + q = 0. Thus the flux and electric field strength will be zero.