Question

Two point electric charges of unknown magnitude and sign are placed at some distance ${}^{\prime }{d}^{\prime }$ apart. The electric field intensity is zero at a point, not between the charges but on the line joining them.
Write two essential conditions for this to happen.

Answer 1

(i) The two charges must be of opposite kind.

(ii) The magnitude of two charges must be unequal. The charge closer to the point of observation should be of smaller magnitude.