Question

The work done in moving 500 µC charge between two points on equipotential surface is
(a) zero
(b) finite positive
(c) finite negative
(d) infinite

Answer 1

An $\mathbf{equipotential}$ surface is the locus of all points which have the same electrostatic potential due to a charge distribution.
As you know, Workdone in electric field = q∆V
But in case of $\mathbf{equipotential}$ surface ∆V = 0 , because potential is same at every point on surface .
∴ Workdone = 0
e.g., The Workdone in moving a charge along an $\mathbf{equipotential}$ surface is always zero.

Hence, option (a) is correct