Answer
(a) zero
(b) I
Work Step by Step
(a) We know that when a positive charge is moved from one equipotential location to another equipotential location, there is no work done on the positive charge as there is no change in potential. Thus, the work done is zero.
(b) The best explanation is option (I) -- that is, the electric field is perpendicular to an equipotential, therefore the work done in moving along an equipotential is zero.
