Question

A conductor lies in an electric field. If a charge moves on the surface, what is the work done on the charge?

• A. Depends on the force and distance.
• B. Zero
• C. Not enough information
• D. A charge cannot move on a conductor.

Answer 1

The correct option is B Zero

The surface of a conductor is an equipotential surface (remember that electric field lines fall perpendicular to the surface of conductor and hence on moving a charge over the surface of a conductor, no work is done), the work done in moving a charge on an equipotential is zero. Recall that work done by an external agent is given by q $(V_f-V_i)$. Here $(V_f=V_i)$ as the surface is equipotential and thus work done is zero.