Question
Define an equipotential surface. Draw equipotential surfaces:
(i) in the case of a single point charge and in a constant electric field in Z-direction.
(ii) Why the equipotential surfaces about a single charge are not equidistant?
(iii) Can electric field exist tangential to an equipotential surface? Give reason.
Solution
i) Equipotential surface for a single point charge is:
ii) The equipotential surface about a single charge is not equidistant because V is inversely proportional to r.
Also, the equipotential surfaces about a single charge are not equidistant because electric field due to a single charge is not constant.
iii) Electric field cannot exist tangential to an equipotential surface because if the field lines are tangential, work will be done in moving a charge on the surface, which is against the theory of equipotential surface.
