Equipotential Surfaces — Prelims Questions

Which of the following statements about equipotential surfaces is INCORRECT?

A positive charge is moved from point A to point B on an equipotential surface. The work done by the electric field is:

In a region where equipotential surfaces are closely spaced, what can be inferred about the electric field?

The equipotential surfaces for an isolated point charge are:

If the electric potential is constant throughout a given region of space, what can be concluded about the electric field in that region?

Two equipotential surfaces, $V_1 = 50,\text{V}$ and $V_2 = 30,\text{V}$, are separated by a perpendicular distance of $0.1,\text{m}$. What is the approximate magnitude of the electric field between them?