Two large equipotential surfaces are flat and parallel, and they are separated by a relatively small distance compared to their size. One surface is at 25 V and the other is at 33 V. The surfaces are 1.25 cm apart. Assuming the electric field is uniform between the surfaces, what is the direction of the electric field midway between them?

Question

Quizplus · Accepted Answer

The electric field always points from the higher potential to the lower potential. Since the higher potential is on the 33 V surface, the electric field will point toward the 25 V surface. Also, since the surfaces are parallel and the electric field is uniform, the electric field must be perpendicular to the surfaces. Therefore, the electric field is perpendicular to the surfaces and points toward the 25 V surface, which is choice C.

Two Large Equipotential Surfaces Are Flat and Parallel, and They