Question

Describe schematically the equipotential surfaces corresponding to 

(a) a constant electric field in the z-direction, 

(b) a field that uniformly increases in magnitude but remains in a constant (say, z) direction, 

(c) a single positive charge at the origin, and 

(d) a uniform grid consisting of long equally spaced parallel charged wires in a plane.

Answer 1

(a) Equidistant planes parallel to the x-y plane are the equipotential surfaces. 

(b) Planes parallel to the x-y plane are the equipotential surfaces with the exception that when the planes get closer, the field increases.

(c) Concentric spheres centered at the origin are equipotential surfaces.

(d) A periodically varying shape near the given grid is the equipotential surface. This shape gradually reaches the shape of planes parallel to the grid at a larger distance.