Case 1: A point charge Q is placed a distance a from the origin on the +y axis.

Case 2: A total charge Q is spread uniformly over a ring of radius a that lies in the y-z plane.

Consider a point a distance x along the x-axis. In which case is the magnitude of the electric field greater?

1. Case 1
2. Case 2
3. neither, they're equal

In which case is the magnitude of the electric potential greater?

1. Case 1
2. Case 2
3. neither, they're equal

Potential is a scalar, so all that matters for potential is that in both cases the charge is the same distance (x² + a²)^1/2 from the point. In both cases, then, the potential is given by:

V(x) = kQ/(x² + a²)^1/2