The Equipotential Surfaces for Two Point Charges Are Shown in the Figure

Short Answer

The equipotential surfaces for two point charges are shown in the figure, with the value of potential marked on the line for each surface.
(a) What is the potential difference, $V _ { G } - V _ { D }$ , between points $G$ and D?
(b) What is the potential difference, $V$ A - $V _ { \mathrm { G } }$ , between points $\mathrm { A }$ and $\mathrm { G }$ ?