The equipotential surfaces for two point charges are shown i

The equipotential surfaces for two point charges are shown in the figure, with the value of potential marked on the line for each surface. What is the potential difference, V_G - V_D, between points G and D? What is the potential difference, V_A - V_G, between points A and G?

Solution

15)V_G-V_D = -160-0 = -160V(subtract the potential at the points using the fact that points in an equipotential surface have same potential)

V_A - V_G = 160-(-160) = 320V(subtract the potential at the points using the fact that points in an equipotential surface have same potential)