Two point charges Q1 = Q and Q2 = Q are on the x-axis at x = +L and x = -L and a third point charge Q3 = Q is on the y-axis at the point y = L as shown in the Figure. What is the electric potential difference, ∆V = V2-V1 between the point P2 at the midpoint of the line between Q1 and Q3 and the point P1 at the origin?
