Two charges Q1 = 1.0 nC and Q2 = -3.0 nC are on the xy plane as shown in the figure below. Let a = 5.0 cm. Q2 (x,y) = (0,2a) Q 1 O X (x, y) = (a,0) What is the electric potential at the origin if we take the potential at infinity to be zero? O -150 V Correct Answer O -90 V