Two charges are arranged at corners of a square which has a side length of L = 0.25 m. The values of the charges are q1 = −3.3 × 10−6 C and q2 = +4.2 × 10−6 C. (a) Find the electric potential at points A and B. (b) If a third charge q3 = +2.1 × 10−6 C is placed at corner A, determine the electric potential energy of the system.