#### Question 4

Four point charges, A, B, C, and D, are placed at the corners of a square with side length L. Charges A, B, and C have charge +q, and D has charge

-q. Throughout this problem, use k in place of 1/4πε0.

Part A: If you calculate W, the amount of work it took to assemble this charge configuration if the point charges were initially infinitely far apart, you will find that the contribution for each charge is proportional to kq²/L. In the space provided, enter the numeric value that multiplies the above factor, in W.

Part B: Which of the following figures depicts a charge configuration that requires less work to assemble than the configurationin the problem introduction? Assume that all charges have the same magnitude q.

(figure provided in the solution)