Problem 1 Four equal charges, each +qC, are located at four corners of a square. The Cartesian coordinates of the corners are (-1, -1, 0), (1, -1, 0), (1, 1, 0), and (-1, 1, 0). The z axis goes through the center of the square. You are to find the electrostatic field E due to the four charges on the z axis. 1. Since an electrostatic field is related to its potential as the gradient of the potential. One way to find E is to find a potential V of E at points on the z axis. 2. Find E at points on the z axis by applying Coulomb's law: 9 1 Απες R2 Compare the result with that obtained above. 3. Consider location on z axis where z is very large; that is, far away from the source charges. What does the solution you get tells you in that case? E = Ꭱ

Fig: 1