1. The problem statement, all variables and given/known data (a) Consider two concentric spherical shells, of radii a and b. Suppose the inner shell carries a charge q and the outer shell carries -q (both of them uniformly distributed over the surface). Calculate the energy of the electric field in this configuration. 2. Relevant equations 3. The attempt at a solution I was just wondering if this would result in a net charge of zero, thus no electric field? And consequently no energy?