1. The problem statement, all variables and given/known data Consider a uniformly polarized electret in the shape of a cylinder with height h and radius 10h. The polarization in the dielectric is P, parallel to the cylinder axis. a) calculate surface and volume bound charges b) calculate the electric field at the center of the cylinder. Since the radius is large compared to the height, you may neglect edge effects. 2. Relevant equations σb = P⋅n ρb = - ∇⋅P 3. The attempt at a solution I've already worked out part a and found there's a surface bound charge of P on the upper surface, and -P on the lower surface. I tried to do part b by finding the potential in the middle of the cylinder due to the top and bottom surface separately, then adding them together to get the total potential, then taking the gradient to find the electric field. When I tried to do this the potential from the top and bottom surfaces cancel giving me 0 total potential and thus no electric field, but I know this doesn't make any sense since there should be field lines going from the positive surface to the negative surface. Can someone help point me in the right direction?