A solid sphere carries a uniform, surface-charge density. The sphere is surrounded by a linear dielectric with electric susceptibility, κ. For which system is the electrostatic energy the largest. a) For the sphere alone. b) For the sphere and the dielectric. c) Both systems have same electrostatic energy. Now I know, because my teacher told us, that the correct answer is a). I don't really understand why though. Can anyone explain? I can see that the dielectric would get polarized in such away that the total polarization is proportional to the total field (since the dielectric is linear). But that's pretty much all. Also, I am confused why it doesn't matter whether the sphere carries a positive or negative charge density. Also the answer seems quite weird to me. Suppose you have the sphere first and then surround it by the dielectric. According to the answer the electrostatic energy has now decreased! But where has it gone? Is the energy stored in the polarization and don't we count that or what?