1. The problem statement, all variables and given/known data A point charge of strength q1 = -4 µC is located at the center of a thick, conducting spherical shell of inner radius a = 2 cm and outer radius b = 3 cm. The conducting shell has a net charge of q2 = 5 µC (a) Calculate the surface charge densities on the inner (sa) and outer (sb) surfaces of the spherical shell. 2. Relevant equations Gauss's law Surface area of sphere - 4*pi*r^2 3. The attempt at a solution So I thought that on a conductor, the charge was all on the outside, so there would no charge on the inner surface, but that was wrong, so I'm at a lose on how to approach this. Gauss's law give me the electric field through an area, right? And then relates that to the charge enclosed, which I know? I might know the equation, but the concepts and how to apply them escape me.