Hi, this is my modified post since I've been told that I have to use certain format. I hope this is good now. 1. The problem statement, all variables and given/known data Copper (conductor) sphere of radious R with an spheric bubble inside placed at distance c from the center, with radius b. The metalic sphere has charge Q. 2. Relevant equations 1.- Find the electric potential inside the bubble 2.- Is the result modified if the bubble is not a sphere? 3. The attempt at a solution My main question is how the charge is distributed. Does the charge goes to the outside surface? or it's distributed between the outside and the inside surface. If the charge is distributed only on the outside surface the Electric potential is zero and then it doesn't matter the shape of the cavity. I'm I right?