I was reading this question out of a book. A small metal sphere hangs by an insulating thread within a larger hollow conducting sphere. A conducting wire extends from the small sphere through, but not touching, a small hole in the hollow sphere. A charged rod is used to transfer positive charge to the protruding wire. And it wants to know what objects will be charged. This is not a homework question just wondering. SO just the inner smaller sphere will have positive charge on it, since the charge can't flow across the insulating thread. But the electric field inside a conductor is zero so the positive charge on the smaller sphere will attract negative charge on the inner shell of the larger sphere and then leave positive charges on the very outer shell of the sphere. But what if the smaller sphere was hanging to the shell by a wire. Would the charge then just spread out uniformly to make the E field inside the conductors? And then also why would the positive charge leave the rod to the metal sphere. Is the E field pushing the charge onto the sphere. And is the E field of the rod causing the metal sphere to be polarized and this attracts the positive charge from the rod?