I was studying the electric field and potential of a solid sphere of charge. In my textbook it is mentioned that we distribute electric charge in the interior of the sphere. I had learnt that in a conductor excess charge always resides on its surface. Then how can electric charge if distributed in the interior of the solid sphere not goto the outer surface ?
I thought that if the solid sphere is an insulator then wherever we deposit the charge it stays there and so electric charge could reside in the interior. While in the case of a solid conducting sphere the charge wouldn't reside in the interior and move on to the surface. Is this logic correct ?