I think I am misunderstanding some point about conductors and fields within them. I have been told that within a conductor, the charge is null because the inside field is null, and all of the charges are on the surface.
Does it mean that the NET charge within an uncharged conductor is null, although there are electrically neutral atoms (with their electrons and protons cancelling) inside the uncharged conductor? If so, in this case, both within the conductor and outside it the net charge is null, isn't it?
Best Answer
The statement, "all of the charge is on the surface" is only true in a static case of a charged conductor. There are other forces at work. For example, when there is current we have resistance--which tends to cause the EMF to push some of the carriers into the material. That's why the cross section is used in defining resistance rather than just the perimeter of the cross section. For an uncharged conductor, you can think of it as the two polarities of charges battling it out for the surface, and the result is no extra charge on the surface or within the conductor, either way. An uncharged conductor is neutral at any point in or on the conductor (unless there's an external field).