The book says that a hollow charged sphere has an equal potential at all points on and inside the sphere but the points inside the sphere have zero net electric field for they have no charge. If they have no charge, then how do they have a potential in the first place?
[Physics] Potential inside a hollow charged spherical shell
chargeelectrostaticspotential
Best Answer
There are two ways of answering your question. The first is that potential is defined up to an arbitrary constant, so you can define it to be any constant value inside the shell. The second way assumes that you mean the potential is zero at infinity. In that case:
You haven't said anything about the charge outside of the shell. The potential inside will be constant, but will be equal to the potential at the surface of the shell. That potential will have a nonzero value due to the charges outside.