# Basic principle of electrostatics?

1. Jun 18, 2010

### planesinspace

I seem to be having trouble grasping a very basic principle in electromagnetism. I have been told, in numerous places, that the electric field inside a conductor is zero. (Electrostatics). Yet I keep coming across problems in the textbook like this one:

"Use Gauss's Law to find the electric field inside a uniformly charged sphere (charge density 'ro')."

where for Q[enclosed] = charge density * volume

However, don't all the charges move to the surface of the sphere? and the electric field IN the sphere is subsequently zero?

2. Jun 18, 2010

### Feldoh

uniformly charged sphere =/= conductor in all cases.

3. Jun 19, 2010

### Studiot

Yes this is true so long as there is not current flowing - all charges are stationary.

As soon as a current flows there is a field.

4. Jun 19, 2010

### ZapperZ

Staff Emeritus
The OP did indicate that this is Electrostatics. So there is no need to make such qualification.

Feldoh has sufficiently answered the question here, that just because one has a spherical charge, it doesn't mean that one also has a conducting sphere.

Zz.