Charge distributed over a spherical surface [concept question]

1. Feb 11, 2012

theBEAST

So in the case of a spherical conductor, if we have charge distributed over it the electric field inside will ALWAYS be zero. Even when we place a charge near the sphere the field inside is zero right?

And if we have a spherical insulator and we uniformly distribute the charge, the electric field inside is zero. HOWEVER if we place a charge near this sphere it will no longer be zero right?

2. Feb 11, 2012

BruceW

Your first paragraph is correct. But for the spherical insulator, it depends what you mean by uniformly distribute. Do you mean over the surface, or inside the insulator?

3. Feb 11, 2012

theBEAST

Over the surface

4. Feb 11, 2012

BruceW

Then yes, I think you got it all right :)

5. Feb 11, 2012

SammyS

Staff Emeritus
Be aware that when no external charge is present, the charge will be distributed uniformly over the surface of the spherical conductor. However, if we place a charge near the sphere, the charges on the surface of the sphere will be redistributed in such a way that any field that the external charge would have produced in the interior of the sphere are cancelled.