# How can a conductor of uniform charge density exist

1. Sep 5, 2007

### sumit_rai

Please tell me if by gauss law total electric field inide a solid conductor is zero... how can uniform charge density exists....

Will there be any electric field inside a charged conductor ? or will it be always zero.

2. Sep 5, 2007

### sumit_rai

can there be an electric field inside a solid of uniform charge density

By Gauss law electric field inside a conductor is zero ... then how can there be an electric field inside a solid of uniform charge density. Please tell me .

3. Sep 5, 2007

### olgranpappy

Gauss' law tell you that there is no charge inside a conductor because
$$E=0\to\nabla \cdot E=0\to\rho=0$$

A solid of *uniform* charge density necessarily has a nonzero electric field inside it (and outside it) by gauss' law as well. If the solid is spherically symmetric then you can easily figure out what the field must be using the integral form of Gauss' law.

A conductor is not a solid of uniform charge density.

4. Sep 5, 2007

### olgranpappy

double posting, eh? That's not nice.

the electric field is zero inside a conductor, though not "by gauss' law". It is by gauss' law that you know there is no charge in the meat of a conductor... oh, I'm repeating myself, this is answered on your *other* thread.

5. Sep 5, 2007

### sumit_rai

Thanks for a reply , another doubt that i have

If a conductor cannot be a solid of uniform charge density.... then what type of material is a solid of uniform charge density .... is it a mixture of conductor and non conductor... does it even exist ?

6. Sep 5, 2007

### sumit_rai

Thanks, for answering... sorry for double posting. I still have a doubt. its posted at the other post.

7. Sep 5, 2007

### olgranpappy

The approximation of continuous media is just that--an approximation.

A solid of uniform charge density is not a conductor.

8. Sep 6, 2007

### premagg

It can be felt very easily if u take this picture in your mind.
Since it is a conductor,so has number of free electrons.Hence any charge that is inside the conductor or any field if exists will be instantly taken care of by these particles.Hence there can't be any field or any charge inside conductor as in ELECTROSTATICS.