Solving Gauss's Law Problem: Determine Electric Field on/in Sphere

[samblue]

Homework Statement

Ok so I', having some problems with Gauss's law. I know what it is, but I still can't get the answers right.

A metallic sphere of diameter 2*10-2m has been given a charge of 2 nC. State Gauss's law. Use this to determine the electrical field at the surface of the sphere. What is the electrical field inside the field?

Homework Equations

integral (E.dA)=Qenclosed/permitivity of free space

The Attempt at a Solution

the fist part is the equation written below.

However I am not sure about the next part. How do I distinguish between the charge inside the spehere and the charge on the surface?

Thanks

 

[Doc Al]

Assuming electrostatic equilibrium, what's the charge inside a conductor?

 

[samblue]

Assuming electrostatic equilibrium, what's the charge inside a conductor?

Not really sure. Is it zero? Becasue all of the charge passes through it?

 

[Doc Al]

Not really sure. Is it zero? Becasue all of the charge passes through it?

Key fact (where electrostatic equilibrium holds): The electric field is zero everwhere inside a conductor. All the (net) charge on a conductor lies on its surface.

 

[samblue]

thanks