# Modification to metal sphere problem

1. Feb 21, 2006

### cherrios

This problem is somewhat similar to the one I had posted yesterday.

There is a metal spehre, radius=x, that it surrounded by a conducting shell (also spherical) that has an inner radius=y and outer radius=Z. the total charge is 4 micro Coloumbs--> 1 micro Coloumb on the inner sphere, and the rest is distributed in the shell

1)Find electric field between the outer surface of the metal sphere and the inner radius of the conducting shell.

Would I need to take a Gaussian surface between the outer surface of the metal sphere and inner radius of the conducting shell? And also, how would I find the surface charge density on the inner and outer surfaces of the conducting shell?

2. Feb 21, 2006

### gulsen

Assuming that you have no induction and uniform chage density, the outer shell will not contribute to the electric field, since it has no charge between it and inner shell. You simply have $$q_{in} = 1\mu C$$, and by Gauss's law for a spherical shell
$$\int \vec{E}.d\vec{A} = \int EdA = E \int dA = E(4 \pi r^2) = \frac{q_{in}}{\epsilon_0}$$, which will yield E(r).