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## Homework Statement

Imagine a solid, annular sphere. At the center of the hollow is a point charge +Q. The inner radius of the sphere is r0, and the outer radius is R. Assume the charge density p = p0/r (for r0 < r < R). Calculate using the integral form of Gauss's Law the electric field in all three regions:

0< r < r0

r0< r < R

R < r < infinity

## Homework Equations

[PLAIN]http://www.forkosh.dreamhost.com/mimetex.cgi?%5Coint_S%5Cmathbf%7BE%7D%5Ccdot%7Bd%7D%5Cmathbf%7BA%7D=%5Cfrac%7BQ%7D%7B%5Cepsilon_0%7D=%5Cfrac%7B1%7D%7B%5Cepsilon_0%7D%5Cint_V%5Crho(%5Cmathbf%7Br%7D)%5C,dV [Broken]

## The Attempt at a Solution

for 0 < r < r0

E(4 Pi r^2) = 1/e0 (p0/r)(4/3 pi r^3)

=> E = (1/3e0)p0

But this can't be right for because all of the r's cancel out. And since I can't do this one, I know I can't do the rest.

Thank you.

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