# Divergence Theorem Problem

**1. The problem statement, all variables and given/known data**

Use the divergence theorem (and sensible reasoning) to show that the E field a distance r outside a long, charged conducting cylinder of radius r

_{0}which carries a charge density of σ Cm

^{-2}has a magnitude E=σr

_{0}/ε

_{0}r. What is the orientation of the field?

**2. Relevant equations**

q=∫E.dAε_{0}

**3. The attempt at a solution**

Completely lost really, not even sure where to start. The dimensions of σ mean that it can only be used with the surface integral (I think), and so every time I start playing around with the equations, I end up not using the divergence theorem at all. Not even sure if the second equation is relevant, just included it because I have a feeling it might be useful.

http://ift.tt/1faDWXI

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