Electric field in a conductor with an internal cavity

[Silversonic]

I'm not entirely sure if this is meant to be in the "advanced physics" section, it's for my undergraduate degree anyway.

Homework Statement

A conducting sphere of radius R, carries a total charge of q. It is surrounded by an electrically neutral conducting shell with an inner radius, a, and outer radius, b.

[PLAIN]http://img812.imageshack.us/img812/7357/59847545.png

What is the electric field in the region R < r < a?

The Attempt at a Solution

I'm confused on whether there is or isn't an electric field. I've already answered the question asking me to find the electric field for r < R and a < r < b as zero due to Gauss' law (the Gaussian surface requires and electric field of 0 to pass through it). But I'm confused about this one between the sphere and the conducting shell. I am pretty sure that there is an electric field (it's the region between positive and negative charges, why wouldn't there be?), but if there was, how would I calculate it?

 

[Feldoh]

There is an electric field in that region and you'd solve it like any other Gauss's law problem. Pick your surface, find how much charge is enclosed.

What surface would you pick?

 

[Silversonic]

There is an electric field in that region and you'd solve it like any other Gauss's law problem. Pick your surface, find how much charge is enclosed.

What surface would you pick?

Understood, thanks :)