Physics Question #5

It has been a while since I've posted an interesting physics problem and I have been thinking that it would be good to post a new one. I just ran across this problem while familiarizing myself with the fundamentals of dynamo theory.

Imagine a copper disk rotating about its axis in a uniform magnetic field, H. The disk has a radius a and has a tangential velocity v at its periphery. A conducting brush is simply connected to the disk and the disks axis and has a negligible effect on the system. Will a current flow through the system? If so, what will be the value of this current?

Good luck and, as always, no searching Google or Wikipedia for the answer!