Spherical capacitor energy problem

1. Jul 19, 2004

AgPIper

Show that the energy associated with a conducting sphere of radius R and charge Q surrounded by a vacuum is

U = k*Q^2 / (2R)

thanks

Last edited: Jul 19, 2004
2. Jul 20, 2004

Gza

Where are you having difficulty with the problem?

3. Jul 20, 2004

turin

Consider how much work you would have to do to bring all of the charge together from an infinite separation. In other words, how much work does it take to contract an infinitely large sphere of charge Q down to a small sphere of radius R?