# Two spheres with given potential, what's their charge?

1. Apr 18, 2007

### hooker27

Hi
This shouldn't be very difficult: I have two spheres (made of Cu -> conductors) with given radius a (both), the distance of their centers is h. Now I know that the potential on the first sphere is zero and on the other 1000 Volts (the potential at infinity is zero).
I must determine the force that pulls the spheres together (or apart).

I think that what I must find is the charge of each of the spheres, then the force is easy via Coulomb's law. I also think that the charge on the spheres should be like:

Q = CU

where Q is vector of charges, C is 2x2 matrix of coefficients Cij and U is a vector of potentials on the spheres (0V and 1000V in this case). The Cij coefficients should be given by the geometry of the problem, but I don't know how tu determine them. But perhaps I am completely wrong.

Could anyone point me in the right direction? Thanks a lot. It's pretty urgent, btw:-)