# Concept question

1. Feb 6, 2005

### NotaPhysicsMan

Ok,

Suppose I have two balls that come into contact to make their charges say q1=q2. Would the charges be equal if the balls were of different size?

I'd say yes, because mass is not relevant in Coulomb's law.

2. Feb 6, 2005

### Andrew Mason

If the balls are conductors, the charges on each ball will move until all charge is at the same electrical potential. Electrical potential on the surface of a conducting sphere is:

$$V = \frac{Q}{4\pi\epsilon_0R}$$

If the balls are of different size (radius) but equal charge, the potentials will not be the same. So when they touch the charges will move so that the potential V for each is the same (ie. a sphere half the radius as the other, will have half the charge as the other).

AM

Last edited: Feb 6, 2005