Consider a charged conductor, such as a charged metal electrode, in electrostatic equilibrium. That is, there is no current through the conductor and the charges are all stationary. One very important conclusion is that the electric field is zero at all points inside a conductor in electrostatic equilibrium. That is, . If this weren’t true, the electric field would cause the charge carriers to move and thus violate the assumption that all the charges are at rest. Let’s use Gauss’s law to see what else we can learn.