A thin, horizontal 10 cm x 10 cm copper plate is charged with 1.0 x 10^10 electrons. If the electrons are uniformly distributed on the surface, what is the strength of the electric field? I initially went to use the formula given in the text for a conductor where Electric field=n/Eo where n is the surface charge density and Eo is the permittivity constant . I can only get the right answer if I model it as an infinite plane of charge, though. Can you assume that this works even though it's so small?