Hi, I think I need some help understanding exactly what my book means when it says "the electric field undergoes a discontinuity passing a surface charge." In fact, using Gauss' law my book directly calculates by how much the field is discontinous, so definately I must be missing something. What exactly is meant by the field being discontinous? I thought it meant that the strength of the field jumps but it can't be so from what I know about electric fields. For instance, the book considers a metal plate of positive charge and uses that as an example of something where the field is discontinous. But the field, from Coulombs law must be extremly big, approaching infinity the closer you get to the surface of the plate, from either side. Thus infinitesimally close to either side of the plate the electric field is infinite point out perpendicular to the surface, correct? How does discontinuity come into the picture?