1. The problem statement, all variables and given/known data Find the electric field near a large nonconducting plane of charge density sigma. 2. Relevant equations 3. The attempt at a solution I am working through chapter 24 of Giancoli and am having trouble understanding the concepts. This is example 24-4, and the magnitude of the electric field is found to be sigma / (2*epsilon_0). But shouldn't the total electric field be zero? The Gaussian surface would be a cylinder with tops parallel to the plane. The field points normally outward from the tops, but in opposite directions. Wouldn't this mean the total field is 0?