Electric Fields/Gauss's Law: Parallel insulating plates Here's the question: Two large, parallel, insulating plates are charged uniformly with the same charge density σ. What is the magnitude of the resultant electric field E ? The correct answer: zero between the plates, σ/E0 outside My question: Why is the field between them zero? I understand that there is at least a point in between them where the field is zero, but why is the whole field zero. As you get closer to one plate the force from that plate increases (whether it be attractive or repulsive) and the force from the other decreases. This means that the electric field is changing (the only way to get an unbalanced force). In addition, if the two add together, why do you get σ/E0 for the answer. Shouldn't each have a field vector of σ/E0 and when they add, 2σ/E0? I don't really see how they get σ/2E0 for each plate when they each have a charge density of σ. Finally, why does the field not vary with the distance? Is it just a property of a plate or am I just missing something?