Lessons from Gauss' Law

One thing we should talk about is electric flux. The electric flux through a surface is a measure of the number of electric field lines passing through a surface. Remember this in a few weeks when we talk about magnetic flux!

Another lesson. Let's say you have a charged sphere, and the charge Q is distributed symmetrically over the sphere. The electric field outside that sphere is the same as that from a point charge Q located at the center of the sphere.