- #1

My question is under what circumstances is this a "legal" move? It can't just be when we have a uniform electric field, since we can also apply this simplified version of Gauss' law to a spherical surface around point charge whose radius can be chosen to be whatever you want (i.e. [itex]E \cdot 4 \pi r^{2} = \frac{Q}{\epsilon_0}[/itex])

I came to the conclusion that this is only valid when the electric field is constant at all points on each area being considered, which made sense to me since then E would be constant with respect to the surface area elements in the integral and we can consequently take it out. Is this sort of the right way of thinking about it? Thanks