I'm not sure what Gauss's law really means. "The electric flux through any closed surface is proportional to the enclosed electric charge." How does this apply to finding the electric field? apcentral.collegeboard. com/apc/public/repository/ap11_frq_physics_cem.pdf Look at parts 1 a and b. Part 1a is easy enough to do, but I want to really understand why Gauss's law applies here. collegeboard. com/apc/public/repository/ap11_physics_c_electricity_magnetism_scoring_guidelines.pdf Here are their solutions. (Remove the space before com in both links). The fact that the enclosed charge is zero does not tell you anything about the electric field, though, as evidenced by part (b). What if I draw a Gaussian surface next to, but not enclosing, a point charge? There is no enclosed charge, and no net flux, but there is still obviously an electric field. So why do they want Gauss's law used in these situations?