Foundational law of electromagnetism relating electric field and charge distributions
This article is about Gauss's law concerning the electric field. For analogous laws concerning different fields, see Gauss's law for magnetism and Gauss's law for gravity. For the Ostrogradsky–Gauss theorem, a mathematical theorem relevant to all of these laws, see Divergence theorem.
Gauss's law in its integral form is particularly useful when, by symmetry reasons, a closed surface (GS) can be found along which the electric field is uniform. The electric flux is then a simple product of the surface area and the strength of the electric field, and is proportional to the total charge enclosed by the surface. Here, the electric field outside (r > R) and inside (r < R) of a charged sphere is being calculated (see Wikiversity).