Gauss formula generally refers to Gauss theorem. Gauss law is also called Gauss flux theorem, or divergence theorem, Gauss divergence theorem, Gauss Ostrogradski formula, Auschwitz theorem or Gauss formula (usually Gauss theorem refers to this theorem, and there are other theorems with the same name).

In electrostatics, Gauss's law shows the relationship between the sum of charges on a closed surface and the electric flux integral of the electric field generated on the closed surface. ?

The electric flux passing through any closed surface (called Gaussian surface) S in electrostatic field is equal to the algebraic sum of all charges in the closed surface divided by the dielectric constant in vacuum, regardless of out-of-plane charges.

Gauss's law of electrostatic field is similar to Ampere's law of magnetic field, and both of them are concentrated in Maxwell's equations. Because of the mathematical similarity, Gauss's law can also be applied to other physical quantities determined by inverse square law, such as gravity or irradiance.

Coulomb's law and Gauss's theorem can be used to solve the electric field strength. E. Coulomb's law and the principle of field strength superposition can generally be used to solve the field strength of point charge and point charge system. In principle, the field strength of a continuously distributed charged system can also be solved, but for specific problems, the continuous distribution function of charge must be known.

There are some limitations in solving the field strength by Gauss theorem, and generally only the field strength with a certain symmetric distribution can be solved.

There are two steps to solve the field strength with Gauss theorem:

1. It is necessary to qualitatively analyze the field strength generated by the charged system involved and make clear the distribution law of the field strength direction and size.

2. According to the law of field intensity distribution, judge whether it can be solved by Gaussian theorem, and if so, construct a suitable Gaussian surface to solve it.

To construct a Gaussian surface, two conditions must be met:

1, the field strength point must be on the Gaussian plane.

2. The field strength of each point or part on the Gaussian surface is equal.

On this basis, the shape and size of Gaussian surface can be arbitrarily selected in principle, so that the field strength E to be solved can be moved beyond the integer multiple of Gaussian theorem, and the field strength generated by the charged system involved at the point to be solved can be obtained.