Law of conservation of electricity

Let there be no dielectric and magnet in the electric field

P = 0 ε = 1 M = 0 μ = 1

the change in the electric field is accompanied by the same magnetic field as the movement of the charge



Constant field

rotB = μJ

With a changing field, this equation loses its meaning.
The current flowing out of any closed surface is equal to the decrease in the amount of electricity Q contained inside this surface.