The most widespread model of Faraday's law states: The electromotive force encompassing a closed path is equivalent to the negative of the time rate of charge of the magnetic flux enclosed by the pathway. Faraday's Law of induction generates use of the magnetic flux through a theoretical surface whose periphery is a wire loop.

Since the loop may be moving, we write for the surface. The magnetic flux is specified by a surface integral. Faraday's law of induction says the wire loop acquires an EMF. Faraday's law of induction says the wire loop acquires an EMF. Faraday's law states that the EMF is also given by the rate of change of the magnetic flux.