Faraday’s Law of Electromagnetic Induction

The relationship between the changing magnetic field and the induced emf is expressed in terms of magnetic flux φ_B linked with the surface of the coil.

dφ_B = B.ds

The magnetic flux for the entire surface is obtained by summing such contributions over the surface. Thus,

dφ_B = ∑B.ds

The SI unit of magnetic flux is weber (Wb), where 1 Wb = 1 Tm².

In analogy with electric lines, the number of magnetic lines intersecting a surface is proportional to the magnetic flux through the surface.

Faraday’s law states that an emf is induced across a loop of wire when the magnetic flux linked with the surface bound by the loop changes with time. The magnitude of induced emf is proportional to the rate of change of magnetic flux. Mathematically,

|ε| = dφ_B/dt

1 V = 1 Wb s^–1