We take two coils, and they are placed close to each other. The two coils are P- coil (Primary coil) and - coil ( Secondary coil). To the P-coil, a battery, and a key is connected wherein the -coil a galvanometer is connected across it. When there is a change in the current or magnetic flux linked with two coils an opposing electromotive force is produced across each coil, and this phenomenon is termed as Mutual Induction.
The relation is given as:
ϕ = I
ϕ = M I
Where M is termed as the mutual inductance of the two coils or the coefficient of the mutual inductance of the two coils. The rate of change of magnetic flux in the coil is given as,
Where,
- μ0 is the permeability of free space
- μr is the relative permeability of the soft iron core
- N is the number of turns in coil
- A is the cross-sectional area in m2
- l is the length of the coil in m
