Question

Explain seld induction and mutual induction.

Answer 1

Self inductance is defined as the property of the coil due to which it opposes the change of current flowing through it. Inductance is attained by a coil due to the self-induced emf produced in the coil itself by changing the current flowing through it. It's given by the following:

$e=L\frac{dI}{dt}$

Where e is self induced emf, L is self inductance, I is current and t is time passed. The unit of self inductance, L is Henry.

Mutual Inductance between the two coils is defined as the property of the coil due to which it opposes the change of current in the other coil, or you can say in the neighboring coil. When the current in the neighboring coil is changing, the flux sets up in the coil and because of this changing flux emf is induced in the coil called Mutually Induced emf and the phenomenon is known as Mutual Inductance.

In short flux through second coil is directly proportional to current flowing in first coil, which is given by the following expression:

${\varphi }_2=M_{21}{I}_1$ and ${\varphi }_1=M_{12}{I}_2$

Where ${\varphi }_1$ and ${\varphi }_2$ is flux through coil 1 and coil 2 respectively, $I_1$ and $I_2$ is current in coil 1 and coil 2 respectively and $M_{12}=M_{21}=M$ is mutual induction.