Explain the term self-induction of a coil
Self – Induction –
It is the property of an electric circuit or coil by virtue of which it opposes any change of flux or current in it by inducing a current in itself is called self- induction. In another words we can say “self-induction is the inertia of electricity “. Due to self -induction an electric circuit resist any change of current through it .
As we know magnetic flux linked with a coil is directly proportional to the current flowing through the circuit
i.e. ɸ α I ( ɸ= flux linked with the coil, and I is the current in the circuit )
ɸ = LI ( L is the constant called coefficient of self- induction or self-inductance or only inductance . )
If current I = 1 ampere, then flux ɸ= L . so we can define self-induction is the flux linked with the coil when unit current passes through the coil.
as we know,
emf e= – dɸ/dt
e= -d (LI)/ dt
e= -L ( dI/dt)
L= – e/(dI/dt)
So we can define self-inductance of a circuit is numerically equal to the induced emf setup in it when the rate of change of current through it is unity.
Unit of self-inductance is Henry (H) . We can define self-inductance of a coil is one Henry if 1 volt emf induced in the coil when rate of change of current through the coil is unity.