Self induction is the property of a coil by virture of which the coil oppose any change in the strenght of current flowing through it by inducting an e.m.f. in itself.
Self induction represents electric inertia which is measured in terms of coefficient of self inductance
We can show that `L = (phi)/(I) = (-e)/(dI//dt)`
Read the above passage and answer the following questions :
An e.m.f. of 150 microvolt is induced in a coil when current in it changes from 5A ot 1 A in 0.2 sec. what is self inductance of the coil ?
(ii) How does self indcution of a coil represent its electric inertia ?
(iii) What is them implication of this property in our daily life ?

Explanation

Here, `e = 150 microvlot = 150 xx 10^(-6) V, dI = 5 - 1 = 4A, dt = 0.2 s L = ?`
From `e = Ldt//dt`
`L = (e xx dt)/(dI) - (150 xx 10^(-6) xx 0.2)/(4) = 7.5 xx 10^(-6) H`
(ii) On account of self induction, a coil oppose increase as well as decrease in strength of current flowing through it, i.e., the coil oppose the growth and decay of current through it. Hence, Self induction is rightly representing electric ineertia of the coil.
(iii) In our daily life, whatever habits, good or bad, we have developed, we tend to stick to them. None of us likes changes. we have to put in efforts. These are the values of life we learn form this property.