A varying current in a coils charge from 10 A to zero in `0.5 s` .If the average emf induced in the coils is 220 V , the self- inductance of the coils is

Options

A. 5 H
B. 6 H
C. 11 H
D. 12 H

Answer

C

Explanation

Initial current `(I_(1))=10 A`, Final current `(I_(2))=0`, Time (t) = 0.5 sec and induced e.m.f. `(epsilon)=220V`.
Induced e.m.f. `(epsilon)`
`=-L(dI)/(dt)=-L((I_(2)-I_(1)))/(t)=-L((0-10))/(0.5)=20 L`
or, `L=(220)/(20)=11 H`