A varying current in a coil changes from 10A to zero in

A varying current in a coil changes from 10A to zero in 0.5 sec. If the average e.m.f induced in the coil is 220V, the self-inductance of the coil is

Initial current (I₁) = 10 A; Final current(I₂)= 0; Time (t) = 0.5 sec and induced e.m.f. (ε) = 220 V. Induced e.m.f. (ε)

= - L	dI	= - L	(I₂ - I₁)
	dt		t

= - L	(0 - 10)	= 20L
	0.5

or, L =	220	= 11 H
	20

[where L = Self inductance of coil]