When current in a coil changes with time, how is the back e.m.f. induced in the coil related to it ?

Whenever current in a coil is changed, an e.m.f. is induced in the same coil. This property of coil is due to ___________.

When current in a coil changes to 2 ampere from 8 ampere in 3xx10^(-3) , the e.m.f. induced in the coil is 2 volt. The self-inductance of the coil in millihenry is

When the current in a coil changes from 2 A to 4 A in 0.05 s, an e.m.f. of 8 V is induced in the coil. The coefficient of self-induction of the coil is

The current in a coil decreases from 5 A to 0 in 0.1 sec. If the average e.m.f induced in the coil is 50 V, then the self inductance of the coil is

To induce an e.m.f. in the coil

The current in the coil changes from 3A to 6 A in 3sec. If the induced e.m.f. in the coil is 60 V, then self inductance of the coil is