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

Ans. A/c to Faraday’s law of E.M.I , Back e.m.f induced in the coil , e = – L dI/dt  . Where L is the coefficient of self – inductance of the coil and dI/dt is the rate of change of current through the coil .