Drop in EMF caused by Inductance is proportional to Rate of Change of Current

Physical Law
The drop in EMF $E_L$ caused by an inductor is proportional to the rate of change of current $I$ through the inductor:
 * $E_L = L \dfrac {\d I} {\d t}$

Also see
The constant of proportion $L$ is known as the inductance of the inductor.