An Inductance L, Resistance R, and Ideal Battery of Emf

Multiple Choice

An inductance L, resistance R, and ideal battery of emf are wired in series and the circuit is allowed to come to equilibrium.A switch in the circuit is opened at time t = 0, at which time the current is /R.At any later time t the current i is given by:

A) (/R) (1 - e^-Lt/R)
B) (/R) e^-Lt/R
C) (/R) (1 + e^-Rt/L)
D) (/R) e^-Rt/L
E) (/R) (1 - e^-Rt/L)