An Inductance L, Resistance R, and Ideal Battery of Emf $\varepsilon$

Multiple Choice

An inductance L, resistance R, and ideal battery of emf $\varepsilon$ are wired in series. A switch in the circuit is closed at time 0, at which time the current is zero. At any later time t the emf of the inductor is given by:

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