A Resistor and an Inductor Are Connected in Series to a Battery

Multiple Choice

A resistor and an inductor are connected in series to a battery. The battery is suddenly removed from the circuit. The time constant for of the circuit represents the time required for the current to decrease to

A) 25% of the original value.
B) 37% of the original value.
C) 50% of the original value.
D) 63% of the original value.
E) 75% of the original value.