A Simple Series Circuit Contains A $6.0 - \Omega$ Resistor, an Ideal

Multiple Choice

A simple series circuit contains a $6.0 - \Omega$ resistor, an ideal $15 - \mathrm { V } D C$ power supply, and an $18 - \mathrm { H }$ inductor. What the time constant of this circuit?

A) $0.33 \mathrm {~s}$
B) $110 \mathrm {~s}$
C) $3.0 \mathrm {~s}$
D) None of the given answers are correct.