A Series RL Circuit with Inductance 6 $\Omega$ Is Connected to a 12

Multiple Choice

A series RL circuit with inductance 6.0 mH and resistance 20 $\Omega$ is connected to a 12.0-V battery of negligible internal resistance. The energy stored in the magnetic field of the inductor 8.0 s after the switch is closed is

A) 4.0 mJ.
B) 8.0 mJ.
C) 9.0 mJ.
D) 11 mJ.
E) 22 mJ.