For the ideal RL circuit shown, the resistance is `R=10.0Omega`, the inductance is `L=5.0 H` and the battery has voltage `xi_("bat") = 12` volts. Some time after the switch S in the circuit is closed, the ammeter in the circuit reads `0.40A`. If the rate at which energy is being stored by the inductor at this instant is `(16)/(x)` Watts, what is the value of x?

Options

A. 3
B. 4
C. 5
D. None of these

Answer

C

Explanation

`(dU)/(dt)=(Lidi)/(dt)=i(V_(L))=i(V-V_(R))=0.4(12-0.4xx10)=3.2"Watts"=(16)/(5)"watts"impliesx=5`