An RL Circuit A 12.6-V battery is in a circuit with a 30.0-mH inductor and a 0.150-Ω resistor, as

An RL Circuit

A 12.6-V battery is in a circuit with a 30.0-mH inductor and a 0.150-Ω resistor, as in Active Figure 20.27. The switch is closed at t = 0.

(a) Find the time constant of the circuit.

(b) Find the current after one time constant has elapsed.

(c) Find the voltage drops across the resistance when t = 0 and t = one time constant.

(d) What’s the rate of change of the current after one time constant?

FIGURE 20.27 A series RL circuit. As the current increases towards its maximum value, the inductor produces an emf that opposes the increasing current.