A series LR circuit includes a 9.0 V battery, a resistance of 0.20 Ω, and an inductor. When the switch is closed, the circuit exhibits a time constant of 200 ms. What is the inductance of the circuit?
A) 42 mH
B) 15 mH
C) 32 mH
D) 40 mH
E) 22 mH

Question

Quizplus · Accepted Answer

The time constant of a series LR circuit is given by:

τ = L/R

where τ = 200 ms, R = 0.20 Ω.

Solving for L, we get:

L = τ R = (0.200 s)(0.20 Ω) = 0.040 H = 40 mH

Therefore, the inductance of the circuit is 40 mH. Therefore, the correct answer is (D).

A Series LR Circuit Includes a 9