A circuit consists of a 11.5-mH coil,a 9.0-V battery,a parallel combination of a 10-Ω resistor and a 6.0-Ω resistor,and a switch,all in series.What is the time constant of this circuit?
A) 7.2E-4 s
B) 3.1E-3 s
C) 1.2E-3 s
D) 2.8E-2 s
E) This circuit has 2 time constants.

Question

A circuit consists of a 11.5-mH coil,a 9.0-V battery,a parallel combination of a 10-Ω resistor and a 6.0-Ω resistor,and a switch,all in series.What is the time constant of this circuit?
A) 7.2E-4 s
B) 3.1E-3 s
C) 1.2E-3 s
D) ​2.8E-2 s
E) ​This circuit has 2 time constants.

Quizplus · Accepted Answer

The time constant (τ) for an RL circuit is given by τ = L/R_eq, where L is the inductance and R_eq is the equivalent resistance. The equivalent resistance of the parallel resistors is 1/(1/10 + 1/6) = 3.75 Ω. Thus, τ = 11.5 mH / 3.75 Ω = 3.1E-3 s.

A Circuit Consists of a 11