A series circuit contains a 12-V battery,a 3.3-Ω resistor,and a 4.4-mH inductor.If the switch to the battery is closed at t = 0,find the time required for the current in the circuit to reach 63% of its final value.
A)1.3E-3 s
B)1.5E-2 s
C)7.5E+2 s
D)1.6E-2 s
E)1.1E-4 s

Question

Quizplus · Accepted Answer

The time required for the current in an RL (resistor-inductor) circuit to reach 63% of its final value is given by the time constant, τ = L/R, where L is the inductance in henries and R is the resistance in ohms. Here, L = 4.4 mH = 4.4E-3 H and R = 3.3 Ω. Thus, τ = (4.4E-3 H) / (3.3 Ω) = 1.333E-3 s, which is approximately 1.3E-3 s.

A Series Circuit Contains a 12-V Battery,a 3