Inductors & AC Circuits (Homework) (RL Circuit)

[harkirat2009]

Homework Statement

What is the inductance in a series RL circuit in which R = 7.0 kΩ if the current increases to one half of its final value in 26 µs?

Homework Equations

am i correct in assuming that i should be using the time constant equation: Tau=L/R

The Attempt at a Solution

if i was correct in using this equation then:
Tau = ((26E^-6)*2))*.63212
R = 7000 Ohms

Tau*R=L
L=.23009168 H

 

[SammyS]

e^{-t/\tau}=\frac{1}{2} for t = 26 µs.

 

[harkirat2009]

thank you for your help