Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Reactance and Inductance of an inductor

  1. Nov 11, 2008 #1
    a. The reactance of an inductor is 100 ohms at 2kHz. What is the inductance of this inductor??

    b. At what frequency is the reactance of a 3.5-mH inductor equal to 10 ohm?

    I am not even sure what equations to use for these two questions. I know that for a the inductive reactance equation is XL = wL, but here I have two unknowns, XL and w so I am not sure what equation to use. For b the frequency equation I have is w = 1/LC but I do not know the capacitance.

    If anyone knows the equations that I would use for these two I would appreciate the help ASAP!! :)
  2. jcsd
  3. Nov 11, 2008 #2


    User Avatar
    Science Advisor
    Gold Member

    a) you have only one unknown because the angular frequency [tex] \omega[/tex] is simply related to frequency by [tex]\omega=2\pi f[/tex] .

    b) Use the same inductance equation--not the capacitance equation you wrote down for b)!!--solving this time for frequency.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook