# Homework Help: Reactance and Inductance of an inductor

1. Nov 11, 2008

### Kathi201

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. Nov 11, 2008

### marcusl

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

b) Use the same inductance equation--not the capacitance equation you wrote down for b)!!--solving this time for frequency.

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