Inductive Reactance

Inductive reactance is a circuit element’s opposition to an alternating current caused by the build up of magnetic fields in the element due to the current. Inductive reactance (Xl) is proportional to the signal frequency (F) and the inductance (L).

X_{l}=2pi FL

F=frac{X_{c}}{2pi L}

L=frac{X_{c}}{2pi F}

More info: http://en.wikipedia.org/wiki/Inductive_reactance