Inductive Reactance Formula

Inductive reactance or simply reactance is not anything but the resistance of an inductive circuit. An inductor competes against the current in a coil which alters the direction and instantaneous magnitude. This opposition is comparable to resistance but always possesses a phase shift between voltage and current and dissipate zero power. As it has some alteration from the resistance, it is termed as reactance. Inductive reactance is denoted as XL. The SI unit is the ohm. The formula for reactance is given as

XL = 2πfL

Where the frequency is f, L is the inductance and XL is the inductive reactance.

Solved Examples

Example 1: An inductor of 2H is connected to a circuit at a frequency of 50Hz. Compute the inductive reactance of this circuit?


The given parameters are,

f = 50Hz

L = 2H

Inductive reactance formula is given as,

XL  = 2πfL

X = 2×3.14×50×2

XL= 628 Ω

Example 2: At what frequency does a 250 mH inductor have 3.5 kΩ of reactance?


The known parameters are,

XL = 3.5 kΩ = 3500Ω

f =? and

L = 250mH = 0.25H

Inductive reactance formula is articulated as,

XL  = 2π fL

\(\begin{array}{l}f = \frac{X_{L}}{2\pi L}\end{array} \)
\(\begin{array}{l}f = \frac{3500}{2\times 3.14\times 0.25}\end{array} \)

f = 2229 Hz

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