Inductive Reactance:
Within an inductive AC circuit, the current is continually modifying and is continuously inducing an EMF. Since this EMF opposes the continuous change in the flowing current and its effect is measured in ohms. That opposition of the inductance to the flow of an alternating current is known as inductive reactance (XL). Equation (8-1) is the mathematical representation of the current flowing in a circuit in which holds only inductive reactance.
I = E / XL (8-1)
where
I = effective current (A)
XL = inductive reactance ( ? )
E = effective voltage across the reactance (V)
The value of XL in any circuit is dependent on the inductance of the circuit and on the rate at that the current is changing by the circuit. This rate of modification depends on the frequency of the applied voltage. The Equation (8-2) is the mathematical representation for XL.
XL = 2ΠfL
where
Π = ~3.14
f = frequency (Hertz)
L = inductance (Henries)
The magnitude of an induced EMF in a circuit depends on how fast the flux which connects the circuit is changing. Within case of self-induced EMF (like as in a coil), a counter EMF in the coil is induced due to a modification in current and flux in the coil. That CEMF opposes any change in current and its value at some time that will depend on the rate at that the current and flux is changing at that particular time. In a purely inductive circuit and the resistance is negligible in comparison to the inductive reactance. A voltage applied to the circuit must always be equal and opposite to the EMF of self-induction.