what is inductive reactance?

Answer 1

When the current flowing through an inductor continuously reverses itself, as in the case of an ac source, the inertia effect of the cemf is greater than with dc. The greater the amount of inductance (L), the greater the opposition from this inertia effect. Also, the faster the reversal of current, the greater this inertial opposition. This opposing force which an inductor presents to the FLOW of alternating current cannot be called resistance, since it is not the result of friction within a conductor. The name given to it is INDUCTIVE REACTANCE because it is the "reaction" of the inductor to the changing value of alternating current. Inductive reactance is measured in ohms and its symbol is XL.
Hope this will help.

Answer 2

Inductive reactance [called impedance] is the opposition to changes in current flow and is measured in ohms. Unlike a Resistor an Inductive reactance offers no opposition to a steady state DC current however it opposes the increase in initial current flow when a DC voltage is applied and also opposes the decrease in current when the DC voltage is removed. Inductance is normally associated with circuit elements called coils and a coil`s inductance value is measured in units called henrys. Inductive reactance in a coil is directly proportional to the inductance value in Henrys and also directly proportional to the frequency of the applied ac voltage. In a purely inductive circuit [ no resistive elements and no capacitive elements ] the inductance causes the ac current to lag the ac voltage by 90 degrees and thus no power is absorbed by a pure inductor when an ac voltage is applied. Power is calculated by multiplying voltage times current times the cosine of the phase angle between the voltage and current. The cosine of 90 degrees is zero and consequently when you calculate the power in a purely inductive ac circuit you always come up with zero no mater how high the impedance, voltage and current are in the circuit. The simple formula offered for calculating X of L [impedance] by one of the other people submitting an answer is only valid for pure sine waves. A much more complicated formula requiring calculus is required to determine the impedance for complex waveforms.

Answer 3

Inductive reactance is the opposition of a coil of wire to the change of a current flowing through it. The symbol used is XL, and is measured in ohms. Before you can get a value of XL you need to know the value of the inductance, such as 1 milli-Henry, or so many micro henries and the frequency of the signal that you want to know what the XL of this coil, or inductor is going to be. The formula to determine XL is simple. XL=2^pifL. As an example; 2x3.14x1000 Hz(the "f" in the equation)x1(.001 Henry) will equal 6.28 ohms reactance. This means that the coil, or inductor will offer a resistance of 6.28 ohms to the passage of a signal of 1000Hz flowing through the inductor. I hope this offers a better explanation than the, in my opinion, BS that bnyxis offered.