Inductive reactance is a property of inductors (coils or solenoids) in electrical circuits and is a measure of their opposition to changes in the flow of alternating current (AC). It is analogous to electrical resistance but specific to the behavior of inductors with AC signals. Inductive reactance is represented by the symbol "XL" and is measured in ohms (Ω).

The key points about inductive reactance are as follows:

1. **Definition:** Inductive reactance is the opposition offered by an inductor to the change in the current flow through it when an AC voltage is applied. In other words, it is a measure of how much the inductor resists the changes in the current direction and magnitude caused by an alternating voltage.

2. **Dependence on Frequency:** The value of inductive reactance depends on the frequency of the AC signal. It is directly proportional to the frequency of the signal. The higher the frequency, the greater the inductive reactance.

3. **Mathematical Relationship:** The mathematical relationship for inductive reactance is given by the formula:

   XL = 2πfL

   Where:
   - XL is the inductive reactance (in ohms).
   - π (pi) is approximately 3.14159.
   - f is the frequency of the AC signal (in hertz, Hz).
   - L is the inductance of the inductor (in henrys, H).

4. **Phase Shift:** In a circuit with inductive reactance, the voltage across the inductor lags behind the current by 90 degrees in a pure inductive circuit. This means that the current leads the voltage by 90 degrees.

5. **Effect on AC Circuits:** Inductive reactance is used in AC circuits to control and limit current flow, to block high-frequency components, and to alter the phase relationship between voltage and current. It is often used in combination with capacitive reactance to create various filter circuits and resonant circuits.

6. **Impedance:** In an AC circuit, the impedance (Z) of an inductor is a combination of its inductive reactance (XL) and any resistance (R) it may have:

   Z = √(R² + XL²)

   The impedance is the overall opposition to the flow of AC current, taking into account both resistance and reactance.

Inductive reactance is a fundamental concept in AC circuit analysis and is crucial for understanding the behavior of inductors in alternating current circuits. It plays a significant role in various applications, including filtering, power factor correction, and tuning circuits.