Which of the following describes inductive reactance?

• A. The opposition to changes in voltage
• B. The ability for a device to store electrostatic charge
• C. The opposition to changes in current
• D. The rate at which the chemical reaction in a battery takes place.

Answer: (C)

Inductive reactance is the opposition an inductor presents to changes in current. When current tries to change, the changing magnetic field in the inductor induces an emf that opposes that change (Lenz’s Law), so the current flow is resisted. In AC circuits this opposition depends on frequency and inductance (X_L = 2πfL), and it causes current to lag the voltage.

That’s why the description that fits inductive reactance best is the opposition to changes in current. The other ideas describe different phenomena: resisting voltage changes relates to capacitors, storing electrostatic charge describes a capacitor’s function, and a battery’s chemical reaction rate is not about inductors.