Which device provides inductive reactance in a circuit?

Which device provides inductive reactance in a circuit?

• A. Capacitor
• B. Inductor
• C. Resistor
• D. Transformer

Answer: (B)

Inductive reactance arises from a coil storing energy in its magnetic field and opposing changes in current. In an AC circuit, an inductor presents an impedance that is purely reactive (jωL), so its opposition to current grows with frequency (X_L = 2πfL). Because the current through an inductor lags the voltage by 90 degrees, the inductor effectively resists changes in the current more as the frequency increases. The device that provides this inductive reactance is the inductor. Capacitors oppose changes in voltage instead, producing capacitive reactance and causing current to lead voltage. Resistors don’t provide reactance (they’re a real resistance). A transformer uses mutual inductance for coupling, but the intrinsic inductive reactance comes from the inductor itself.

Inductive reactance arises from a coil storing energy in its magnetic field and opposing changes in current. In an AC circuit, an inductor presents an impedance that is purely reactive (jωL), so its opposition to current grows with frequency (X_L = 2πfL). Because the current through an inductor lags the voltage by 90 degrees, the inductor effectively resists changes in the current more as the frequency increases. The device that provides this inductive reactance is the inductor.

Capacitors oppose changes in voltage instead, producing capacitive reactance and causing current to lead voltage. Resistors don’t provide reactance (they’re a real resistance). A transformer uses mutual inductance for coupling, but the intrinsic inductive reactance comes from the inductor itself.