Reactance arises from which components?

Reactance arises from which components?

• A. Resistors
• B. Inductance or Capacitance
• C. Batteries
• D. Transformers

Answer: (B)

Reactance is the part of impedance that comes from components that store energy, not from those that simply dissipate it. Inductors store energy in a magnetic field and have inductive reactance that grows with frequency (X_L = ωL). Capacitors store energy in an electric field and have capacitive reactance that decreases with frequency (X_C = 1/ωC). Together, these energy-storage elements are what make impedance have a reactive (imaginary) component and cause current and voltage to shift relative to each other. Resistors just dissipate energy as heat and present a constant resistance, so they don’t create reactance. Batteries are energy sources, not impedance. Transformers involve magnetic coupling and behave inductively, but the core idea is that the energy-storage elements—inductance and capacitance—are the source of reactance.

Reactance is the part of impedance that comes from components that store energy, not from those that simply dissipate it. Inductors store energy in a magnetic field and have inductive reactance that grows with frequency (X_L = ωL). Capacitors store energy in an electric field and have capacitive reactance that decreases with frequency (X_C = 1/ωC). Together, these energy-storage elements are what make impedance have a reactive (imaginary) component and cause current and voltage to shift relative to each other.

Resistors just dissipate energy as heat and present a constant resistance, so they don’t create reactance. Batteries are energy sources, not impedance. Transformers involve magnetic coupling and behave inductively, but the core idea is that the energy-storage elements—inductance and capacitance—are the source of reactance.