Which statement best describes the function of an inductor?

Which statement best describes the function of an inductor?

• A. Transmits signal without loss
• B. Regulates current by converting AC to DC
• C. Stores energy in an electric field
• D. Stores energy in a magnetic field

Answer: (D)

An inductor’s function is to store energy in a magnetic field created by current flowing through a coil. The energy stored grows with the current and the inductance, described by W = 1/2 L I^2, and when the current tries to change, the magnetic field resists that change by producing a back emf. This magnetic-field energy storage is what lets inductors smooth out current and influence alternating signals. It’s different from a capacitor, which stores energy in an electric field between plates, and from components that convert AC to DC or claim lossless transmission.

An inductor’s function is to store energy in a magnetic field created by current flowing through a coil. The energy stored grows with the current and the inductance, described by W = 1/2 L I^2, and when the current tries to change, the magnetic field resists that change by producing a back emf. This magnetic-field energy storage is what lets inductors smooth out current and influence alternating signals. It’s different from a capacitor, which stores energy in an electric field between plates, and from components that convert AC to DC or claim lossless transmission.