Which component stores energy in a magnetic field using a coil of wire?

Which component stores energy in a magnetic field using a coil of wire?

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

Answer: (B)

Energy stored in a magnetic field from a coil of wire points to an inductor. When current flows through a coil, it creates a magnetic field around the windings, and energy is stored in that field. The amount of energy is proportional to one-half times the inductance times the current squared (E = 1/2 L I^2). This magnetic storage lets the inductor oppose changes in current, since changing the current would require adding or removing energy from the field. That’s why the coil-of-wire component is the one that stores energy magnetically. A capacitor stores energy in an electric field between plates, not a magnetic field. A resistor dissipates energy as heat and doesn’t store it. A transformer uses magnetic coupling between windings to transfer energy and change voltage, but its purpose isn’t primarily energy storage.

Energy stored in a magnetic field from a coil of wire points to an inductor. When current flows through a coil, it creates a magnetic field around the windings, and energy is stored in that field. The amount of energy is proportional to one-half times the inductance times the current squared (E = 1/2 L I^2). This magnetic storage lets the inductor oppose changes in current, since changing the current would require adding or removing energy from the field.

That’s why the coil-of-wire component is the one that stores energy magnetically. A capacitor stores energy in an electric field between plates, not a magnetic field. A resistor dissipates energy as heat and doesn’t store it. A transformer uses magnetic coupling between windings to transfer energy and change voltage, but its purpose isn’t primarily energy storage.