Which component is a coil that produces a magnetic field when current flows through its windings?

Which component is a coil that produces a magnetic field when current flows through its windings?

• A. Hydrometer
• B. Ground
• C. Inductance
• D. Electromagnet

Answer: (D)

A coil that carries current creates a magnetic field around its windings, and when that coil is built to generate magnetic force for a purpose—such as pulling a plunger or attracting metal with a core to intensify the field—it’s called an electromagnet. The field strength grows with more turns and a ferromagnetic core, which concentrates the magnetic flux. Inductance, by contrast, is a property of a coil that describes how it resists changes in current and stores energy in the magnetic field; it’s not the device that produces the field itself. The other options don’t involve generating a magnetic field.

A coil that carries current creates a magnetic field around its windings, and when that coil is built to generate magnetic force for a purpose—such as pulling a plunger or attracting metal with a core to intensify the field—it’s called an electromagnet. The field strength grows with more turns and a ferromagnetic core, which concentrates the magnetic flux. Inductance, by contrast, is a property of a coil that describes how it resists changes in current and stores energy in the magnetic field; it’s not the device that produces the field itself. The other options don’t involve generating a magnetic field.