Which device becomes magnetized when current passes through its coil?

Which device becomes magnetized when current passes through its coil?

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

Answer: (B)

When current flows through a coil, it creates a magnetic field around the winding. If that coil is part of a device designed to use that field to attract or hold metal, the result is an electromagnet. The core (often iron) concentrates the field, making the device magnetized and able to exert magnetic force. Hydrometers, ground, and inductors don’t become magnets in the same practical sense: a hydrometer is for measuring liquid density, ground is a safety/return path, and an inductor stores energy in a magnetic field but isn’t a magnet designed to produce force on objects.

When current flows through a coil, it creates a magnetic field around the winding. If that coil is part of a device designed to use that field to attract or hold metal, the result is an electromagnet. The core (often iron) concentrates the field, making the device magnetized and able to exert magnetic force. Hydrometers, ground, and inductors don’t become magnets in the same practical sense: a hydrometer is for measuring liquid density, ground is a safety/return path, and an inductor stores energy in a magnetic field but isn’t a magnet designed to produce force on objects.