An electromagnet is defined as what?

• A. A temporary magnet that needs electrical current to produce a magnetic field.
• B. A permanent magnet that does not require current.
• C. A device that measures resistance.
• D. A coil used for wireless power.

Answer: (A)

An electromagnet is a magnet whose magnetic field is produced by electric current flowing through a coil. The current creates the magnetic field, and wrapping the coil around a ferromagnetic core concentrates and strengthens that field. Because the magnetism exists only while the current flows, the magnet is temporary and can be turned on, off, or adjusted by changing the current. This distinguishes it from a permanent magnet, which stays magnetized without any current. It isn’t a device for measuring resistance, and while coils can be used in wireless power setups, the defining feature here is the current-driven magnetic field.