Question

select the correct answer. an electromagnet is a device in which moving electric charges (current) in a coil of wire create a magnet. whats one advantage of using electromagnets in devices? a. electromagnets have a strong, constant magnetic field. b. electromagnets are more powerful than permanent magnets. c. electromagnets dont need a source of electricity to work. d. electromagnets can easily be turned on and off.

Explanation:

Electromagnets' magnetism depends on electric - current flow. When current is on, there is magnetism; when off, there is none. This on - off control is a key advantage. Option A is wrong as their magnetic field is not constant. Option B is incorrect as it's not always true they are more powerful. Option C is false since they need electricity.

Answer:

D. Electromagnets can easily be turned on and off.