What are electromagnets?

Electromagnets are used when very strong magnets are needed. Electromagnets are made by placing a metal core (usually an iron alloy) in a coil of wire that carries an electric current. The electricity in the coil creates a magnetic field. The strength of the electromagnet depends on the strength of the electric current and the number of coils. Its polarity depends on the direction of the current flow. While the current is flowing, the core behaves like a magnet, but as soon as the current stops, the magnetic properties are lost. Electric motors, televisions, maglev trains, telephones, computers and many other modern devices use electromagnets.