Electromagnetism

There are very many objects in everyday use that make use of electromagnetism, such as bells, electric motors, loudspeakers, audio and videotapes and computer disks. All electric currents produce a magnetic field albeit a very small force. This effect can be increased by wrapping a coil of insulated wire around an iron core, such as a nail. When a current is passed through the iron nail, it becomes magnetized and a controllable magnet has been created since when the current is turned off the nail will lose its magnetic properties. Increasing the number of coils of wire around the iron core, or increasing the current being passed through the wire, can increase the strength of an electromagnet. Electromagnetism can be useful (e.g. in a car-breaker’s yard) as the magnetism is controllable and can be switched on and off.