Question

Name the device that uses an electromagnet

• A. Electric bell
• B. Barometer
• C. Lactometer
• D. All the above

Answer 1

The correct option is A Electric bell

An electromagnet is a type of magnet in which the magnetic field is produced by an electric current. The magnetic field disappears when the current is turned off. Electromagnets usually consist of a large number of closely spaced turns of wire that create the magnetic field. The wire turns are often wound around a magnetic core made from a ferromagnetic or ferrimagnetic material such as iron; the magnetic core concentrates the magnetic flux and makes a more powerful magnet.
The main advantage of an electromagnet over a permanent magnet is that the magnetic field can be quickly changed by controlling the amount of electric current in the winding. However, unlike a permanent magnet that needs no power, an electromagnet requires a continuous supply of electrical energy to maintain a magnetic field.
Electromagnets are widely used as components of electrical devices such as motors, generators, loudspeakers, hard disks, MRI machines, scientific instruments, etc.