What is an electromagnet ? State the principle on which it works. Draw a circuit diagram to show how a soft iron piece can be transformed into an electromagnet . Write uses of electromagnet.

Explanation

Electromagnet : An electrongnet is a magnet consisting of a long coil of insulated copper wire wound around a soft iron core in the from of a rod. It is magnetised only when an electric current is passed through the coil .
OR
An electrongnet is temporary strong magnet and is just a solenoid with its winding on a soft iron core .
The working of an electrognet is based on the magnetic effect of electric current .

A strong magnetic field produced inside a current - carrying solenoid can be used to magnetise a piece of magnetic material like soft iron , by placing it inside the coil / solenoid (figure 13.17) . The magnet so formed is called an electromagnet.
An electromagnet acquires the magnetic properties only when an electric current is passed through the solenoid .
Once the current is switched off , it almost loses its magnetic property as the retentivity ( the ability to retain magnetism) of soft iron is very low .
The strength of the electromagnet depends on :
(i) The number of turns per unit length n of the solenoid .
(ii) The current I through the solenoid .
Uses of electromagnets :
(1) Electromagnets are used in electrical devices such as an electric bell , an electric fan , telegraph , an electric train , an electric motor, genertor etc.
(2) They are used for lifting and transporting large masses of iron in the from of girders .
(3) They are used in medical paractice for removing pieces of iron from wounds .