Question

Differentiate between bar magnet and electromagnet.

Answer 1

Hint The basic difference between them is that a bar magnet is a permanent magnet whereas an electromagnet is a temporary magnet. An electromagnet is formed when an electric current is passed through wires wound around soft metalcore. An electromagnet loses its magnetism once the current flow is stopped.

Complete Step by step solution
Following are the differences between a bar magnet and an electromagnet-

BAR MAGNET	ELECTROMAGNET
A bar magnet is a permanent magnet.	An electromagnet is a temporary magnet.
The magnetism is caused by electron spins. These electrons spin in a particular orientation around the nucleus of ferromagnetic material and cause magnetism.	The magnetism is caused by passing electricity through a conductor and winding it around a core, to align the electrons in a proper orientation.
The strength of the magnetic field produced by a bar magnet is constant.	The strength of the magnetic field produced by an electromagnetic can be varied, depending on the current that passes through the winding or the number of turns.
The polarity of a bar magnet cannot be changed.	The polarity of an electromagnet can be changed by reversing the direction of the current or the winding.
Magnetically hard iron/steel is used to manufacture a bar magnet because once magnetized, it can retain the magnetic property by itself. This property is called ‘remanence’.	A soft iron core is used in the electromagnets, ‘soft’ means that this material gets magnetized and demagnetized easily, which allows the electromagnet to be turned on and off easily.
Examples of permanent magnets include bar magnets, horseshoe magnets, disc magnets, etc.	Examples of electromagnets include solenoid and toroid.

Note A ferromagnetic material can be converted into a permanent magnet if it is kept under a constant magnetic field for a long period. Thus, if instead of a soft iron core, we used a magnetically hardcore (ferromagnetic material), the magnetic properties are retained even after the current flow is stopped.