Question

Explain why an electromagnet is called a temporary magnet.

Answer 1

Hint : The working of the electromagnet and the properties of the substances used in the building of an electromagnet is behind the reason why an electromagnet is called a temporary magnet. By going through these points we can get the answer.

Complete step by step answer
Electromagnets are devices that use electricity to create a magnetic field. These consist of coils of wire which behave like bar magnets with a distinct north and south pole when an electrical current passes through the coil. It behaves almost like a natural magnet and has north and south poles that attract and repel north and south poles respectively of natural magnets. It can attract certain materials. Copper wire, a nonmagnetic substance, is wound around the iron core in coils. While iron can be made into a permanent magnet, the iron core of an electromagnet is not a magnet. All of the materials an electromagnet is made of are nonmagnetic.
A permanent magnet is a magnet that retains its magnetism. In materials like magnetite, iron, nickel, or neodymium, the magnetic fields can line up and act with one another, which give the object a powerful magnetic field.
Temporary magnets only retain their magnetism while near a permanent magnetic field or electric current. Thus, they require an external force to remain in its magnetised state.
When the battery is connected to the coil, current flows through it. In this way a magnetic field is generated. Iron has a high magnetic permeability, which enables it to reinforce the magnetic field generated by the wire. However, as soon as the power from the battery stops, the current stops, and this means that the magnetic field vanishes. This is the reason that electromagnets are temporary magnets.
Thus, electromagnet is called a temporary magnet.

Note
The direction of the magnetic field through a coil of wire can be found from the right-hand rule. Electromagnets find broad application in motors and generators, transformers, relays, electric bells and buzzers, loudspeakers and headphones.