Steel Core and Electric Current in a Coil

When a coil is wound around a steel core and an electric current is passed through the coil, the steel core acts as a permanent magnet.

Electromagnets
An electromagnet is a type of magnet that is created by passing an electric current through a coil of wire. When an electric current flows through a wire, it generates a magnetic field around the wire. By winding the wire into a coil, the magnetic field becomes concentrated and stronger. This coil of wire becomes an electromagnet.

Permanent Magnets
A permanent magnet, on the other hand, is a material that retains its magnetism even when no external magnetic field is present. These magnets are made from materials such as iron, nickel, and cobalt, or alloys of these elements. Permanent magnets have their own magnetic field due to the alignment of the magnetic domains within the material.

Explanation
When a coil is wound around a steel core and an electric current is passed through the coil, the steel core acts as a permanent magnet. This is because the electric current flowing through the coil creates a magnetic field. The steel core, being made of ferromagnetic material, gets magnetized by the magnetic field generated by the coil.

The steel core enhances the magnetic field produced by the coil by providing a path for the magnetic flux. It increases the strength of the magnetic field and concentrates it within the core. This makes the steel core behave like a permanent magnet as long as the electric current is flowing through the coil.

The strength of the magnetic field produced by the coil and the steel core can be increased by increasing the number of turns in the coil, increasing the current flowing through the coil, or using a material with higher magnetic permeability for the core.

In conclusion, when a coil is wound around a steel core and an electric current is passed through the coil, the steel core acts as a permanent magnet. It enhances the magnetic field produced by the coil and retains its magnetism even when the current is turned off.