If a few turns of wire are wrapped around a core of soft iron and a current is passed through the wire, what is created?

When wire is wrapped around a core of soft iron and an electric current passes through it, an electro-magnet is created. This phenomenon occurs due to the magnetic field generated by the electric current flowing through the wire. The soft iron core enhances the magnetic field, making the electromagnet significantly stronger than the magnetic field produced by the wire alone.

Electro-magnets are widely used in various applications, such as in motors, relays, and magnetic locks, due to their ability to be turned on and off by controlling the current. The core's property of being made from soft iron is key, as soft iron has low retentivity, meaning it loses its magnetism quickly once the current stops flowing, allowing for rapid on/off functionality.