ELECTROMAGNET

A solenoid with ferromagnetic core is called an electromagnet. An electromagnet is a type of magnet in which the magnetic field is produced by the flow of electric current.
The magnetic field of an electromagnetic field is produced by the current in the wire and the magnetized core. An electromagnet is a strong magnet that can be turned ON and OFF.
An electromagnet is simply a coil of wire. It is usually wound around an iron core. However, it could be wound around an air core, in which case it is called a solenoid. When connected to a DC voltage or current source, the electromagnet becomes energized, creating a magnetic field just like a permanent magnet. The magnetic flux density is proportional to the magnitude of the current flowing in the wire of the electromagnet. The polarity of the electromagnet is determined by the direction the current. The north pole of the electromagnet is determined by using your right hand. Wrap your fingers around the coil in the same direction as the current is flowing (conventional current flows from + to -). The direction your thumb is pointing is the direction of the magnetic field, so north would come out of the electromagnet in the direction of your thumb. DC electromagnets are principally used to pick up or hold objects.