Question

What is electromagnet? Draw a circuit diagram to show how a soft iron piece can be transformed into an electromagnet.

Answer 1

Hint: An electromagnet is a non-permanent magnet formed when the current passes through a solenoid and a material like the soft iron core gets magnetized. The magnetic properties are present only when the current passes through the insulated copper wire surrounding the solenoid.

Complete step by step solution:
Electromagnet is a magnet where the magnetic field is produced by electric current. It is known that when a current passes through a coil, it generates a magnetic field around it. This property of electromagnetism is applied in electromagnetics.
To create an solenoid, an insulated copper wire is used, this wire is wound around a soft iron core and both the ends of this wire are connected to a battery, and the switch is closed. When the current flows through the wire loop, it generates a small magnetic field around it. Many such loops are formed when the wire is wound around the metal core. Thus the intensity of the magnetic field is increased .All the magnetic field lines created by the wire loops pass through the soft iron core. Thus it gets magnetized as well, this results in formation of an electromagnet, or a solenoid.
This diagram shows how a soft iron piece can be transformed into an electromagnet-

The iron core behaves like a bar magnet, and has a North pole where the magnetic field lines come out and a south pole where the field lines go back into the core.


Note: The direction of winding of the insulated copper wire is given by the right hand thumb rule. The polarity of the magnet can be reversed by reversing the direction of current. This is either done by changing the polarity of the magnet or by changing the direction of winding, from clockwise to anticlockwise.