Electromagnetism is a branch of physics that deals with the electromagnetic force that occurs between electrically charged particles. The electromagnetic force is one of the four fundamental forces and exhibits electromagnetic fields such as magnetic fields, electric fields, and light.
You can create a simple electromagnet by winding a coil of wire around an iron bar and passing a current through this wire.
Since the electromagnet behaves like a magnet, it also has a magnetic field around it. It can be represented by drawing imaginary magnetic lines of force or magnetic field lines. These lines are in the form of concentric circles around the straight current-carrying conductor, with its centre at the axis of the conductor.
The strength of the magnetic field created depends on the current through the conductor. The direction of these field lines around a conductor can be determined by using Maxwell’s right-hand grip rule or the right-handed corkscrew rule.
The magnetic effect of the electric current is used in much electrical equipment such as electric motors, ammeters, electromagnets, loudspeakers etc.
A few concepts related to this chapter are oersted’s experiment on the magnetic effect of electric current, magnetic field and field lines due to current in a straight wire, the rule to find the direction of the magnetic field, magnetic field due to current in a loop (or circular coil), magnetic field due to a current-carrying cylindrical coil (or solenoid), electromagnet, permanent magnet, advantages of an electromagnet over a permanent magnet, uses of the electromagnet, force on a current-carrying conductor in a magnetic field, simple d.c. Motor, electromagnetic induction, Faraday’s laws of electromagnetic induction, a.c. Generator, frequency of a.c. in household supplies, the distinction between an a.c. Generator and d.c. Motor, transformer.