Electromagnetism -Definition,History and Application

Electromagnetism Definition

Electromagnetism is the branch of physics in which we study the relationship between the electricity and magnetism, that is produced by the electromagnetic force.

Electromagnetism is the physical interaction, occurs between the particles that are electrically charged.

The electromagnetic field is the composition of the electric field and magnetic field, which produces electromagnetic force. It is responsible for electromagnetic radiation.

For example, light is one of the examples of electromagnetic radiation.

For determining the internal properties and internal work of most objects, that we deal with in our daily life, we use the electromagnetic force.

While studying electromagnetism we should must familiar with these terms:

Electric current

Electric current is the rate of change of electric charge.

We can find current by using the formula:


Where I am current, Q is charge and t is time.

The SI unit of electric current is ampere denoted as A.

Electric charge

Electric charge is the physical property of matter that experienced a force when it was placed in a magnetic field.

There are two types of electric charges, positive charges, and negative charges. The same charges repel each other while opposite charges attract each other.

The charge can find out by:

q= CV

Where q is a charge, C is the capacitance of a circuit and V is the voltage.

The SI unit of electric charge is the coulomb.

Magnetic flux

Magnetic flux is the measurement of the total magnetic field that is present in the given area.

SI unit of magnetic flux is Weber.


In an electrical circuit, the measurement of the opposition to the flow of current is known as resistance.

SI unit of resistance is the ohm.


Capacitance is the measurement of the ability of a capacitor to store the electric potential. It depends on the charge and voltage of the circuit.

The SI unit of capacitance is farad.

Also read:

History of Electromagnetism

Initially, it was considered that electricity and magnetism were two separate forces.

This concept was changed when James Clerk Maxwell published A Treatise on Electricity and Magnetism. In which he wrote about the interaction between positive and negative charges, and show them into one force. He concluded four results from his experiment.

These results are:

  1. Same charges repel each other while opposite charges attract each other, and the force between them is inversely proportional to the square of the distance between them.
  2. Magnetic poles, north and south poles, behave the same as charges. The same poles repel but the opposite poles attract each other.
  3. When we pass electric current inside the wire, it creates a corresponding circumferential magnetic field at the outer side of the wire.
  4. When we bring the magnet near to the electric current, the direction of the current changes with the movement of the magnet.

Hans Christan Orsted, was a teacher, while preparing his lecture he noticed that when switched on and off, the compass needle deflect from the north pole.

From here he carefully observed and confirmed the relation between electric and magnetic field.

Oster was not the only one who discovered the relation between electricity and magnetism, many other scientists also observed and finally considered both as the same force that today we call electromagnetism.

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The electromagnetic force is a fundamental force:

There are four known fundamental forces. That is a strong nuclear force, weak nuclear force,  gravitational force, and electromagnetic force.

All the forces involved in the interaction between atoms are explained by the electromagnetic force, which is the interaction between nuclei-bounded electrons of the atom.

By electromagnetic force, we can easily study the momentum of these particles that they carry during their movement.

Applications of electromagnetism

Electromagnetism is at the top in the world of technology. There are so many technological applications of electromagnetism.

  1. In the field of medicines, most of the technologies are introduced that works on electromagnetism. MRI scanners, that are used to diagnose diseases and take images of the inner part of the human body, lly gigantic electromagnets, that are controlled by turning electricity flow up and down. X-rays also works on the principles of electromagnetism.
  2. Many household appliances such as lighting, kitchen appliances, air conditioners, cooling fans, electric motors, and electric bells are the applications of electromagnetism.
  3. Televisions, radios also contained electromagnetic attached to magnetic flux, produced by a permanent magnet.
  4. Our communication system also works on electromagnetism. The sound of our mobile phones converts into electromagnet waves while we talk with someone.

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