Hello, fellows, I hope you all are doing great. In today’s tutorial, we will discuss What is Electromagnetism. Initially, electricity and magnetism were known 2 different aspects of physics. This concept was changed by the theory of Maxwell about the electricity and magnetism in 1873, that says the interaction among positive and negative charges behaves like a single force. There were 4 different factors were found by the interactions of the positive and negative charges. In first fact, Maxwell found that the charge either positive or negative attract or repel with a force that is inversely proportional to the square of the distance among charges. In second fact, he said that north and south poles have attraction and repulsion like the charges. In the third fact, he said that current passing through any conductor produces field around it. And in the fourth fact, he described that if we move conductor in a magnetic field there will be an emf induced in that conductor. In today's post, we will relate all these factors and study their effect on the magnetism. So let's get started with the What is Electromagnetism.

#### What is Electromagnetism

• The branch of the physics that deals with the electromagnetic force and describes the relationship between charges & poles is known as the electromagnetism.
• The emf (electromagnetic force) is caused by the two fields first one is electrical field and the second one is magnetic field.
• As electromagnetism describes the emf so it is also known as the Lorentz force (it describes the collective effect of the electric and magnetic forces on the charges).
• The emf helps to study the internal structure and properties of any substance that exists in our environment.
• The nucleus of different atoms is connected with their valance band electrons by the emf. Due to the emf, different bonds are created among the atom and they create molecules.
• The emf describes the chemical relationship among the electrons of different atoms.
• There are many ways to describe the emf mathematically. In classical electrodynamics (it is a branch of physics that describes the relationship among the charge and current by Newtonian model) the electric field is explained as the electrical potential.
• Faraday's Law describes that the magnetic field is produced by the phenomena of magnetic induction.
• The theoretical explanation of the electromagnetism was given by Einstein in 1905, in the form of the special theory of relativity (this theory describes the relationship between space and time).

#### Magnetic Field around a Conductor

• When the current is passing through the conductive wire then the field is produced around the conductor in the shape of a circle. The strength of the field is stronger near to the conductor and it becomes weaker as it moves away from the conductor.
• The direction of the magnetic field can be found by the current flowing in the conductor. In the given diagram, you can see the direction of the field and the current.
• The easiest way to find the direction of we take an example of the screw that is inserted in the piece of the paper.
• Then the screw is inserted in the paper its direction of the rotation is clockwise and after the complete insertion of the screw, the only part of the screw out of the paper is its head.
• If the screw has the pozidriv type head configuration, the cross on the head of head will be shown that indicates the direction of the current flowing into the page and away from us.
• Similarly the removal of the screw from the page in counter-clockwise. As current goes from the top of screw towards the bottom of the paper, if we see from the other side of page we see only a point that tells us that current moving towards us.
• After finding the direction of the current we now, know how we can find the direction of the field. For this, we study the right-hand screw action.
Right Hand Screw Action
• The magnetic field shows the availability of the north (N) and the south (S) pole, to show the north and south poles of the current-carrying conductor we use alphabetical letters S and N.
• If we join the arrowheads to without arrowhead points of the N and S, then we get the direction of the magnetic field. It is shown in the given diagram.
Left Hand Rule of Electromagnetism
• There is another famous technique to find the direction of the current and magnetic field, it is the left-hand rule (L.H.R).
• The magnetic field starts from the north pole and ends at the south pole.
• If we grasp the conductor in the left hand in such a way that the figures show the direction of the current then the thumb will tell about the direction of the magnetic field.
• If the current flowing in the conductor changes its direction than we will grasp the conductor from the other side and find the direction of the field.

#### Example of the Electromagnetism

• The normal loudspeaker that is used television, in different seminars is a suitable example of the electromagnetism.
• To see the working of such devices that follows the phenomena of the electromagnetism, we discuss the given figure.
• For the conversion of the electric signal, the loudspeaker was introduced, in the figure you can see there is a coil is wound on the conductor when a permanent comes to this coil it produces a magnetic field in the coil and it works as an electromagnet.
•  The field of the electromagnet gets repulsion by the field of the permanent magnet. Due to the interaction of these field vibrations are produced, these vibrations amplified by the conical shape assembly and then sound produced in the speaker.
• It is the phenomena that show the working of the electromagnetism in the loudspeaker.
•  The newly formed magnetic field is repelled by the permanent magnetic field resulting in the vibrations. These vibrations are amplified by the cone-like structure causing the sound. This is how speakers work based on electromagnetism.

#### Applications of the Electromagnetism

• These are some applications of the Electromagnetism.
• This phenomenon is used in electrical motors to develop a magnetic field.
• The working of the CAT scan machine is based on the electromagnetism, this machine is used in the hospital to diagnose the disease.
It is the complete article on the electromagnetism if you have any question ask in comments. Thanks for reading. Take care until the next tutorial.