Home Basic Electronics What is electromagnetism? Concept of electromagnetism

What is electromagnetism? Concept of electromagnetism

What is Electromagnetism?

The permanent magnet can produce a good and very strong magnetic field. But in some applications, the magnetic field is too week and we need to increase the strength of the magnetic field. Therefore to increase the strength of the magnetic field we need to use electricity.


By using coils of wire you can produce the magnetic field. As shown in the above figure wound coil of wire around an iron nail and connect it with a battery which produces a magnetic field. strong electromagnets used in many different types of electrical applications. This coils of wire produce a relationship between magnetism and electricity and magnetism gives us another form of magnetism which called Electromagnetism.

Electromagnetism is produced when electric current flows through a simple wire, Which creates a magnetic field in the whole conductor. The magnetic field around the conductor has a definite direction North and south. This north and south poles determined the direction of the electric current flowing through the conductor.

Therefore it is essential to establish a relationship between the current and magnetic field produced around it in the form of the electromagnetism. We observe that when an electric current flows in conductor a circular electromagnetic field produce and forming complete loops that do not cross around the length of the conductor.

The direction of the magnetic field is governed by the current flowing through the conductor. Magnetic field near the center of the conductor is stronger.

Magnetic Field around a Conductor

To determine the direction of the magnetic field let’s take one example when you screwing a wood screw into a sheet of paper. As the screw go deeper into the paper in a clockwise direction and the only screw is visible above the sheet of paper. Screw head indicates the current flowing.
When you remove the screw in an anticlockwise direction which shows that current enters from the top and leaves the underside of the paper and only the wood screw is visible from the tip. Which is used to indicate the current flowing out of the paper.

The physical action of the screwing in the wood, screw in and out of the paper indicates the direction of the current. and the direction of the rotation of the electromagnetic field is shown below.

The Right Hand Screw Action

A magnetic field can be established in two directions north and south pole which is denoted by capital laters S and N.

Left-hand rule and the right-hand rule also determine the direction of current flow and magnetic flux.

Left-Hand Rule for Conductors
As shown in the above figure the thumb shows the direction of current flow and figure shows the magnetic flux direction this is left-hand thumb rule.

If the direction of the electron flow is reverse left-hand is replace with the right-hand rule. as current is in reverse direction to the magnetic field is also generated in the reversed direction.

Electromagnetism around a Loop

The current passing through the parallel conductors of the loop is in the opposite direction. This result in a magnetic field is in the same direction to each other.


And lines of force generated in conductor oppose each other in the space between the two conductors. However, there is some distortion in the magnetic field at the middle junction. When two like fields produces in conductor they try to repel away from each other.

Magnetic field is strongest in the middle of the conductors. The intensity of the produce magnetic field is proportional to the distance from the conductor and the amount of the current flowing through it. The magnetic field present around a straight wire is very weak. However in the loop from the magnetic field is stronger than the straight wire.

Every length of wire affected by electromagnetism. We can increase the strength of the magnetic field by forming the length of wire into several coil form.


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