[Physics Class Notes] on Magnetic Pole Pdf for Exam

A magnet comprises two poles viz: a magnetic north pole and magnetic south pole. A pole that has the strongest magnetic field is the magnetic pole. 

Here, the pole of a magnet is a magnetic monopole, which is a hypothetical elementary particle. 

Suspend a magnet and the place where the magnetic field strength is the strongest is the magnetic pole.

On this page, we will discuss the magnetic field of Earth and the Earth’s magnetic pole with the understanding of the magnetic N-S pole.

What are Magnets?

An object that has the ability to generate a magnetic field around itself is known as a Magnet. A magnet can attract ferrous objects like steel, iron, nickel, and cobalt.

 

History of a Magnet

In the early days, around the period of 600 B.C., the Greeks observed that the naturally occurring element, viz:  ‘lodestone’ attracted iron pieces, and this led a path to the study of magnets. 

In today’s time, magnets are very common as they can even be made artificially (temporary magnets), giving various shapes and sizes.

The best-known example of common magnets that can be seen in our household is the bar magnet. In general terms, a bar magnet is long and rectangular in shape of a uniform cross-section area that attracts pieces of ferrous objects. There are two different poles of a magnet; the magnetic north pole and the magnetic south pole. 

The magnetic compass needle is also a commonly used device that has helped sailors for navigation in the ancient period, and in today’s time as well. 

The needle comprises a small magnet that is free to move horizontally on a fixed point. The two poles of the magnetic compass needle point towards the north and south directions.

The below image shows how a magnet has two poles and the magnetic lines emitting out of the magnet from the magnetic north pole location to the magnetic south pole:

Magnetic North Pole

The north pole of Earth’s magnet is in the poles of Earth. It is a point on the surface of Earth’s Northern Hemisphere at which the magnetic field of Earth vertically points downwards. 

So, if a magnetic compass needle is allowed to rotate around the horizontal axis, it points straight down. 

There is only one magnetic pole location where this occurs, near the Geographic North Pole. The north pole of Earth’s magnet is in the poles of Earth, and it is a related point, is the pole of an ideal dipole model of the magnetic field of Earth that most closely fits the Earth’s actual magnetic field.

Magnetic South Pole

The South Magnetic Pole is the fixed point on the southern hemisphere of the Earth. It is a point where the geomagnetic field lines direct vertically upwards. The Geomagnetic South Pole is a related point or the south pole of an ideal dipole model that most closely fits the Earth’s actual magnetic field.

Earth’s Magnetic Poles

A magnetic pole is a region in which the end of a magnet has the strongest external magnetic field. Magnetic poles of astronomical bodies like the Earth is a special case of magnets, so let’s discuss these:

Magnetic Poles of a Bar Magnet

The bar magnet is an easily available device to visualize the magnetic poles. 

In a bar magnet, the two ends of a permanent magnet are called poles of a magnet or the magnetic poles. The force exerted by a magnet is indicated using curved lines with arrows. 

These magnetic field lines of force along with the magnetic field surrounding the magnet are called magnetic field lines. The arrows on the lines show the direction of a magnetic force, i.e., these lines originate from the North Pole to the South Pole of the magnet.

Now, let’s understand the concept of the magnetic pole in a bar magnet:

When we suspend a bar magnet in the Earth’s magnetic field, it points itself in a north-south direction. 

The north-seeking pole of such a magnet is the magnetic north pole, while the south-seeking pole is called a magnetic south pole. 

We must note that unlike poles of two magnets tend to attract each other while the like poles tend to repel each other.