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:
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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:
The Planet Earth has a magnetic north pole in which the north hand of the compass points downwards.
It also has a magnetic south pole in which the south hand of the compass points downward.
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.
FAQs on Magnetic Pole
1. What defines a magnetic pole?
A magnetic pole is a specific point at or near the end of a magnet where the magnetic force appears to be most concentrated. Every magnet has two poles, a North pole and a South pole. These poles are regions of maximum magnetic strength and are fundamental to how magnets interact with each other and with magnetic fields.
2. What are the fundamental properties of magnetic poles?
The fundamental properties of magnetic poles are:
- Like poles repel: The North pole of one magnet will repel the North pole of another. Similarly, two South poles will repel each other.
- Unlike poles attract: The North pole of a magnet will attract the South pole of another magnet.
- Poles always exist in pairs: It is impossible to isolate a single North or South pole. If you break a magnet, each piece will form a new magnet with its own North and South pole.
3. How are the North and South poles of a magnet identified?
The poles of a magnet are identified using the Earth's magnetic field. If a bar magnet is freely suspended, it will align itself in the geographic North-South direction. The end of the magnet that points towards the Earth's geographic North is called the North-seeking pole (or simply the North pole). The end that points towards the Earth's geographic South is the South-seeking pole (or South pole).
4. Why can't a magnetic monopole (an isolated North or South pole) exist?
A magnetic monopole cannot exist because magnetic field lines are always closed loops. They originate from the North pole and terminate at the South pole, continuing the loop *inside* the magnet. Unlike electric charges, which can exist as isolated positive or negative points, magnetic poles are intrinsically linked. This concept is a fundamental principle of magnetism, described by Gauss's law for magnetism, which states that the net magnetic flux through any closed surface is zero.
5. How is the strength of a magnetic pole measured?
The strength of a magnetic pole, known as pole strength (m), is a measure of its ability to attract or repel other magnetic poles. It is a scalar quantity, and its SI unit is the ampere-meter (A m). The force between two magnetic poles is described by Coulomb's law in magnetism, which relates the force to the product of the pole strengths and the inverse square of the distance between them.
6. What is the difference between Earth's geographic poles and its magnetic poles?
The Earth's geographic and magnetic poles are distinct concepts:
- Geographic Poles: These are the fixed points (North and South) that define the axis around which the Earth spins.
- Magnetic Poles: These are the points where the Earth's magnetic field lines are vertical. The 'magnetic North Pole' is actually the south pole of Earth's internal magnet, which is why a compass's North pole is attracted to it. These poles wander over time and are not aligned with the geographic poles.
7. How are magnetic poles different from electric charges?
Magnetic poles and electric charges have key differences, despite both having 'like-repels-like' and 'unlike-attracts-unlike' properties:
- Existence in Pairs: Magnetic poles always exist in pairs (a North and a South pole). You cannot have an isolated magnetic pole. Electric charges, however, can exist as isolated positive (+) or negative (-) monopoles.
- Source: Magnetism, and therefore magnetic poles, arises from the movement and spin of electric charges (i.e., electric currents). Electric fields, on the other hand, can be created by stationary electric charges.
8. Is the North pole of a magnet positive or negative?
The North pole of a magnet is neither positive nor negative. The terms 'positive' and 'negative' are reserved for electric charges. Assigning these labels to magnetic poles is a common misconception. While the North pole is where magnetic field lines conventionally emerge (analogous to positive charges), the underlying physics is different, as magnetism is generated by moving charges, not static 'magnetic charges'.
9. If you break a bar magnet in half, do you create two separate magnetic poles?
No, breaking a bar magnet in half does not create separate, isolated poles. Instead, you create two new, smaller magnets, each complete with its own North and South pole. At the point of the break, new opposite poles are instantly formed on the broken faces. This demonstrates the fundamental principle that magnetic monopoles do not exist in nature.
10. What are some real-world examples that rely on the properties of magnetic poles?
The properties of magnetic poles are crucial in many everyday technologies and natural phenomena:
- Compasses: A magnetic compass needle aligns with Earth's magnetic poles to indicate direction.
- Electric Motors and Generators: These devices use the forces of attraction and repulsion between the poles of magnets and electromagnets to function.
- Data Storage: Hard drives and magnetic tapes use tiny magnetic domains, each with North and South poles, to store binary data.
- Maglev Trains: These trains use the powerful repulsive force between like poles of electromagnets on the train and the track to levitate and move.
