Key Differences Between Magnetic North and South Poles
The ends of the magnet are known as the poles of the magnets. One side end is known as the North Pole and the other side of the magnet is known as the South Pole. If we take two magnets and one magnet's south side is kept within distance of the north side of another magnet, then both will get attached. This property is known as the property of attraction. And if we place the magnets in the same direction, then both will become apart from each other. This property of magnet is known as the property of repulsion. We can conclude from this that opposite poles attract each other while similar does repulsion.
Magnetic Field Lines
The influence of magnetic forces in a region is described by magnetic field lines. It’s a visual used to depict and understand magnetic field lines. At a regional position they describe the direction of magnetic fields in monopoles.
Though monopoles do not exist in nature so we describe field lines using different methods. One of them is the close connection between both the monopoles of the magnets and electric charges. Few conventions which we have adopted regarding the field lines are: that the field lines enter from the South Pole and get out from the North Pole of the magnet.
In principle, every position at the space field lines can be calculated. But in the visual medium it’s hard to represent. Therefore to indicate the field strength we use density of field lines.
Monopoles: theoretical objects which have either north or south poles are known as the monopoles. Another way to analyse these poles are by magnetic charges, analogous to protons and electrons. As their existence is disputed so they can be artificially synthesized. It should be noted that electrostatic phenomenon is reduced by monopoles. The field lines converge at the south pole and emerge out of north poles.
Properties of Magnetic Field Lines
Magnetic field lines depict the direction of magnetic force. Discussing some of the properties of magnetic field lines. Magnetic field lines always form closed loops. These field lines originate from the north pole and end at the south pole by convention. The direction inside the magnet inversely appears to move from south pole to north of a bar magnet. The field lines move or bulge out when it’s moving from an area of higher permeability to an area of low permeability. Each of these lines contain the same strength. They never cross each other.
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Direction of Magnetic Field Lines
Magnetic field lines are the lines which show the direction of magnetic force.
In a bar magnet if there are two poles one designated as the north and the other as the south, the magnetic field lines make a loop and enter from the south and get outside from the north direction. In a monopole magnet the field line emerges from the north pole and converges in the south pole. If we isolate monopoles magnets in nature they will undergo similar interactions which are in an electric field. The electric field of charges and magnetic fields of monopoles will behave in a similar manner and a similar electric field would be observed in magnetic monopoles. The elegance of this idea exists no matter whether poles exist or not.
Coulomb type law is seen when one claims the definition of magnetic charge analogous to electric charge.
North and South Poles
A magnet consists of two poles of magnets which are designated as the south pole and the north pole. There are many magnets but primarily we will discuss the bar magnets. What we have observed above are the two poles of the magnets north and south poles. If we freely suspend a magnet it will always point out in the north direction. This property is known as the north pole of magnet.
Just opposite to the north lies the south end or south pole. If we see a compass which is itself a magnet and it always points in the north direction, except in the case of a strong magnet. In that case the pointing of the compass is different . The magnet field causes magnetic force which further causes attraction or repulsion.
On the earth's northern hemisphere the north magnetic pole is the wandering point at which earth's magnetic field points downwards.
This is the reason why the compass needle points in the north direction when freely suspended. But as we move towards the north magnetic pole it will point horizontally or in a straight direction.
According to the flux lobe elongation and magnetic flux the north magnetic poles move. Its counterpart south is in the south magnetic pole. The north and south poles are not antipodal as our earth is not symmetrical.
FAQs on Poles of Magnets: Definition, Properties & Applications
1. What are the poles of a magnet?
The poles of a magnet are the specific regions, typically near the ends, where the magnetic force is the strongest. Every magnet has two poles: a North pole and a South pole. These are the points from which the magnetic field lines are considered to emerge and into which they enter.
2. What are the key properties related to the poles of a magnet?
The poles of a magnet have several fundamental properties that are important for the CBSE/NCERT curriculum. These include:
- Poles exist in pairs: You can never have an isolated North pole or South pole. If you break a magnet, you get two smaller magnets, each with its own North and South pole.
- Attraction and Repulsion: Like poles repel each other (e.g., North repels North), while unlike poles attract each other (e.g., North attracts South).
- Directive Property: When a magnet is suspended so it can move freely, its North pole points towards the Earth's geographic North, and its South pole points towards the Earth's geographic South.
3. Where are the poles located on different types of magnets?
The poles are located at the points of maximum magnetic strength, and their position depends on the magnet's shape. For a simple bar magnet, the poles are located very near its two ends. In a horseshoe magnet, the poles are at the two open ends of the 'U' shape. For a disc or coin magnet, the poles are typically on the two opposite flat faces.
4. How can you identify the North and South poles of an unmarked magnet?
The most reliable method is to suspend the magnet from its centre with a string so it can rotate freely. The end of the magnet that points towards the Earth's geographic North is the magnet's North-seeking pole (or simply, North pole). The opposite end is the South pole. Alternatively, you can use a known magnet or a compass; the North pole of the compass will be attracted to the South pole of the unmarked magnet.
5. Why is the magnetic force strongest at the poles of a magnet?
The magnetic force is strongest at the poles because this is where the magnetic field lines are most concentrated. These invisible lines represent the magnetic field. They emerge from the North pole and re-enter at the South pole. At the ends (the poles), these lines are bunched tightly together, indicating a strong, dense magnetic field and thus the strongest force. In the middle of the magnet, the lines are spread farther apart, resulting in a weaker field.
6. Is a magnet's North pole positive and its South pole negative?
This is a common misconception. Magnetic poles are not related to electric charges. Unlike positive and negative electric charges, North and South poles cannot be isolated from each other. The terms 'North' and 'South' refer to the directionality of the magnetic field, not an electrical state. By convention, magnetic field lines are defined as exiting from the North pole and entering the South pole.
7. What would happen if you cut a bar magnet in half at its centre?
If you cut a bar magnet in half, you do not get a separate North pole and a separate South pole. Instead, you create two new, smaller magnets. Each new piece will instantly have its own North and South pole. This demonstrates a fundamental law of magnetism: magnetic poles always exist in pairs, and magnetic monopoles (single, isolated poles) have never been observed to exist in nature.
8. What is the real difference between a magnet's North pole and South pole?
Beyond being opposites that attract, the fundamental difference lies in their role within the magnetic field. By international convention:
- The North pole is defined as the end from which the magnetic field lines emerge or point away from the magnet into the surrounding space.
- The South pole is defined as the end into which the magnetic field lines enter or point towards the magnet from the surrounding space.
This directional convention is what truly defines their distinct properties and interactions.
