Why is it impossible to get 'N' and 'S' poles on their own?
1 Answer
Because North pole or South pole of a magnet is not a physical quantity. It is a pre-defined sense of direction.
Explanation:
Let us understand why magnetism exists.
It is one of the fundamental attributes/properties of electrons that it has magnetic dipole moment. This means that it behaves like a small magnet.
This dipole moment comes from another fundamental property of the electron that it spins. Due to quantum mechanical nature of this spin, the spin or the magnetic dipole moment can exist only in two states. The magnet field can either be in Up direction or in the down direction. One is at liberty to define "up direction". Once this has been defined down gets defined automatically.
In a piece of matter when these small magnets align in a particular direction all aligned magnetic fields add together to create a much larger macroscopic field. We see, therefore, that even smallest magnet has two directions associated with it, which are inseparable.
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Dirac in 1931 made a theoretical observation that a mono-pole magnet should be observable. We also know that such theories are only mathematical models to explain some physical phenomena.
However, despite systematic searches since 1931 till date, magnetic mono-poles have not been reported as observed, and could very well may not physically exist.
