When a bar magnet is cut into two halves repel each other. Why? What becomes of the original north and south poles of that magnet??
When a bar magnet is cut into two halves, each half becomes a separate magnet with its own set of poles.
To understand why the two halves repel each other, we need to look at the properties of magnets at the atomic level. Magnets are made up of tiny regions called magnetic domains, which are made up of atoms with aligned magnetic fields. In an unmagnetized piece of iron, these domains are randomly oriented, resulting in a net magnetic field of zero. However, when a magnetizing force (such as another magnet) is applied, these domains align to create a strong magnetic field.
In a bar magnet, the magnetic domains are aligned in such a way that one end becomes the North Pole, and the other end becomes the South Pole. When the magnet is cut in half, the domains in each half try to realign themselves to maintain a net magnetic field. As a result, one half becomes a new magnet with a North Pole, while the other half becomes a new magnet with a South Pole.
Since like magnetic poles repel each other, the two halves of the cut bar magnet will repel each other when brought close together. This repulsion occurs because the North Pole of one half is attracted to the South Pole of the other half, while the North Pole of one half repels the North Pole of the other half.