“Can a magnet lose its magnetic properties?How?
Why ‘repulsion’ and not ‘attraction’ is suggested to be a good test of finding whether a substance is a magnet or not?”
A magnet can lose its magnetism.
A magnetic substance is made a magnet by making the molecules which are individually possessing magnetic properties align in a particular direction. In the unmagnetized state they are arranged randomly and hence do not have magnetic behaviour.
If a magnet is heated, beaten, mishandled etc, it will lose its magnetism.
Why repulsion is the sure test for magnetism?
A magnet can attract the opposite pole of other magnet as well as the magnetic substance (iron cobalt nickel). SO, if A magnet attracts another object, we cannot say that the other object is a magnet. But if the magnet repels the object, then we can surely say that the other object is a magnet. Because “Like poles of a magnet repel each other”