Question

___is the surest test for magnetism.

Answer 1

Attraction can occur in the case of two magnets (with opposite poles brought together) as well as between a magnet and ferrous objects such as iron. Therefore, if both the pieces attract each other, they may be magnets or one may be the magnet and other may be a ferrous material. Whereas, repulsion is possible only in case of two magnets (with same poles brought together). Therefore repulsion is a true test for magnetism.