You are given a magnet which does not have the poles marked. How can you find its poles with the help of another magnet which has its poles marked?
To find the poles of an unmarked magnet using a marked magnet, bring the North pole of the marked magnet close to one end of the unmarked magnet.
If the ends attract each other, then that end of the unmarked magnet is its South pole.
If the ends repel each other, then that end of the unmarked magnet is its North pole. The other end will automatically be the opposite pole.
This method works because unlike poles (North-South) attract each other while like poles (North-North or South-South) repel each other.
Explanation
Activity 4.5 and Activity 4.6 demonstrate the principle of attraction and repulsion between magnetic poles. The chapter states: 'unlike poles of two magnets, that is, the North pole of one magnet and the South pole of another magnet, attract each other. The like poles, that is, either the North poles or the South poles of both magnets, repel each other.' By observing whether the marked magnet's North pole attracts or repels the unmarked magnet's end, we can identify the pole.
Solution Steps
Bring the North pole of the marked magnet close to one end of the unmarked magnet.
If the ends attract each other, that end of the unmarked magnet is its South pole.
If the ends repel each other, that end of the unmarked magnet is its North pole.
The other end will automatically be the opposite pole.
Unlike poles (North-South) attract each other while like poles (North-North or South-South) repel each other.