Question
You are given two identically looking bars A and B. One of these is a bar magnet and other an ordinary piece of iron. Give an experiment to identify which one of the two is a bar magnet. You are not to use any additional material for the experiment.
Solution
Bring both the bars closer to each other and, if in case there is repulsion in between the bars, then both bars are magnetised. If the bars get attracted to each other, then only 1 bar is magnetised.
To identify which bar is bar magnet:
Lay bar A on the table and hold bar B in your hand with it's one end placed in the middle of bar A. If the bars tend to get attracted then we can say that bar B (in hand) is magnetised and is the bar magnet.