Question

how can we find polarity of unmarked steel bar with the help of bar magnet?

Answer 1

Explanation:

Another way of testing the polarity of an unmarked magnet is to use an already marked magnet to highlight the north and south poles. The marked magnet attracts itself to the opposite pole of the unmarked magnet. For example, the marked magnet's south pole will attach itself to the north pole of the unmarked magnet.