Three identical iron bars are kept on a table. Two out of three bars are magnets. In one of the magnets the North–South poles are marked. How will you find out which of the other two bars is a magnet? Identify the poles of this magnet.

• Suspend the bar magnet with marked poles freely using a stand and thread.
• Slowly bring another magnet near the south pole of the suspended magnet.
• If the magnet attracts towards it, that will be the north pole of another magnet and vice versa.

• Repeat the above steps with the third magnet.

Unlike poles attract and like poles repel each other.