Question

Two bars of soft iron exactly alike are given. One of them is a magnet. Without using anything more, how would you find which is a magnet -

• A. By bringing two bars near and noting which one is attractive. The attracting one is a magnet
• B. By bringing two bars near and noting which one is repelling. One which repels is an ordinary iron.
• C. By rubbing one bar with the other and noting which becomes a magnet. The bar which is magnetized is an ordinary iron.
• D. One bar is placed flat horizontally on the table and the other bar is held vertical with its one end on the middle of the first bar. If there is the attraction between the two, the vertical bar is magnet otherwise ordinary iron.

Answer 1

The correct option is D One bar is placed flat horizontally on the table and the other bar is held vertical with its one end on the middle of the first bar. If there is the attraction between the two, the vertical bar is magnet otherwise ordinary iron.

If there is the attraction between the two, the vertical bar is magnet otherwise ordinary iron. This is the only way to recognize them since every magnet has a null point exactly in the middle of its geometric length. That point has no attractive or repulsive power.