Question

Harish was asked to identify a piece of soft iron put in a basket of 10 magnets of the same shape and size. Which is the easiest way to identify the iron piece at the earliest?

• A. By passing a current through the magnet.
• B. By conducting repulsion test using any two magnets at a time.
• C. By bringing another strong magnet near the basket.
• D. By dropping all magnets into the water.

Answer 1

The correct option is B By conducting repulsion test using any two magnets at a time.

Repulsion is a sure test of magnetism. Harish can conduct the repulsion test by taking two magnets at a time. If at all they repel, then both must be magnets. If they only attract then one of them must be the iron bar. To identify the iron bar among these two we can repeat the test for each of them with any other magnet in the basket.