Question

Using a compass needle how would you distinguish between three bars similar in shape and appearance if one is brass, the second is an unmagnetized iron and the third is a permanent magnet?

Answer 1

1. A compass needle is a small magnet.
2. Brass is an alloy of copper and zinc and does not have any magnetic properties.
3. Unmagnetized piece of iron is ferromagnetic substance and are attracted by magnets.
4. A permanent magnet attracts or repels another magnet.
5. When a compass needle is bought near one of the bars and it doesn't show any deflection then a bar is brass.
6. When a compass needle is bought near one of the other bars and it is attracted by the compass then a bar is an unmagnetized iron.
7. When a compass needle is bought near one end of the bar and it shows attraction and for another end, it shows repulsion then a bar is a permanent magnet.