Question

8. You have two iron rods which are identical in appearance, but one is a permanent magnet and the other is unmagnetized. What series of simple experiments can you perform, using only the two rods, which will allow you to determine which of the rods is the permanent magnet

Answer 1

Explanation: Let assume that bars are labeled A and B

Method 1

Using just the identical appearing bar magnet and unmagnetized iron bar.

Place the end of bar A in the middle of bar B.

If bar A sticks to bar B, then bar A is the magnet and bar B the umagnetized iron bar.

If bar A jumps to one of the ends of bar B, then bar B is the magnet.

Reason been that the magnetic field on a bar magnet is greatest at the two poles where the field comes out of the magnet. The center, between the poles, will be the weakest part of the field.

Method 2

Another solution would be to separate the two by quite some distance, float them on a piece of cork/wood in a plastic bucket or suspend them from long strings, then see which one consistently (eventually) lines up tending towards the Earth’s magnetic field.