You have two identical needles. One of them is magnetized and the other is not. How, without the use of anything besides the two needles, could you tell which is magnetized?
By suspending the needles on in the air, the needle which orients itself in the north-south direction is magnetized
Explanation:
The only method to check a magnet individually without the help of another magnet or magnetic substance on the earth is by suspending it in the air which orients itself in the direction of the magnetic field of the earth.
This is when the non-magnetic needle will not align itself as the magnetic needle does in the magnetic field of the earth.
