Question

Imagine you are given 2 nails. Your task is to develop a step by step procedure for determining by experiment if one is magnetized or if both are. If only one is, how can you find out -using just the two nails- which is magnetized? Hint: the middle of the nail is magnetically neutral even if the nail is magnetized.

Answer 1

Nails can be made magnetic by rubbing them with magnets.

Now we have two nails which we don't know whether magnetic are not. we need to check,

First step is, as we know magnetic monopoles don't exist there is always magnetic dipole of opposite poles viz north and south pole exist.

Now take two nails if there is no interaction in between them certainly both of them is neutral.

Now we don't know whether one or both are magnetic.

Take them, if one nail of them attracts both side of the other nail then we can be sure only one nail is magnetic.

But if there is repulsion from one side that means both of them are magnetic.

Now the question remains if one of them is magnetic, how to tell which one is magnetic.

Now move one end of either nail along other if force remains same through out then nail in your hand is magnetic but if force decreases and then again increases then nail placed on table is magnetic.