Chapter 20, Problem 25Q

To determine

Explain why the other end will attract a paper clip, if one end of the nail is in contact with a magnet.

Answer to Problem 25Q

Solution:

The magnet induces the alignment of electron spin moments with the magnet axis, thereby effectively turning the nail into a magnet.

Explanation of Solution

Introduction:

An object behaves like a magnet when it has large number of electrons having parallel spins.

If the magnet is strong, it will cause orientation of spins of electrons in single direction in other unmagnetized (magnetic)objects making it act like a magnet. Such magnets which are formed are also called temporary magnets because as soon as the effect of a strong magnet is removed, it becomes unmagnetized again.

If one end of the nail is in contact with the magnet, then the domains in the nail start aligning such that the end is in the contact with the magnet acquires an opposite pole of the magnet, that is, south pole and the other end of the nail will become a north pole.

Again a same process repeats when a paper clip is brought nearer to the slightly magnetized nail.

The domain with the north pole in the nail will make the domain in the paper clip to align in such a way that the end that is in the contact with the nail becomes south pole and the other becomes the north pole.

Since, the nail is a weaker magnet the domain of the paper clips is still weaker and there will be very little attraction between the paper clip and the nail.

Thus, nail attracts the paper clip to one end when its other end is in contact with magnet