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Magnetism

Magnetic poles

You know iron is a magnetic material. An iron bar can easily be converted into a bar magnet. Do you know what makes iron so special that it can be converted into a magnet?

Moreover, when you break a bar magnet made up of iron into pieces, every piece acts as an individual magnet. However small be the pieces, they all have magnetic properties. How does this happen?

The answer is already given. If you manage to break a magnet up to its molecular level, you will find that every iron molecule acts like an individual magnet. Therefore, we can say that each iron molecule is a magnet.

Then, why don’t all iron objects act like a magnet?

In answer to this question, let us perform a small experiment.

Take three bar magnets. Arrange them to form a triangle, such that the north pole of one magnet faces the south pole of another magnet. Now, the combined structure does not have any specific polarity. When you bring the north pole of another magnet close to this structure, you cannot say with surety as to whether the structure would attract or repel the magnet.

The same thing happens in a magnetic material. In normal conditions, all molecules are randomly organised within the material in such a manner that the magnetic effect of one molecule gets cancelled out by the magnetic effect of the other molecules. You can see a few such arrangements of molecules and how they are arranged in a material in the given pictures.

Closed molecular arrangements

Molecular arrangement in a magnetic material

Now, when a pole—say the north pole—of a magnet is brought close to the magnetic material, the south poles of all the molecules get attracted towards the north pole of the magnet. Therefore, all the molecules are arranged in the manner as shown in the following figure.

Molecular arrangement …

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