Question

What are diamagnetic substances? Give one example.

Answer 1

For this question, we need to define what diamagnetic substances are. Also, we need to give one or more examples of such substances. Mention how diamagnetic substances behave in magnetic fields and whether their susceptibility is positive, negative or zero.

Complete answer:
Let us first define what magnetic substances are, magnetic substances are ones which can be magnetized and are strongly attracted to a magnet. These include elements such as iron, cobalt, nickel, etc.

Diamagnetic substances are those which are easily magnetized in the opposite direction when placed in a magnetic field. They are usually repelled by a magnetic field. In diamagnetic materials, the net dipole is zero due to pairing between the electrons. In an external magnetic field, the dipoles are induced in the diamagnetic materials in such a way that induced dipoles oppose the external magnetic field according to Lenz’s law. Therefore, all the materials whose atoms contain paired electrons show diamagnetic properties.

Some properties of diamagnetic substances:
-There is zero net atomic dipole as the resultant magnetic dipole is zero.
-In a magnetic field, diamagnetic substances repel.
-The magnetic susceptibility for diamagnetic substances is small and negative.
-They are independent of temperature and do not obey Curie’s law.
-When a diamagnetic liquid is placed in a watch glass placed on two pole pieces which are quite closer to each other than the liquid accumulates at the sides and shows depression in the middle where the field is strongest.

Examples of diamagnetic substances: Silver, Carbon, Zinc, Bismuth, Gold, Antimony, Marble, Water and many more.

Note: Unlike most magnetic substances, diamagnetic substances repel when placed in a magnetic field. The diamagnetism property is present in all materials and is independent of temperature. Diamagnetism is possible in all three states; solid, liquid and gas.