Question

What are diamagnetic substances? Give one example.

Answer 1

Hint: Other than the current carrying wire and a magnet, some materials also show magnetism. Meaning the materials are magnetised when placed in an external magnetic field. One these materials are diamagnetic materials.

Complete answer:
We know that a current carrying wire and magnet show magnetism. Other than these, there are other materials that show magnetism. This means that the material interacts with an external magnetic field that is produced in their surrounding.
On the basis of the interaction of these materials with the external magnetic field, the materials are categorised into paramagnetic materials, diamagnetic materials and ferromagnetic materials.
The diamagnetic materials are those materials which weakly repel the external magnetic field.
Let us discuss the reason for the behaviour of diamagnetic material. We know that elements are made of electrons and these electrons revolve in their orbits. Due to the rotation of each electron there is a magnetic moment produced inside the material. However, the electrons revolve in such a way that the net magnetic moment of the whole material is zero.
When the diamagnetic material is placed on an external magnetic field, the material is weakly magnetised in such a way that it repels the external field.
The examples of diamagnetic materials are copper, gold, antimony, silver, lead and hydrogen.

Note:
- Paramagnetic materials are those materials that are weakly attracted by the external magnetic field. Examples of paramagnetic materials are aluminium, sodium and calcium.
- Ferromagnetic materials are those materials that are strongly magnetised and attracted when they are placed in the external magnetic field. Examples of ferromagnetic materials are iron, cobalt and nickel.
- Note that once the external magnetic field is removed, the paramagnetic and diamagnetic materials demagnetise. Whereas the ferromagnetic materials remain magnetised.