Question

If a diamagnetic substance is brought near the north or south pole of a bar magnet, it is:
(A) Attracted by both poles
(B) Repelled by both poles
(C) Repelled by the north pole and attracted by the south pole
(D) Repelled by the south pole and attracted by the north pole

Answer 1

Hint
Diamagnetic substances have unaligned magnetic domains. In the presence of magnetic fields, they align themselves such that they repel the magnetic field. As soon as the external magnetic field is removed, the diamagnetic substances lose their magnetic nature.

Complete step by step answer
Diamagnetic substances are those which create a magnetic field in the direction opposite to the externally applied magnetic field. They lose this magnetism when the external magnetic field is removed. Also, diamagnetic substances do not have unpaired electrons and magnetic lines of force do not pass through them. Now because they create an induced magnetic field and unavailability of free electrons in them, they are repelled by the magnetic fields. Therefore, the correct answer is option (B). Some e.g. of diamagnetic substances are gold, copper, mercury.

Note
The susceptibility of a diamagnetic substance is negative. This means that they will always repel the external magnetic field. Knowing such facts helps to answer the question quickly.
Susceptibility of a material is the measure of how much the material will magnetize in the presence of an externally applied magnetic field. Diamagnetic substances produce fields in the direction opposite to the applied field and so their susceptibility is negative.