Test: Magnetism and Matter - 2 - CUET Humanities MCQ

Susceptibility  of a paramagnets is small and positive, and that of a diamagnets is small and negative.
Now, relative permeability:

Hence, μ_r is slightly greater than unity for a paramagnets and slightly less than unity for a diamagnets. So, A is paramagnetic and B is diamagnetic.

To shield a sensitive magnetic instrument from outside fields, it should be placed inside a box of soft iron of high permeability because soft iron box with high permeability will not allow magnetic lines to enter inside the box.

Diamagnetism is very weak form of magnetism. It is not permanent because this magnetism exists only when the external field is applied.

Work done, W = MB(1-cosθ)
= 20 x 0.3(1 - cos30º)

Both assertion and reason are true and reason is the correct explanation of assertion.
A superconductor is a material that offers no electrical resistance and expels magnetic fields (Meissner effect) . All known superconductor materials exhibit superconducting properties when cooled to very low temperatures.

The materials suitable for making electromagnets should have high retentivity and low coercivity. Coercivity is usually measured in oersted or ampere/meter units. When the coercive field of a ferromagnet is large, the material is said to be a hard or permanent magnet.

According to Curie's law for paramagnetic materials, susceptibility is inversely proportional to temperature.
X ∝ (1/T)

Bismuth is the strongest diamagnetic substance.