Question

Magnetic permeability is maximum for the
A. Ferromagnetic substances
B. Diamagnetic substances
C. Paramagnetic substances
D. All of these

Answer 1

Hint: Magnetic permeability is the ability of a material to acquire magnetism when it is exposed to a magnetic field.

Complete step-by-step solution -
Magnetic permeability is the ratio of magnetic induction to magnetic intensity, it helps us to measure a material's resistance to the magnetic field or we can say that the measurement of the degree up to which magnetic field can penetrate through a material.
Actually when we place a material within a magnetic field the magnetic forces of the material's electrons are affected and this effect is known as Faraday's Law of Magnetic Induction but materials react differently in the presence of an external magnetic field and this reaction is actually depends on the number of factors like the atomic and molecular structure of the material and the net magnetic field associated with the atoms.
Magnetic permeability is maximum for the ferromagnetic materials because they have a large positive susceptibility to the external magnetic field; they show a very strong attraction to magnetic fields and also when the external field is removed they can retain their magnetic properties.
The reason is that ferromagnetic materials have some unpaired electrons so their atoms have a net magnetic moment, the presence of magnetic domains in them is the reason they have very strong magnetic properties, in these domains a large numbers of atom's moments (1012 to 1015) are aligned parallel therefore the magnetic force within the domain is strong.
Hence the correct option is A.

Note: When a ferromagnetic material is in unmagnetized state the net magnetic field for the part as a whole is zero because the domains are randomly organized and when a magnetizing force is applied these domains become aligned in order to produce a strong magnetic field within the part, some examples of ferromagnetic materials are iron, nickel and cobalt etc.