Correct option is D
Permeability (μ) is a measure of how easily a material can support the formation of a magnetic field within itself.
Ferromagnetic materials, such as iron, nickel, and cobalt, have very high permeability because they can easily become magnetized and can support strong magnetic fields.
This high permeability is due to the alignment of magnetic domains within the material, which enhances its ability to conduct magnetic flux.
Magnetic permeability is a property that basically allows magnetic lines of force to pass through a material.
In other words, the magnetic permeability of a material can also be said to be its magnetization capability.
This helps in determining how much magnetic flux can the material support, which will pass through it.
Magnetic permeability is defined as the ratio of the magnetic induction to the magnetic intensity.
It is a scalar quantity and is denoted by the symbol μ.
Magnetic permeability helps us measure a material's resistance to the magnetic field or measure the degree to which a magnetic field can penetrate through a material.
If the material has greater magnetic permeability, the greater will be the conductivity for magnetic lines of force.
Permeability also depends on several factors, such as the nature of the material, humidity, position in the medium, temperature, and frequency of the applied force.
Magnetic permeability is always positive and can vary with a magnetic field. On the other hand, the opposite of magnetic permeability is magnetic reluctivity.
The magnetic permeability formula is given as follows;
Magnetic permeability (μ)=B/H
Where B= magnetic intensity and H= magnetising field.
Ferromagnetic materials do not have constant relative permeability.
Pure iron and many alloys have relative permeability greater than 100000; as the magnetizing field increases, the relative permeability increases.
Therefore, ferromagnetic materials have the strongest magnetic properties. Iron is an example of ferromagnetic material.
Explanation of the Options:
(a) very low
This is incorrect. Materials with very low permeability are typically non-magnetic materials, not ferromagnetic.
(b) low
This is incorrect. Low permeability is characteristic of materials that do not support magnetic fields well, unlike ferromagnetic materials.
(c) high
This is partially correct, but "very high" is more accurate.
(d) very high
This is correct. Ferromagnetic materials have very high permeability, making them highly effective at conducting magnetic flux.
Therefore, the correct answer is (d) very high.
