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Home » Answer the following questions:(a) Why does a paramagnetic sample display greater magnetisation (for the same magnetising field) when cooled?(b) Why is diamagnetism, in contrast, almost independent of temperature?(c) If a toroid uses bismuth for its core, will the field in the core be (slightly) greater or (slightly) less than when the core is empty?(d) Is the permeability of a ferromagnetic material independent of the magnetic field? If not, is it more for lower or higher fields?(e) Magnetic field lines are always nearly normal to the surface of a ferromagnet at every point. (This fact is analogous to the static electric field lines being normal to the surface of a conductor atevery point.) Why?(f) Would the maximum possible magnetisation of a paramagnetic sample be of the same order of magnitude as the magnetisationof a ferromagnet?
Answer the following questions:
(a) Why does a paramagnetic sample display greater magnetisation (for the same magnetising field) when cooled?
(b) Why is diamagnetism, in contrast, almost independent of temperature?
(c) If a toroid uses bismuth for its core, will the field in the core be (slightly) greater or (slightly) less than when the core is empty?
(d) Is the permeability of a ferromagnetic material independent of the magnetic field? If not, is it more for lower or higher fields?
(e) Magnetic field lines are always nearly normal to the surface of a ferromagnet at every point. (This fact is analogous to the static electric field lines being normal to the surface of a conductor at
every point.) Why?
(f) Would the maximum possible magnetisation of a paramagnetic sample be of the same order of magnitude as the magnetisation
of a ferromagnet?
CBSE | Class 12 | Magnetism and Matter | NCERT | Physics
Answer the following questions:
(a) Why does a paramagnetic sample display greater magnetisation (for the same magnetising field) when cooled?
(b) Why is diamagnetism, in contrast, almost independent of temperature?
(c) If a toroid uses bismuth for its core, will the field in the core be (slightly) greater or (slightly) less than when the core is empty?
(d) Is the permeability of a ferromagnetic material independent of the magnetic field? If not, is it more for lower or higher fields?
(e) Magnetic field lines are always nearly normal to the surface of a ferromagnet at every point. (This fact is analogous to the static electric field lines being normal to the surface of a conductor at
every point.) Why?
(f) Would the maximum possible magnetisation of a paramagnetic sample be of the same order of magnitude as the magnetisation
of a ferromagnet?

Answer –

(a) At a lower temperature, thermal motion is reduced, and the tendency to disturb the alignment of the dipoles is reduced.

(b) The induced dipole moment is always in the opposite direction as the magnetising field. As a result, the internal motion of the atoms caused by temperature has no effect on the material’s magnetic.

c) Bismuth is a diamagnetic material. As a result, a toroid with a bismith core will have a somewhat smaller field than one with an empty core.

(d) The magnetic field affects the ferromagnetic material’s permeability. Lower fields have more permeability.

(e) The boundary conditions of magnetic fields (B and H) at the interface of two media are used to prove this fundamental statement (which has a lot of practical applications). (When one of the media has a value of >> 1, the field lines almost always intersect this medium.)

(f) Of course. A paramagnetic sample with saturated magnetisation will have the same order of magnetisation, notwithstanding slight changes in the strength of the individual atomic dipoles of two distinct materials. Saturation, on the other hand, necessitates impractically high magnetising fields.

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