Name: Hysteresis: Property of Ferromagnetic Substances
Uploaded: 2019-07-19
Duration: 5 min 6 s
Description: The behaviour of ferromagnets is fascinating. The magnetic field due to a ferromagnet exhibits an interesting phenomenon known as hysteresis. Let’s explore.

Question

Distinguish the magnetic properties of a dia, para and ferromagnetic substances in terms of
(i) susceptibility,
(ii) magnetic permeability and
(iii) coercivity.
Give one example of each of these materials.
Draw the field lines due to an external magnetic field near a (i) diamagnetic, (ii) paramagnetic substance.

Accepted Answer

Properties Diamagnetic Paramagnetic Ferromagnetic

Susceptibility Susceptibility is small and negative. $- 1 < x_{m} < 0$ Susceptibility is small and positive. $0 \leq x_{m} < ε$ Susceptibility is very large. $x_{m} > 1000$

Magnetic permeability The magnetic permittivity is less than the permittivity of free space. $μ < μ_{0}$ The magnetic permittivity is greater than the permittivity of free space. $μ > μ_{0}$ The magnetic permittivity is much greater than the permittivity of free space. $μ ≫ μ_{0}$

Coercivity The coercivity for diamagnetic substance is zero. The coercivity for paramagnetic substance is zero. The coercivity for ferromagnetic substance is positive.

Example of these materials are
(i) Paramagnetic: Oxygen $(O_{2})$
(ii) Diamagnetic: Nitrogen $(N_{2})$
(iii) Ferromagnetic: Iron $(F e)$

(i) The field lines due to an external magnetic field near a diamagnetic substance.

(ii) The field lines due to an external magnetic field near a paramagnetic substance.

Important Questions on Magnetism

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