Would the maximum possible magnetisation of a paramagnetic sample be of the same order of magnitude as the magnetisation of a ferromagnet ?

Why does a paramagnetic sample display greater magnetisation (for the same magnetising field) when cooled?

Explain qualitatively on the basis of domain picture the irreversibility in the magnetisation curve of a ferromagnet.

A domain in ferromagnetic iron is in the form of a cube of side length 1 mu m . Estimate the number of iron atoms in the domain and the maximum possible dipole moment and magnetisation of the domain. The molecular mass of iron 55g/mole and is density is 7.9 g//cm^(3) . Assume that each iron atom has a dipole moment of 9.27 xx 10^(-24) A m^(2) .

It is tempting to think that all possible transitions are permissible, and that an atomic spectrum arises from the transition of the electron from any initial orbital to any other orbital. However, this is not so, because a photon has an intrinsic spin angular momentum of sqrt2 (h)/(2pi) corresponding to S = 1 although it has no charge and no rest mass. On the other hand, an electron has got two types of angular momentum : Orbital angular momentum, L=sqrt(l(l+1))h/(2pi) and spin angular momentum, arising from orbital motion and spin motion of electron respectively. The change in angular momentum of the electron during any electronic transition must compensate for the angular momentum carries away by the photon. to satisfy this condition the difference between the azimuthal quantum numbers of the orbital within which transition takes place must differ by one. Thus, an electron in a d-orbital (1 = 2) cannot make a transition into an s = orbital (I = 0) because the photon cannot carry away enough angular momentum. An electron as is well known, possess four quantum numbers n, I, m and s. Out of these four I determines the magnitude of orbital angular momentum (mentioned above) while (2n m determines its z-components as m((h)/(2pi)) he permissible values of only integers right from -1 to + l. While those for I are also integers starting from 0 to (n − 1). The values of I denotes the sub shell. For I = 0, 1, 2, 3, 4,..... the sub-shells are denoted by the symbols s, p, d, f, g, .... respectively The maximum orbital angular momentum of an electron with n= 5 is

A Rowland ring of mean radius 15 cm has 3500 turns of wire wound on a ferromagnetic core of relative permeability 800. What is the magnetic field B in the core for a magnetising current of 1.2 A ?

Of the following four wires of same material which will have maximum increase in length and which will have minimum increase in length if all are under the action of same force? Arrange the wires in the descending order of increase in length i) Natural length = 0.5m, diameter = 0.5mm ii) Natural length = 1m, diameter = 1mm iii) Natural length = 1.5m, diameter = 1.5mm iv) Natural length = 2.0m, diameter = 2mm