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

Explain photoelectric effect on the basis of Einstein theory.

Explain an activity to find the normal to a curved surface.

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

Explain the shape of XeF_(4) on the basis of VSEPR theory.

The given picture explains

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 ?

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) .