How do characteristic X-ray lines originate? Using Bohr's atomic model deduces a relation between the frequencies of the K series X-ray lines and atomic numbers of the emitting elements. Do you expect this relation to be exact?

Discuss how stars are classified on the basis of their spectra. Briefly mention what different informations about stars can be obtained from the study of their spectra.

What are anti-Stokes lines? Do they occur in both Raman and Compton scatterings? Explain how they arise and how temperature affects their intensities.

What are the transitions leading to the emission of the D lines of Sodium? Deduce the expression for the Lande splitting factor. g and calculate its values for the states involved in the emission of D lines. Hence find the change of energies of these levels when a sodium source is placed in a magnetic field which is not too high.

Write an explanatory outline of thermal ionization of atoms and the spectra of stars, specifying what information we get from the latter.

What is meant by L-S coupling? Deduce the spectral terms which can arise from 3p4p electron configuration. Would all these terms exist in 3\mathrm{p}^2 configuration? Write expressions for the square of angular momentum for L=2 and also for the component of angular momentum for \mathrm{m}_j=2 as given by quantum mechanics.

What did the Stern-Gerlach experiment establish? Explain your answer. Would the experiment succeed if it were performed with a beam of free electrons?

State and explain Pauli's exclusion principle. Estimate the total number of electron states in a many electron atom for a given principal quantum number n.

Discuss the origin of line spectrum and continuous spectrum of X-rays. What is Duance and Hunt limit for X-ray spectrum? Can you obtain the value of 'h' (Planck's const.) precisely from a knowledge of the Duane and Hunt limit. An X-ray tube is operated it 20\text{ kV}. Determine the wavelength limit of continuous X-rays.

In observing the Raman spectrum of a sample, using 2537\text{ \AA} as the exciting line, one gets a Stokes line at 2683\text{ \AA}. Deduce the Raman shift in \text{cm}^{-1} units. What information does it give? Compute the wavelength, in \text{\AA} units, for the corresponding Stokes and anti-Stokes tines if the exciting line is 5461\text{ \AA}.

The series limit due Balmer series for hydrogen is given by 3.65 \times 10^{-5}\text{ cm.} and an element is found to give k-series wavelength down to 10 \times 10^{-10}\text{ cm,} Find the atomic number of the element.

Write a brief note (about 200\text{ words}) on X-ray absorption edges.

Give an account of Pauli's exclusion principle. Show how it leads to the building up of the Periodic Table of elements. The description must particularly emphasize shell structure and the placing of alkali metals, halogens and inert gases in the Periodic Table.