N A L A N D A O P E N U N I V E R S I T Y
M.Sc. Physics, Part-II
PAPER-XV
(Advanced Condensed)
Annual Examination, 2017
Time 3 Hours. Full Marks 80
Answer any Five Questions. All questions carry equal marks.
1. What is Madlung constant Show that the madlung constant for an infinite linear chain of ions
of alternating unit charge at an equilibrium saparation is 2 2 .
2. Obtain dispersion relation for a one dimensional crystal with two types of items and discuss the nature of optical and acoustic modes.
3. Establish the Lyddane-Sachs-Teller relation between the static dielectric constant and that at optical frequencies.
4. What is a phonon Enumerate the salient features of phonon.
What are normal and umklapp processes Explain with the help of suitable vector diagrams.
5. Derive an expression for the thermal conductivity of a crystal. Discuss the variation of thermal conductivity with temperature.
6. Discuss the theory of indirect transition and obtain an expression for transition probability.
7. Give the theory of interaction of electron with acoustic phonons.
8. Present an account of Ginzberg-Landau theory. How do you obtain coherence length
9. Discuss A.C. Josphson effect. Show that the current oscillates with frequency
10. Discuss the theory of Isomer shift and electric quadrupole interaction vis-a-vis Mössbauer spectrum.