LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034
B.Sc. DEGREE EXAMINATION – PHYSICS
SIXTH SEMESTER – APRIL 2011
PH 6610/PH6606 – SOLID STATE PHYSICS
Date : 07-04-2011 Dept. No. Max. : 100 Marks
Time : 9:00 – 12:00
PART – A
Answer all questions. All questions carry equal marks. (10×2=20marks)
- Define crystal lattice?
- What is coordination number?
- Write Laue equations.
- Why are X-rays used for diffraction studies in crystals?
- Give the classical value of specific heat at high temperatures and at T = OK.
- What is the basic difference between Einstein’s model and Debye model?
- Mention the differences between free electron gas and ordinary gas?
- What is Hall effect?
- What is Meissner effect?
- Explain Type I superconductor.
PART – B
Answer any FOUR questions. (4×7.5=30marks)
- a) What are Miller indices?
- b) Calculate the ratio of d100 : d110 : d111 for simple cubic structure.
- Write a note on neutron diffraction.
- Debye temperature of diamond is 1850 K. Calculate the molar specific heat for diamond at 20 K. Also compute the highest lattice frequency involved in the Debye theory.
(R = 8.4 J.mol– 1.K– 1 ,h = 6.62 X 10– 34 Js kb = 1.38 X 10– 23 J.K– 1 ).
- Discuss the variation of density of states with energy for a free electron gas in 3-d.
- Explain Josephson effect.
PART – C
Answer any FOUR questions. (4×12.5=50marks)
- Describe three dimensional lattice types with suitable diagrams.
- Explain the powder method of X-ray diffraction studies.
- Derive an expression for the specific heat of a solid on the basis of Einstein’s theory.
- Derive an expression for the paramagnetic susceptibility of a free electron gas.
- Explain the occurrence of superconductivity based on BCS theory.
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