M.Sc. DEGREE EXAMINATION, NOVEMBER 2017
First Semester
Physics
SOLID STATE PHYSICS
(CBCS 2014 onwards)
Time 3 Hours Maximum 75 Marks
Part A (10 x 2 20)
Answer all questions.
1. Find the packing fraction of SC structre.
2. What is creep? What is its mechanism?
3. What is measured by the periodicity in de Haas-Van
Alphen effect?
4. For U-process to occur, what should be the minimum
energy of the phonons?
5. What is polarization catastrophe?
Sub. Code
4MPH1C4
AFF-4860
2
Sp4
7. State Hund's rule.
8. How the susceptibility of an antiferromagnet varies with
temperature?
9. What are SQUIDS?
Part B x 5 25)
Answer all questions.
11. Define fundamental types of lattices in two and
three dimensions.
Or
Derive the expression for the atomic structure
factor. What role does it play in X-ray diffraction
studies.
12. If the elastic stissness coefficient C11 for Nacl is
5 dynes/cm2, find the force constant and
calculate the restrahlen frequency for this crystal.
Or
How can a neutron be inelastically scattered by an
optical phonon of zero wave vector?
13. Derive an expression for electrical conductivity of a
metal.
Or
Describe tight binding approximation for
calculating the energy states of an electron in a
solid.
14. Write short note on "Ferroelectric domains".
Or
Discuss briefly about cooling by adiabatic
demagnetization.
AFF-4860
3
Sp4
15. Give an account of Weiss theory of ferromagnetism.
On the basis of this theory, how will you explain
hysteresis and curie point.
Or
Write short note on "High temperature super
conducting materials and its applications".
Part C 10 30)
Answer any three questions.
16. Explain the concept of reciprocal lattice. Discuss its
properties. Calculate the reciprocal lattice for a direct fcc
lattice.
17. Find dispersion relation for a one-dimensional crystal
with two types of atoms and discuss the nature of the
optical and acoustic moles.
18. Discuss the Kronig-Penny model for a linear lattice. How
does it lead to formation of energy bands in solids?
19. Obtain an expression for paramagnetic susceptibility of
free electrons on the basis of classical laws. Discuss its
inadequacy and show how panli modified it.
20. Give an elementary treatment of BCS theory of super
conductivity. How does it explain the energy gap at OK
and the isotope effect?
————————