DISTANCE EDUCATION
M.Sc. (Physics) DEGREE EXAMINATION, MAY 2018.
SOLID STATE PHYSICS
(2008 onwards)
Time Three hours Maximum 100 marks
Answer any FIVE questions.
Each question carries 20 marks.
x 20 100)
1. Why are there no crystals with 5 and 7-fold
symmetry?
Describe the structure of cesium chloride.
Explain the significance of Brillouin zone with
reference to BCC and FCC lattice.
2. Write notes on diffraction of waves by crystals.
Obtain the Van der Walls — London equation and
hence show that the interaction energy is inversely
proportional to the 8th power of the distance
between the dipoles.
Explain covalent crystal with examples.
3. Obtain the dispersion relation for vibrations of
crystals with monatomic basis.
Write notes on thermal properties of phonons.
What are the consequences of theory of lattice
vibrations?
Sub. Code
23
DE-4064
2
WK 16
4. Derive expression for the number of orbitals per
unit energy range of free electron gas in three
dimensions.
Describe the nearly free electron model, origin and
magnitude of energy gap.
6. Explain donor states and acceptor states of semiconductor
crystals.
Obtain the expression for intrinsic carrier
concentration of semiconductor.
7. What is the relationship between dielectric constant
and polarizability?
Explain the quantum theory of paramagnetism.
Write a note on ferromagnetic order.
8. Explain anti-ferromagnetism and describe the
variation of its susceptibility with temperature.
Write a note on neutron magnetic scattering.
Explain magnetic bubble domains.