Download BBA IInd SEMESTER EXAMINATION 2008-09

B.Sc. (Hons.) Physics III (Third) Semester Examination
2012-13
Course Code: BAS305
Paper ID: 0983205
Thermal and Low Temperature Physics
Time: 3 Hours
Max. Marks: 70
Note: Attempt six questions in all. Q. No. 1 is compulsory.
1.
a)
b)
c)
d)
e)
f)
g)
h)
2. a)
b)
3.
Answer any five of the following (limit your answer to 50
words).
(4x5=20)
Define thermodynamics and state different approaches of
study of thermodynamics.
Explain mean free path in Kinetic theory of gases.
What are the reversible and irreversible processes in
thermodynamics?
Explain second law of thermodynamics.
Write short note on black body spectrum.
What is Wien’s displacement Law?
Define superconductivity with example.
Determine the heat to be supplied to a Carnot engine
operating between 400 °C and 15 °C.
What is law of equipartition of energy? Explain distribution
of molecular speed.
(5)
Prove the thermodynamic equation of Vander Waals gas with
its physical significance.
(5)
Describe the Carnot cycle and obtain expression for its
efficiency as applied to a heat engine. What would be the
maximum efficiency of engine that is working between the
temperature of 1150 °C and 27 °C?
(10)
4. a)
Define the entropy and also explain how it is measured in
irreversible process?
(5)
b) Explain why the slope of constant volume line is more than
the slope of constant pressure line on T-S diagram.
(5)
5. a) Explain the difference between isentropic process and
adiabatic process.
(5)
b) A heat engine operates between source at 600 K and sink at
300 K. Heat supplied by source is 500 kcal/s. Evaluate
feasibility of engine and nature of cycle for the following
conditions
(5)
i)
Heat rejected being 200 kcal/s.
ii)
Heat rejected being 400 kcal/s.
6.
Prove Maxwell’s thermodynamical equations and explain
their applications.
(10)
7.
What is ultraviolet catastrophe? Prove the Planck’s radiation
formula for blackbody radiation.
(10)
8.
Write notes on any two of the following:
a) What is third law of thermodynamics?
b) Explain Soft and hard superconductor.
c) Joul Thomson effect.
(2x5=10)