LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034
B.Sc. DEGREE EXAMINATION – PHYSICS
THIRD SEMESTER – SUPPLEMENTARY – JUNE 2012
PH 3505/PH 3503 - THERMODYNAMICS
Date : 28-06-2012
Time : 2:00 - 5:00
Dept. No.
Max. : 100 Marks
SECTION – A
Answer ALL the questions.
10×2 = 20 Marks
1. State the law of equipartition of energy.
2. What is Brownian motion?
3. Calculate the molar heat capacities of a gas if the ratio of the heat capacities is 1.30.
Given R = 8.31J/mol-K.
4. What is meant by superfluidity?
5. Define intensive and extensive variables. Give examples.
6. What is the physical significance of entropy?
7. Define Helmholtz and Gibbs functions.
8. What are the characteristics of a second order phase transition? Give an example.
9. Define phase space. What is the volume of unit cell in phase space?
10. Define solar constant.
SECTION - B
Answer any FOUR questions.
4 × 7.5 = 30 Marks
11. (a) Define mean free path.
(2)
(b) Derive an expression for the mean free path of molecules in a gas and discuss the correction applied
by Boltzmann and Maxwell.
12. Describe Linde’s experimental method of liquefying air.
(5.5)
(7.5)
13. (a) State first law of thermodynamics.
(2)
(b) Applying the first law thermodynamics derive an equation for the adiabatic process of a gas.(5.5)
14. (a) Define Joule-Kelvin coefficient and derive an expression for it.
(b) Discuss the significance of Joule-Kelvin coefficient.
15. (a) Obtain the relation connecting entropy and probability.
(2+4)
(1.5)
(5)
(b) An electron gas obeys the Maxwell-Boltzmanm statistics. Calculate the average thermal energy of an
electron in the system at 400K. Given Boltzmann constant = 1.38×10-23 JK-1.
(2.5)
SECTION - C
Answer any FOUR questions.
4 × 12.5 = 50 Marks
16. (a) What are transport phenomena?
(2.5)
(b) Derive an expression for the thermal conductivity of a gas using the kinetic theory of gases.
(10)
17. (a) Explain, with theory, Clement and Desormes method of determining the ratio of specific heat
capacities of a gas.
(10)
(b) Discuss the important properties of liquid HeliumII.
(2.5)
18. (a) Derive Clausius – Clapeyron latent heat equation.
(6)
(b) Write a note on Clausius inequality.
(4.5)
(c) Calculate the change in entropy when 0.0273kg of ice at 0ºC is converted into water at the same
temperature. Given L = 336×103J/kg.
(2)
19. Derive Maxwell’s thermodynamic relations.
(12.5)
20. (a) Using Bose-Einstein statistics derive Planck’s radiation law for black body radiation.
(b) Deduce Wein’s displacement law and Rayleigh-Jeans law.
$$$$$$$
(9.5)
(3)