LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

**B.Sc.** DEGREE EXAMINATION – **PHYSICS**

THIRD SEMESTER – **APRIL 2012**

# PH 3505/PH 3503 – THERMODYNAMICS

Date : 26-04-2012 Dept. No. Max. : 100 Marks

Time : 9:00 – 12:00

__PART – A__

**Answer ALL the questions: (10×2=20)**

- Define Brownian Motion.
- Give the unit of thermal conductivity.
- Write down the equations of state for an ideal gas when it undergoes a

reversible isothermal and adiabatic changes.

- Define super fluidity.
- Given of an ideal gas is 2R, where R is the gas constant, determine the adiabatic

exponent .

- State the 2
^{nd}law of thermodynamics. - Write down the Gibbs – Helmholtz equation.
- Define phase transition. Give an example.
- Define microstates and macrostates.
- Classify the following particles according to the statistics they obey:
- i) electrons ii) photons iii) protons and iv) helium-4.

__PART – B__

**Answer Any FOUR questions: (4×7.5=30)**

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- Obtain an expression for the coefficient of thermal conductivity of a gas, on the basis of

kinetic theory of gases.

- Describe Linde’s process for the liquefaction of air.
- a) Write the first law of thermodynamics. What does it signify? (2+5.5)
- b) One mole of oxygen, initially at 17°C, is adiabatically compressed so that its pressure

becomes 10 times the initial value. Find its final temperature and the work done.

- Obtain the Maxwell’s thermodynamic relations.
- a) Define thermodynamic probability. (2+5.5)
- b) Obtain an expression for the solar constant in terms of the Sun’s

temperature, its radius, the mean Sun-Earth distance etc.

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__PART – C__

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**Answer Any FOUR questions:** **(4×12.5=50)**

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- Discuss Langevin’s theory of Brownian motion.
- a) Discuss Clement-Desormes method to determine the ratio of specific heats.
- b) Describe the properties of He I and He II. (8+4.5)
- a) Define reversible and irreversible processes.
- b) Obtain the Clausius inequality. (4+8.5)
- Explain Joule-Kelvin effect. Obtain an expression for the Joule-Kelvin coefficient.

Discuss the significance of the various terms in it.

- Obtain the Maxwell-Boltzmann distribution for an ideal gas.

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