LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034
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B.Sc. DEGREE EXAMINATION – PHYSICS
FIRST SEMESTER – April 2009
PH 1500 – PROP.OF MAT.& THERMAL PHYSICS
Date & Time: 20/04/2009 / 1:00 – 4:00 Dept. No. Max. : 100 Marks
PART- A
Answer ALL the questions (10×2=20 marks)
- State Newton’s second law of motion and obtain the unit of force.
- A metal disc of mass 1 kg and radius 0.1m is suspended at its centre by a wire of length 70 cm and radius 0.6 mm. The period of torsional oscillation is found to be 2.6 seconds. Calculate rigidity modulus.
- Give the expression for the energy stored in a stretched wire.
- State Hooke’s law.
- Write a brief note on lubricants.
- State Graham’s law of diffusion.
- Give two examples of Transport phenomena.
- What are intensive and extensive variables?
- Define the concept of entropy.
- Define latent heat of vaporization and write its unit.
PART- B
Answer any FOUR questions (4×7.5=30 marks)
- a) Explain gravitational field and gravitational potential. ( 4.5)
- b) Discuss the variation of acceleration due to gravity with altitude. (3)
- a) State Newton law of viscous flow. (3)
- b) Discuss Meyer’s modification of Poiseuille’s formula for the rate
of flow of gas through a capillary tube. (4.5)
- Describe Quincke’s drop method of finding the surface tension of Mercury.
14.a) Prove that change in entropy in a reversible process is zero. (5.5)
- b) Give any two conditions for reversibility of a process. (2)
- a) Derive Ehrenfest’s equation for second order phase transition. (5.5)
- b) Give two examples of second order phase transition. (2)
PART- C
Answer any FOUR questions (4×12.5=50 marks)
- a) Derive the relation between the various elastic constants of a material. (8.5)
- b) The modulus of rigidity and poisson’s ratio of the material of a wire are 2.87
x1010 N/m2 and 0.379 respectively. Find the value of young’s modulus of
the material of the wire. (4)
- a) Explain the molecular theory of surface tension. (4)
- b) Derive an expression for the excess of pressure over a curved liquid
surface. (8.5)
- a) State any four postulates of the kinetic theory of gases. (4)
- b) Deduce an expression for the pressure of a gas on the basis of this (8.5)
- Deduce the Maxwell’s thermo dynamical relations.
- a) Explain Joule-Kelvin experiment. (6)
- b) Obtain an expression for the Joule-Kelvin co-efficient. (6.5)
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