LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034
B.Sc. DEGREE EXAMINATION – PHYSICS
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FIRST SEMESTER – NOV 2006
PH 1500 – PROP.OF MAT.& THERMAL PHYSICS
(Also equivalent to PHY 500)
Date & Time : 01-11-2006/1.00-4.00 Dept. No. Max. : 100 Marks
PART-A
Answer ALL the questions (10×2=20 marks)
- Two spheres of masses 10 kg and 20 kg are 500 cm apart. Calculate the force of attraction between the masses.
- What is geometrical moment of inertia in bending of beams?
- Give the SI unit and dimensions of coefficient of viscosity.
- What is critical velocity of a liquid?
- Water wets glass surface, while mercury does not. Why?
- Calculate the mean free path of a gas molecule of diameter 3.2 Å. The number of molecules per unit volume is 21.5x 1023 m-3.
- What is an intensive variable? Give two examples.
- Give the Classius statement of the second law of thermodynamics.
- State the law of equipartition of energy.
- What is perpetual motion machine of the second kind?
PART-B
Answer any FOUR questions (4×7.5=30 marks )
- Derive an expression for the variation of acceleration due to gravity with latitude.
- a) Derive an expression for the bending moment of a bar. (4)
- b) Find the energy stored in a wire 5 metre long and 10-3 metre in diameter when it is stretched through 3×10-3 metre by a load. Young’s modulus of the material is 2×1011 N/m2 . (3.5)
- a) Obtain Mayer’s formula for the flow of a gas through a capillary tube. (5.5)
- b) State any two properties of a good lubricant. (2)
- a) Derive Classius- Clapeyron equation for liquid-vapour equilibrium. (5)
- b) One kilogram of water at 373K is mixed with 1 kilogram of water at 273K. Estimate the change in entropy. (2.5)
- Derive Maxwell’s thermodynamical relations.
PART-C
Answer any FOUR questions (4×12.5=50 marks)
- a) Derive the relationship between the three elastic moduli and deduce an expression for Poisson’s ratio. (7.5)
- b) Calculate the Poisson’s ratio for the material whose
Young’s modulus = 12.25X1010 N/m2 and
Rigidity modulus = 4.55 X 1010 N/m2. (5)
- a) Describe with relevant theory the Quincke’s method for the determination of surface tension and angle of contact of mercury. (10)
- b) What would be the pressure inside a small air bubble of 10-4 m radius, situated just below the surface of water? Surface tension of water is 70×10-3 N/m and the atmospheric pressure = 1.012×105 N/m2. (2.5)
- a) Explain the transport Phenomena. Derive an expression for the coefficient of viscosity of a gas on the basis of the kinetic theory of gases. (10)
- b) How does the coefficient of viscosity of gas depend upon temperature and pressure ? (2.5)
- a) Obtain the Classius inequality relation of thermodynamics (7.5)
- b) Derive Ehrenfest’s equation for a second order phase transition. (5)
- Explain Joule-Kelvin experiment and inversions curve and obtain an expression for Joule-Kelvin co-efficient.