Annamalai University 2008-1st Year B.Sc Physics
B
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19. (a) Explain the radial flow of heat method
of determining the thermal conductivity of a material.
(OR)
(b) A bar of length 30 cm and uniform cross-section 5 cm consists of two halves AB of copper and BC of iron welded together at B. The end A is maintained at 200C and C at 0C. The sides of the bar are thermally insulated. Find the rate of flow of heat along the bar when the steady state is reached. Thermal conductivity of copper is 385 Wm"1 K"1 and that of iron is 51-3 Wm-1 K'1.
20. (a) State and prove Carnots theorem.
(OR)
(b) Obtain an expression for efficiency of Otto engine.
SECTION - C (3x15 = 45)
Register Number:
Name of the Candidate :
5 2 6 0 B.Sc. DEGREE EXAMINATION, 2008
(PHYSICS)
(FIRST YEAR)
(PART - III)
(PAPER - I)
530.PROPERTIES OF MATTER AND THERMAL PHYSICS
December ] [ Time : 3 Hours
Maximum : 100 Marks
Answer any TEN questions.
All questions carry equal marks.
1. What are the theoretical limits to the value of Poissons ratio ?
2. Define the term elastic fatigue.
3. Define modulus of elasticity and give its dimensions.
4. Define: angle of contact.
5. Define surface energy. How it is related to surface tension ?
6. Obtain the dimensions of coefficient of viscosity.
7. Define coefficient of diffusion and give its unit and dimensions.
8. Bring out the similarities between the laws of osmotic pressure and perfect gas laws.
9. Define the term effusion of gases.
10. What are isotropic and anisotropic solids ?
11. Define temperature gradient.
12. Define volume coefficient of a gas.
13. Find the efficiency of a Carnots engine working between 127C and 27C.
14. Define entropy. What happens to entropy of reversible and irreversible processes ?
15. State first law of thermodynamics.
Answer ALL questions.
All questions carry equal marks.
16. (a) Derive an expression for bending moment.
(b) Describe the method of determination of Youngs modulus of a bar by vibration method.
17. (a) Describe Ostwald viscometer. How it is
used to compare the viscosities of two liquids ?
(b) A liquid drop of radius R breaks up into 64 small drops. Calculate the change in energy.
18. (a) What is osmotic pressure ? Describe an
experiment to measure the osmotic pressure of a give solution.
(b) State Ficks law of diffusion and explain their analogy to laws of heat conductions.
Answer any THREE questions.
All questions carry equal marks.
21. Describe Konigs method for the determination of Youngs modulus of abeam with necessary theory.
22. Describe with necessary theory, the Rankines experiment for the measurement of the viscosity of a gas.
23. Deduce the relation between the osmotic pressure and the elevation of boiling point of a solution. Explain how the molecular weight of the solute can be determined from the elevation of the boiling point.
24. Give the theory of cylindrical flow of heat. Describe an experiment to find the coefficient of thermal conductivity of rubber.
25. Write an essay on principle and function of air - conditioners.
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| Earning: Approval pending. |
