Saturday, 15 October 2016


1. Define term (i) stress (ii) strain
2. Differentiate the properties plasticity and elasticity of material
3 Draw stress - strain curve for elastomers (elastic tissue of Aorta)
4. How are we able to break a wire by repeated bending?
5. What is the value of bulk modulus for an incompressible liquid?
6. Define Poisson’s ratio? Does it have any unit?
7. What is elastic fatigue?
8. Why is it easier to swim in sea water than in the river water?
9. Railway tracks are laid on large sized wooden sleepers. Why?
10. The dams of water reservoir are made thick near the bottom. Why?
11. Why is it difficult to stop bleeding from a cut in human body at high altitude?
12. The blood pressure in human is greater at the feet than at the brain.Why?
13. Define coefficient of viscosity and write its SI unit.
14. Why machine parts get jammed in winter?
15. Why are rain drops spherical?
16. Why do paints and lubricants have low surface tension?
17. What will be the effect of increasing temperature on (i) angle of contact
(ii) surface tension.
18. For solids with elastic modulus of rigidity, the shearing force is proportional to shear strain. On what factor does it depend in case of fluids?
19. How does rise in temperature effect (i) viscosity of gases (ii) viscosity of liquids.
20. Explain why detergents should have small angle of contact?
21. Write the dimensions of coefficient of viscosity and surface tension.
22. Obtain a relation between SI unit and cgs unit of coefficient of viscosity.
23. Explain, how the use of parachute helps a person jumping from an aeroplane.
24. Why two ships moving in parallel directions close to each other get attracted?
25. Why the molecules of a liquid lying near the free surface possess extra energy?
26. Why is it easier to wash clothes in hot water soap solution?
27. Why does mercury not wet glass?
28. Why ends of a glass tube become rounded on heating?
29. What makes rain coats water proof?
30. What happens when a capillary tube of insufficient length is dipped in a liquid?
31. Does it matter if one uses gauge pressure instead of absolute pressure in applying Bernoulli’s equation?
32. State Wein’s displacement law for black body radiation.
33. State Stefan Boltzmann law.
34. Name two physical changes that occur on heating a body.
35. Distinguish between heat and temperature.
36. Which thermometer is more sensitive a mercury or gas thermometer?
37. Metal disc has a hole in it. What happens to the size of the hole when disc is heated?
38. Name a substance that contracts on heating.
39. A gas is free to expand what will be its specific heat?
40. Is the bulb of a thermometer made of diathermic or adiabatic wall?
41. What is the absorptive power of a perfectly black body?
42. At what temperature does a body stop radiating?
43. If Kelvin temperature of an ideal black body is doubled, what will be the
effect on energy radiated by it?
44. In which method of heat transfer does gravity not play any part?
45. Give a plot of Fahrenheit temperature versus Celsius temperature
46. Why birds are often seen to swell their feather in winter?
47. A brass disc fits snugly in a hole in a steel plate. Should we heat or cool the system to loosen the disc from the hole.