Following are some of the multiple choice questions on the Engineering thermodynamics with answers that will help the students in developing their knowledge.
Engineering thermodynamics MCQ
1. Rankine cycle efficiency of a good steam power plant may be in the range of
2. The efficiency of an ideal Carnot engine depends on
3. Which of the following contributes to the improvement of efficiency of Rankine cycle in a Thermal Power Plant?
4. A regenerative Rankine cycle may approach efficiency of a Carnot cycle between sametemperature by
5. The temperature of feed water can be increased in following two ways in a regenerative Rankine cyclei) by passing feed water around turbine casing in direction opposite to flow of steamii) by bleeding certain portion of steam at the end of h.p expansion & mixing with condensate to make feed water at the temperature of boiler
6. The____________obtainable from a certain heat input in a cyclic heat engine is called
7. Efficiency of a heat engine is defined as
8. The universal gas constant will be equal to difference between specific heats at constant pressure & constant volume for
9. Air expands from initial condition of p1, v1 to final condition of 1/2 p1, 2v1.Choose the correct statement
10. Steam enters the turbine at 5.44 bar with dryness fraction of 0.9 & is expanded adiabatically to a pressure of 0.68 bar. It will enter the condenser with a quality very close to
11. A power cycle using steam as working fluid consist ofi) constant pressure heat addition ii)adiabatic expansioniii) constant pressure heat rejection & iv) adiabatic compression. The cycle is
12. Which of the following remains constant during an adiabatic expansion
13. According to Carnot’s theorem, all heat engines operating between a given constant temperature source and sink, none has a higher efficiency than a reversible engine.
14. Relative humidity is defined as
15. The efficiency and work ratio of a simple gas turbine cycle are
16. In a steam power plant which cycle requires two or more feed pumps
17. The entropy __________ in an irreversible cyclic process.
18. Which of the following is an example of high grade energy?
19. Processes inside a thermal energy reservoir are quasi-static.
20. Entropy principle is the quantitative statement of the second law of thermodynamics.
21. Which of the following represents the latent heat of vaporization at a particular pressure.
22. Which of the following can be considered as an application of entropy principle?
23. Which of the following processes exhibit external mechanical irreversibility?
24. Which of the following is an example of low grade energy?
25. Which of the following is a type of energy?
26. When considering a finite energy source, its working fluid expands,
27. The superheat or degree of superheat is given by
28. Which of the following exists in a p-V diagram for water?
29. Entropy increase dS of the system can be expressed as
30. Which if the following statements are true for a mechanical energy reservoir(MER)?
31. A pure substance which exists in a single phase has____________independent variables.
32. Water____________on melting and has the fusion curve with a____________slope.
33. The properties of liquid__________with pressure.
34. The slope of sublimation curve is_________the slope of the vaporization curve at triple point.
35. The total entropy of a mixture of gases is the___________of the partial entropies.
36. When humidity ratio of air___________air is said to be dehumidified.
37. At any dbt, the___________the difference of wbt reading below below dbt,______________is the amount of water vapour held in mixture.
38. The optimum reheat pressure for most of the power plants is how many times of the initial steam pressure?
39. Which of the following cycles is used in thermalpower plants?
40. By reducing the condenser pressure in Rankine power plant
41. Essential parts of a power plant operating on aRankine cycle are
42. Most of the fossil fuelbased power plants operate on
43. When unsaturated air flows over a sheet of water in an insulated chamber
44. The degree of saturation is the ratio of
45. The expression which represents the pressure exerted by a gas is
46. An application requires R-12 at −140°C. The triple-point temperature is −157°C. Find the pressure of the saturated vapour at the required condition.
47. At the triple point, l(sublimation) = l(vaporization) – l(fusion).
48. When does a vapour become superheated?
49. The slopes of sublimation and vaporization curves for all substances are
50. The Clausius-Clapeyron equation is given by
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