Quiznetik

Heat Engines | Set 3

1. A radiation pyrometer is used for temperatures

Correct : C. Above 500?C

2. The processes in a Rankine cycle are

Correct : E. None of the above

3. The function of a receiver in compressor installations is

Correct : B. To dempen pulsations or pressure waves incompressor discharge

4. In an analysis report of a sample of coal, the percentage of one of the constituents is specified as 2.5%. This constituent could be

Correct : D. Sulphur

5. Apart from reducing friction and cooling the surfaces, the function of lubricant in I.C. engines is

Correct : B. To clean the surfaces by carrying away the carbon and metal particles cansed by wear

6. During throttle governing of steam engines

Correct : C. Thermal efficiency of the engine reduces

7. The efficiency of jet engine is higher at

Correct : B. Higher altitude

8. In a compression ignition engine the fuel consumption will increase if the back (exhaust) pressure is

Correct : B. Increased

9. If petrol is supplied to a diesel engine

Correct : D. The engine will run with high knocking

10. A sample of water having pH value of 7 is

Correct : C. Neutral

11. Which of the following has the lowest pressure in a petrol engine?

Correct : D. Mixture at the end of suction stroke

12. The discharge of hydrocarbons from an automobile exhaust is minimum when the vehicle is

Correct : E. Idling

13. Load curve is the plot of

Correct : C. Load versus time

14. With reference to a safety valve the blow down pressure is the pressure at which

Correct : B. Valve closes after opening

15. A four wheel drive automobile has

Correct : E. Two differentials

16. The work done in compressing 1 kg of air in compression will be least when the value of index is

Correct : B. 1

17. Separators are generally used in air compressor installations

Correct : A. Between after cooler and receiver

18. For the same maximum pressure and heat input, the most efficient cycle is

Correct : C. Brayton

19. In compression ignition engines swirl is

Correct : B. Circular motion imparted to suction air

20. Which of the following acts as a step up transformer in the ignition circuit of a petrol engine?

Correct : A. Battery

21. Tidal power is the power generated from

Correct : C. Rise and fall tides

22. Percentage improvement in power in case of a four stroke diesel engine with the help of a supercharger may be expected in the range

Correct : C. 75

23. Thermal efficiency of a spark ignition engine at full load usually is in the range

Correct : A. 30 to 35 percent

24. A Lungistrom turbine is

Correct : C. Outward radial flow turbine

25. Diesel engine has air fuel ratio of 30 ; 1 during idling. A petrol engine can also work on such mixture provided

Correct : C. Dannot run as it is impossible

26. The amount of exhaust gases in clearance space left after exhaust stroke, varies with

Correct : D. Speed and load of the engine

27. Out of the following diesel engine the minimum air consumption per B.H.P. will be in

Correct : E. 4 stroke, mech, injection

28. Enthalpy of a substance is defined as

Correct : C. Total heat content of substance above zero degree centigrade

29. Endurance test for I.C. engines is conducted for

Correct : C. 500 hours

30. A system having connected load of 100 kW, peak load of 80 kW, base load of 20 kW and average load of 40 kW will have a load factor of

Correct : E. 50%

31. The value of reheat factor in case of steam turbines is usually

Correct : B. 1.02 to 1.06

32. A fuel of octane rating 85 matches the antiknock qualities of mixture consisting of

Correct : B. 85% octane + 15% heptane

33. A Wankel engine combines the advantages of

Correct : D. Rotory and reciprocating engines

34. Willian's line is relevant to

Correct : A. Throttle controlled trbine

35. Starting motor in automobiles is generally

Correct : E. Series motor

36. Three states of matter are distinguished with repect to molecules by

Correct : A. Characteristics of the motion of molecules

37. Tenacity is the property of materials in which they

Correct : B. Resist rupture

38. The horse power of engine for a ship is of the order to

Correct : A. 10,000 to 40,000

39. As the steam flows in a subsonic nozzle, in which the cross-section is decreasing in the direction of flow

Correct : D. The velocity will increase while pressure will decrease in the direction of flow

40. White smoke from a diesel engine can be expected during

Correct : A. Start up or idling

41. Total sulphur content in a diesel fuel oil must not exceed

Correct : D. 0.50%

42. Air consumption of a four-stroke diesel engine per rated BHP/hr will be

Correct : C. 5 - 7 kg

43. In spark ignition engines the knocking tendency decreases

Correct : A. As compression ratio is reduced

44. Water and sediments in a diesel fuel oil must not exceed.

Correct : E. 0.05%

45. Rankine cycle efficiency for fixed steam temperature of any volume upto critical temperature will be maximum for steam pressure of

Correct : D. Critical pressure

46. A certain gas occupies 2 cu-m at a temperature of 400?C. It receives heat at constant pressure till its temperature is doubled. The change in volume would be

Correct : E. 3.188 cu-m

47. If the power factor of an electrical system is unity, it means

Correct : C. Entire power pulls the load

48. A fixed quantity of heat is to be added to a system under specific conditions. The process in which the entropy change will be maximum is

Correct : C. Constant temperature process

49. Air standard efficiency of an I.C. engine depends on

Correct : A. Compression ratio

50. Which of the following is false statement?

Correct : D. Fuel consumption increases if lean mixture is supplied

51. Which of the boiler provides superheated steam?

Correct : A. Locomotive boiler

52. Which of the following particles will be smallest in size?

Correct : C. Smog

53. Dew point temperature is an indication of

Correct : D. Lowest temperature where air and water vapour start separating

54. High air-fuel ratio in gas turbines

Correct : A. Reduces the exhaust temperature

55. If a steam injector fails to lift the water the trouble may not be due to

Correct : C. Water supply to cold

56. Working in the cryogenic range means dealing with temperatures

Correct : C. Between - 190?C and absolute zero

57. The sulphur content in diesel oil should not exceed

Correct : D. 1%

58. Which of the following will not be seen in a boiler using pulverised fuel?

Correct : A. Chain in great stoker

59. The governor for steam turbine is driven by

Correct : A. Main shaft

60. Air preheater in a boiler will be invariably located between

Correct : E. Forced draft fan and furnace

61. A run-of-river hydro-electric station is one which is

Correct : C. Located on a steam flow without water storage

62. After cooler is used to

Correct : A. Cool the air

63. Brayton cycle cannot be used in reciprocating engines even for same compression rations and work output because

Correct : A. Large volume at low pressure cannot be efficiently harded in reciprocating engines

64. A sample having pH value of 5 will be

Correct : B. Acidic

65. The mean effective pressure of a diesel cycle having fixed compression ratio will increase if cut off ratio will

Correct : A. Increase

66. Thermal efficiency of C.I. engines on weak mixtures is

Correct : A. Higher

67. In order to achieve maximum possible fuel economy the design features which will be affected are

Correct : D. Atomization

68. A negative loop in the P-V diagram of a petrol engine is due to

Correct : D. early opening of exnaust valve

69. A compound pressure gauge measures

Correct : B. Positive and negative pressures

70. A barN is

Correct : A. A unit of area

71. In isothermal compression

Correct : A. There is no gain internal energy

72. In Parsons reaction turbine

Correct : A. The fixed and moving blades are identical

73. For combustion of one kg of carbon the quantity of oxygen required (air contains 23% by wight of oxygen) is

Correct : C. 2.62 kg

74. If a engine working on Otto cycle has its compression ratio raised from 5 to 6 the percentage increase in air standard efficiency will be

Correct : A. 4%

75. For spark ignition engines fuel in order of decreasing knock tendency are

Correct : B. Paraffins, naphthenes, armatics

76. Which of the following can have octane rating of more than 100?

Correct : D. Benzol

77. Normally the colour of exhaust from a diesel engine is

Correct : D. Black

78. For initially dry and saturated steam flowing through a nozzle the volue of critical pressure ratio is given by

Correct : A. 0.577

79. Which of the following type of internal combustion engines uses rocker arms?

Correct : C. Overhead valve engines

80. In naturally aspirated engine the pressure inside cylinder at the end of suction stroke is

Correct : A. Less than atmospheric

81. The ash content in diesel oil should not exceed

Correct : D. 0.01%

82. A hot short metal is

Correct : A. Brittle when heated

83. In a SI engine the advancing of spark timing will

Correct : A. Increase knocking tendency

84. Of the calorific value ranges given below which one is generally for coal?

Correct : C. 4000 - 7000 kcal/kg

85. The function of a piston rins in an internal combustion engine is

Correct : D. All of the above

86. Zeroth law of thermodynamics states that

Correct : C. If two systems are in thermal equilibrium with a third system, then they are in equilibrium with each other

87. For the same peak pressure and heat input

Correct : B. Diesel cycle is more efficient

88. In a jet propulsion unit the products of combustion after passing through the gas turbine are discharged into

Correct : E. Discharge nozzle

89. A D-slide valve is used in

Correct : D. Steam engines

90. The Clapeyron equation is applicable for

Correct : C. Change of state when two phases are in equilibrium

91. Speed drop is the

Correct : C. Reduction in engine speed from no loads to full load

92. For reciprocating air compressor the law of compression desired is isothermal and that may be possible by

Correct : B. very low speeds

93. In a surface condenser near to the air pump suction the vacuum is 500 mm of mercury with 730 mm of mercury height in a barometer. The pressure near the air pump suction would be

Correct : A. 0.69 kg/sq-cm

94. Which of the following fuel can be obtained by fermentation of vegetable matter?

Correct : A. Alcohol

95. If performance of SI engines of different manufacture having different capacities, sizes and systems are to be compared the common parameter would be

Correct : E. Mean effective pressure

96. Which of the following is not a part of diesel engine?

Correct : D. Condenser

97. Compression ratio for spark ignition engines varies in the range

Correct : A. 6 to 12

98. If a heat engine given an output of 3.5 kW and input is 10000 Joules per second, the thermal efficiency of the engine will be

Correct : B. 35%

99. Inlet valve of a IC engine remains open for

Correct : B. 250?

100. The capacity of an automobile battery is expressed in terms of

Correct : C. Ampere hours