Quiznetik

Heat Engines | Set 5

1. The self-ignition temperature of diesel oil as compared to petrol is

Correct : A. Higher

2. Rank of coal is based on

Correct : A. Fixed carbon and heating value

3. Piston rings are made of

Correct : E. Cast iron

4. This purpose of supercharging an engine is

Correct : A. To increase the power output of engine

5. The lowest temperatures that can be measured by a gas thermometer using nitrogen is

Correct : C. ? 200?C

6. Gusset stays are provided in

Correct : D. Boilers

7. One kg of octane is burnt by four alternative processes given below. In which case the work available will be maximum?

Correct : D. When burnt in a reversible process

8. For superheated steam in a nozzle the critical pressure ratio is

Correct : B. 0.546

9. Dark, black smoke from diesel engines usually results when the engine is

Correct : D. Running at full load and full speed

10. A starting motor should have capacity to generate power equal to

Correct : D. Friction horse power at cranking r.p.m

11. Water gas is a mixture of

Correct : B. CO and H2

12. A jet engine has

Correct : D. No propeller

13. A Lenoir cycle has a top temperature in the cycle

Correct : D. Between Otto and diesel cycles

14. In isochronous governors the speed drop is

Correct : E. Zero

15. In a Diesel engine the duration between the time of injection and time of ignition is called

Correct : B. Delay period

16. All but one of the following possible steam generator test difficulties would cause the apparent performance to be poorer than it actually is. One item would make the performance look better than it really is. Identify the item

Correct : D. Coad scales are inaccurate, reading high

17. Resilience is the property of materials in which

Correct : B. Materials spring back or recoil when pressure is removed

18. Thermie

Correct : A. Is quantity of heat required to raise temperature of one tonne of water from 14.5?C to 15.5?C

19. Induced draft fan for a boiler is always located

Correct : B. At the foot of the chimney

20. Intercooling in multistage compressors is done

Correct : E. To minimise the work of compression

21. Which of the following is an important consideration in the design of turbine blades?

Correct : A. Creep

22. Sensible heat is

Correct : C. That heat which produces a rise of temperature

23. The effieincy of a diesel cycle increases with

Correct : B. decrease in cut off

24. In a throttle governed steam engine

Correct : D. Admission pressure is varied while cut off remains unaltered

25. For gas turbines compressors used are

Correct : C. Axial flow type

26. How many kg of air will contain one kg of oxygen?

Correct : C. 4.35 kg

27. Vapour lock is

Correct : B. Serious restriction to the supply of fuel due to excessively rapid formation of vapour in S.I. engine

28. Which of the following part is not common between a steam engine and a petrol engine?

Correct : D. Muffler

29. The efficiency of a jet engine is higher at

Correct : A. Higher altitudes

30. Which of the following is a false stagement: The cause of excessive engine vibrations especially at high speeds in spark ignition engines is

Correct : A. Unequal distribution of mixture

31. In regenerative feed heating system the steam 'bled' from turbine exchanges heat with

Correct : D. Feed water for boiler

32. In thermodynamics spontaneous processes are those

Correct : C. Which occur in the direction of an intensive property or driving force contained within the system

33. Which one of the following is not a constituent of coal

Correct : B. Manganese

34. The gas used for cooling the conductors of large generators is

Correct : E. Hydrogen

35. During preliminary test run of an engine for 7 hours cycles if the engine stops after operating for 5 hours then

Correct : B. The engine is again run for 7 hours

36. Prony brake is used for testing of

Correct : C. Small engines

37. The missing quantity in a steam engine can be reduced by all of the following methods EXCEPT

Correct : C. Reducing the speed of the engine

38. In the Bomb calorimeter the fuel to be tested is burned

Correct : C. At constant volume

39. The maximum horse power of a 150 CC scooter engine is around

Correct : D. 8

40. Boilers using Bagasse as fuel use

Correct : E. Spreader stokers

41. The enthalpy of vaporisation is minimum at

Correct : B. Critical temperature

42. Which part of a gas turbine is subjected to the highest temperature?

Correct : A. Blades

43. In case of glass tube type water level indicator for a boiler

Correct : A. One end of the tube is connected to water space and the other is connected to steam space in the drum

44. Baffles are provided on engines to

Correct : B. Improve heat transfers rate

45. A rope brake dynamometer falls under the category of

Correct : C. Mechanical friction type dynamometer

46. Live storage of fuel means

Correct : A. Fuel stored to meet day's requirement for the boiler

47. In closed cooling system

Correct : A. Hot water is recirculated after cooling

48. In a four stroke petrol engine

Correct : B. Intake valve closes after BDC

49. Coking is

Correct : A. In boiler furnace some coal becomes plastic and forms lumps or masses of coke

50. Shock effect in the nozzle generally occurs in

Correct : D. Diverging section

51. Dehydration is the process of removal of

Correct : C. moisture from anything that is wet

52. For minimum work in multistage compression, the work done on

Correct : C. All stage should be equal

53. For the same maximum pressure and heat input the least efficient cycle is

Correct : C. Weight of engine

54. A Curtis turbine is

Correct : A. A velocity compounded readtion turbine

55. If the performance of diesel engines of different sizes, cylinder dimensions and horse power ratings are to be compared, which of the following parameter can be used for such comparison?

Correct : B. Brake specific fuel consumption

56. For same heat input and same compression ratio

Correct : C. Otto cycle is more efficient than Diesel cycle

57. The volumetric efficiency of a well adjusted engine at full load may be

Correct : C. 75 to 95 percent

58. In Ambassador car, the engine is

Correct : A. Multi-cylinder type

59. Dehydration means

Correct : C. Removing water from any matter

60. Absolute pressure is

Correct : D. Gauge pressure + atmospheric pressure

61. Samples of exhaust gases from following engines have been collected

Correct : E. Jet propulsion unit

62. Normally the colour of exhaust from a petrol engine is

Correct : D. Bluish

63. The boilers using lignite as fuel do not use

Correct : E. Underfeed stoker

64. Cetane number of diesel generally used in India is in the range

Correct : B. 40 to 55

65. Scavenging efficiency of a four stroke diesel engine is

Correct : D. Between 100% and 95%

66. The bottom ring on the piston is known as

Correct : A. Oil ring

67. In a compression ignition engine squish is

Correct : D. Created towards the end of compression stroke

68. Which locomotives has the highest unbalanced forces?

Correct : B. Steam locomotives

69. For the same power and same speed, the flywheel of a two stroke engine as compared to that of a four stroke engine will be

Correct : D. Bigger

70. The maximum amount of dissociation occurs in the burnt gases of a

Correct : C. chernically correct mixture

71. In a Carnot cycle the algebraic sum of the entropy changes for the cycle is

Correct : A. Zero

72. Blue smoke from a diesel engine indicates the presence of

Correct : B. Unburnt oil

73. A turbo-charger is used

Correct : B. For supercharging reciprocating engine

74. For same compression ratio and same heat input

Correct : A. Otto cycle is more efficient

75. Which is the external loss in a steam turbine?

Correct : D. Back pressure losses

76. If engines of different horse power, rpm, cylinder dimensions are to be compared for their performance, the parameter of comparison could be

Correct : A. Mean effective pressure

77. Ambassador car engine is

Correct : B. Overhead valve type

78. Which of the following chemical acts as anti-freeze?

Correct : B. Glycol

79. A low pressure accumulator is generally used with which of the following turbine

Correct : A. Mixed pressure turbine

80. Which is not the cause for loss of heat in boiler due to incomplete combustion?

Correct : D. Boiler drum uninsulated

81. Temporary hardness of water is caused by

Correct : A. Bicarbonates of calcium and magnesium

82. Crankcase explosion occurs in

Correct : E. Two stroke SI engines

83. Which of the following offers best resistance to knocking in S.I. engines?

Correct : A. Aromatics

84. Which of the following engine can work on very lean mixture?

Correct : B. Diesel engine

85. Overall thermal efficiency of a thermal power plant is

Correct : C. Product of boiler efficiency, turbine efficiency and generator efficiency

86. In gas and petrol engines thermal efficiency may be expected in the range

Correct : B. 30 to 35 percent

87. A 200 MW generator should be cooled by

Correct : C. Hydrogen

88. Which of the following exists as highest pressure in a diesel engine

Correct : C. Fuel at the time of injection

89. A camshaft is not provided in case of

Correct : A. Two stroke engines

90. The compression ratio in case of a gas turbine is of the order of

Correct : A. 7

91. Corona is generally accompanied by a faint glow and

Correct : E. Hissing noise

92. If after some use the lower part, electrodes and beathing space of a spark plug are found coated by deposits of soot and carbon, the conclusion will be

Correct : E. Spark plug is of too high heat rating

93. As the compression ratio increases the volumetric efficiency of air compressor

Correct : B. Decreases

94. A fan is being used under certain conditions. If the fan speed is doubled the power requirement will be

Correct : A. 8 times

95. A jet engine has

Correct : B. No propeller

96. In jet engines the compression ratio

Correct : B. Varies with square of speed

97. Steam trap is a device that

Correct : A. Allows passage of water but prevents the passage of steam