Quiznetik

Heat Engines | Set 4

1. Engines are supercharged

Correct : B. To increase specific power output

2. Thermodynamic equilibrium is completely defined by the specifications of the

Correct : D. All above together

3. Within the boiler the temperature of steam is highest in

Correct : C. Superheater outlet

4. A closed vessel contains air at 1.2 ata and 57?C. The pressure of air in the vessel if the contents of the vessel are cooled to 37?C would be

Correct : B. 1.127 ata

5. Which one of the following acts as ignition accelerator for C.I. engines fuel

Correct : A. Acetone peroxide

6. Paraffins in petrol have the general formula

Correct : B. Cn H2n + 2

7. If an air cooled compressor gets over-heated during operation, the probable cause cannot be

Correct : C. Leadage in intercooler

8. The phenomenon of hunting is associated with

Correct : A. Governors

9. The term regeneration is closely associated with

Correct : B. Steam turbines

10. The air standard efficiency of a turbine cycle is 56.5%, which one of the following may be Carnot efficiency between the temperature limits of the cycle?

Correct : B. 64%

11. A wankel engine is

Correct : A. Rotory engine

12. The temperatures and pressures for boiler are given below. Which of these boilers can be classified as super-critical pressure boiler?

Correct : E. 218 kg/cm2, 540?C

13. Motor cycle not using deflector type piston usually utilise

Correct : A. Reverse flow scavanging

14. Direction of feed water is done because

Correct : C. It reduces corrosion caused by oxygen present in air

15. The dryness fraction of steam within a turbine is usually not allowed to fali below

Correct : D. 0.9

16. Which of the following is an accessory for a boiler?

Correct : D. Feed pump

17. The molecules move in a solid

Correct : B. Back and forth like tiny pendulum

18. In all a four stroke four cylinder engine will have how many valves?

Correct : A. 8

19. Latent heat is

Correct : A. Heat required to change the state or condition under which the substance exists

20. Steam consumption per kWh of electricity generated in a modern power plant is of the order of

Correct : B. 5 - 7 kgs

21. In jet engines the compression ratio

Correct : A. Varies with square of speed

22. An Orsat's apparatus is used for

Correct : C. Volumetric analysis of the flue gas

23. Motoring test on I.C. engines is conducted to measure

Correct : D. Friction horse power

24. The turbidity in boiler feed water causes

Correct : A. Sludge

25. Steam leaves the steam nozzle at

Correct : B. Low pressure and high velocity

26. In diesel engines thermal efficiency may be expected in the range

Correct : A. 35 to 40 percent

27. In reciprocating air compressor, the method of controlling the quantity of air delivered is done by

Correct : D. All of the above

28. Motor cycles generally have

Correct : E. Air cooled engines

29. Crankcase dilution is

Correct : B. Dilution of lubricating oil in crankcase

30. In an analysis report of a sample of coal the percentage of one of the constituents is specified as 3.5%. This constituent could be

Correct : D. Sulphur

31. A plant costing Rs. 80,000 has a useful life of 12 years. The amount that should be saved annually to replace the equipment at the end of useful life with salvage value of Rs. 8,000 should be

Correct : C. Rs. 6000

32. In a spark ignition engine supercharging

Correct : C. Increases knocking tendency

33. A passout turbine generally operates on low pressure in the range

Correct : A. 10 - 20 kg/cm2

34. In a reaction turbine while steam flows through the fixed blades

Correct : C. Velocity increases while pressure drops

35. For steam engine having a throttle governor, a straight line is obtained when the total weight of steam used per hour is plotted against the indicated horse power. This line is known as

Correct : A. Willian's line

36. Ignition accelerators are used primarily to

Correct : C. Reduce combustion knock

37. A gas turbine power plant suits as

Correct : A. Peak load plant

38. In diesel engines, the accumulation of carbon in the cylinder increases

Correct : D. Effective compression ratio

39. Which of the following is the internal loss of a turbine?

Correct : B. Blade friction loss

40. Which of the following is not a property of carbondioxide?

Correct : D. Pungent odour

41. A heat exchanger that can remove fixed quantity of heat from a system is available where should it be installed for best economy

Correct : E. Prior to first stage compression

42. A fan is being operated in an environment for which information is available. Now if the fan speed is doubled, how will the static pressure vary

Correct : E. Four times

43. A 50 cfm compressor can

Correct : A. Compress 50 cu feet per min of free air

44. A perfect heat engine works on the Carnot cycle between 1000?C and 200?C. The efficiency of the engine will be

Correct : C. 62.80%

45. A gas turbine works on

Correct : B. Brayton cycle

46. In power station practice 'spinning reserve' is

Correct : B. Reserve generating capacity that is connected to bus and ready to take load

47. Ash content of a diesel fuel oil should not exceed

Correct : D. 0.01%

48. Injector is used to

Correct : D. Inject water boiler

49. A barn is a

Correct : C. Unit of area

50. High steam and low water safety valve is not used on which of the following boiler?

Correct : A. Locomotive boiler

51. Change in internal energy is least during

Correct : E. Isothermal process

52. Which of the following is not a petroleum product?

Correct : A. Methylated spirit

53. Thermal efficiency of a standard Otto cycle for a compression ratio 5.5, will be

Correct : E. 50%

54. The calorific value of methane can be determined by

Correct : E. None of the above

55. The fact that the product of pressure and volume of a fixed amount of gas is approximately a constant value is known as

Correct : E. None of the above

56. Air fuel ratio for a jet engine is of the order of

Correct : A. 60;1

57. A steam nozzle is said to be choked when

Correct : E. Pressure at throat is less than the exit pressure

58. In a four stroke cycle the minimum temperature inside the engine cylinder occurs

Correct : B. At the end of suction stroke

59. According to Charle's law

Correct : A. At constant pressure the volume of a gas is proportional to its absolute temperature

60. Prony brakes are used for testing

Correct : D. Small engines

61. In wet dry lubrication of diesel engines

Correct : C. Oil is pumped to various points

62. In a velocity compounded impulse turbine, while steam flows through the second row of moving blades

Correct : B. The velocity reduces

63. Ignition accelerators are often used for

Correct : B. Petrol engine fuels

64. Which one of the following statements is incorrect

Correct : D. All of the above

65. During idling in a compression ignition engine the air fuel ratio may be of the order of

Correct : E. 30

66. Solid injection in diesel engines implies

Correct : E. Injecting fuel without air

67. Which fuel has maximum resistance to detonation

Correct : D. Iso-octane

68. The level of oil in engine cylinder should be checked when the engine is

Correct : A. Not running

69. The molecular weight of a mixture containing 20% oxygen, 20 percent nitrogen and 60 percent carbon dioxise on volume bases will be nearly

Correct : A. 38.4

70. Dissociation is

Correct : B. Same is combustion

71. Thermodynamic processes are those

Correct : A. Where a difference is observed in any macroscopic property of the system between different times or state

72. A Lungistrom turbine is a

Correct : A. Radial flow reaction turbine

73. Highest useful compression ratio is the compression ratio at which

Correct : D. Detonation first becomes audible

74. The pour point of diesel fuel oil must be

Correct : C. Less than the coldest atmospheric temperature of which oil is to be pumped

75. The emission of carbon monoxide in automobile exhaust will be low when the vehicle is

Correct : D. Cruising at high speeds

76. In a four stage compressor system first and third stage pressures are 1 and 9 kg/cm2 respectively. What will be the fourth stage delivery pressure

Correct : B. 81 kg/cm2

77. In a lead cell battery the voltage per cell is

Correct : D. 2 volts

78. Ignition quality of diesel fuel is expressed by

Correct : B. Cetane number

79. The use of Wilson's line for flow calculation is associated with

Correct : D. Steam-nozzles

80. Rateau turbine is a

Correct : D. Pressure compounded impulse turbine

81. Centrifugal blowers can supply

Correct : A. Large volumes of air at low pressures

82. To augment the thrust of jet propulsion units part of the fuel is burned in the exhaust. How does this fuel burn

Correct : E. Fuel finds oxygen from excess air supplied to engine

83. Intake air filters are provided on air compressor for

Correct : A. Removing dirt and dust from suction air

84. Which one of the following factors will not assist in getting high power output from a compression ignition engine

Correct : D. Large quantity of excess air

85. The lowest temperature upto which a mercury thermometer can be used is

Correct : A. ? 39?C

86. In case of a condensing turbine the pressure in the last stage of the turbine is

Correct : D. Less than the atmospheric pressure

87. The blades of a turbine are made of

Correct : D. Nickel alloy

88. The frictional horse power of a well adjusted petrol engine should be nearly

Correct : E. 10%

89. LPG stands for

Correct : A. Liquefied petroleum gas

90. The term scavanging is generally associated with

Correct : D. Two stroke engines

91. Solubility of a gas in a liquid at small concentration is represented in

Correct : A. Henry's law

92. The engine provided on scooters is generally

Correct : D. Two stroke, air cooled

93. The instrument used for the measurement of area of p-v diagram is known as

Correct : C. Planimeter

94. If in a compression ignition engine the noise level is to be reduced, the design features which will not be affected are

Correct : D. Fuel injection equipment

95. For dry saturated steam the value of adiabatic index n is taken as

Correct : A. 1.135

96. In a petrol engine the mixture strength for maximum power is

Correct : E. 1 ; 13

97. The main purpose of compounding in case of steam turbines is to

Correct : D. All of the above

98. Which of the following is not the same as watt?

Correct : B. Amperes/volt

99. In an engine radiator, heat is transferred by

Correct : D. Conduction and convection

100. A rich mixture will have an air-fuel ratio

Correct : A. Less than chemically correct