Quiznetik

Applied Thermodynamics (AT) | Set 1

1. Aim of engine testing is

Correct : D. all the above

2. Heat losses in an engine are indicative of

Correct : A. thermal efficiency of engine

3. Power developed within the cylinder is called

Correct : A. i.p.

4. Power available at output shaft is called

Correct : B. b.p.

5. Mechanical losses in engine equal to

Correct : C. i.p./b.p.

6. Best method to measure indicated mean effective pr (imep) is by

Correct : B. electronic indicator

7. Indicator diagram is used to measure

Correct : A. imep

8. Indicator diagram is the plot of_____on cartesian co-ordinates.

Correct : A. p-v

9. Mechanical indicators are suitable to measure imp in case of

Correct : A. low speed engine up to 1500 rpm

10. If a= net area of diagram in mm², l= length of indicator diagram in cm & k= spring constant in N/m²/m the imp in bar equals

Correct : B. (a/l) x k x 10ˉ⁹

11. Engine indicator is used to measure

Correct : B. imep

12. If work developed by the engine per cycle is W, then the indicated mean effective pr equals to

Correct : B. w / stroke volume

13. Best method to measurement of B.P. is

Correct : C. hydraulic dynamometer

14. Which of the dynamometer cannot be used for measurement of B.P. at high speeds

Correct : A. prony brake

15. Which of the following dynamometer is suitable to measure B.P. of an aircraft

Correct : D. eddy current

16. F.P.______with increase in speed

Correct : A. increases

17. Which is the best way to measure F.P. of an I.C., engine

Correct : B. morse test

18. Willan's line method for determining F.P. is applicable to

Correct : C. both a & b

19. I.P. of engine can be determined by

Correct : B. morse test

20. Increase in F.P. of an engine causes

Correct : D. all the above

21. Morse test in multi cylinder engine is used to determine

Correct : A. mechanical efficiency

22. Which is assumed constant in determining F.P. by Willan's line method.

Correct : C. indicated thermal efficiency

23. The range of mechanical efficiency for automobile is

Correct : C. 70-80%

24. The measurement of frictioned power by Willans line is applicable only to

Correct : A. c.i engine at a particualr speed

25. morse test is applicable only to

Correct : C. multi cylinder c.i engine

26. the most accurate method of determining friction power is by

Correct : D. measurement of brake and indicated power

27. in the air base method of measuring air flow, the air base is provided to

Correct : C. have constant flow

28. the air box/ swept volume ratio should be in the range for single cylinder engine

Correct : C. 500-600%

29. the best method of measuring speed is by

Correct : A. mechanical tachometer

30. flame ionization detector is used for measuring

Correct : A. hc

31. chemilumme scence analyzer is used for measuring

Correct : C. nox

32. non dispersive infrared analyzer is widely accepted instrument for measuring

Correct : B. carbone monoxide

33. if n is theorem, number of power stroke per minute in a four stroke enigne is

Correct : A. n/2

34. if n is the rpm, number of power strokes per min in a two stroke engine is

Correct : B. n

35. mechanical effficiency is the ratio of

Correct : C. brake power to indicated power

36. volumetric efficiency is a measure of

Correct : C. brathing capacity of the engine

37. thermal efficiency varries

Correct : A. inversely as specific fuel consumption

38. the spark timing and combustion rate should be should be such that

Correct : A. one half of the total pressure occurs at tdc

39. indicated power is directly proportional to

Correct : A. air consumption

40. the brake thermal efficiecny of SI engine is in the range of

Correct : B. 25%-35%

41. the boiling point of a four cylinder engine is 30 with all cylinder firing and 20 with one cylindr cut

Correct : B. 0.75

42. The bore and stroke of a single cylinder four stroke engine are 100 mm and 160 mm resp. if the brake torqe is 50NM, the brake mean effective pressure is

Correct : A. 5 bar

43. the volumetric efficiecy of a well disigned engine is the

Correct : D. 75-90%

44. if the performance of SI engine manufacturer having different capacities sizes and system are to be compared , the common parameter would be

Correct : D. mean effective pressure

45. mores test is conducted on

Correct : B. multi cylinder engine

46. endurance test for IC engine is conducted for

Correct : D. 500hrs

47. which of the following factor will not assist in improving thermal efficiency of a compression ignition engine

Correct : D. high surgace to volume ratio

48. which statement is correct

Correct : C. morese test can be conducted only on multicylinder engine

49. rope brake dynamometer falls under the category of

Correct : C. mechanical friction type dynamometer

50. prony brakes are used for testing

Correct : A. small engine

51. which of the following is performed for supercharging of ic engine

Correct : B. axial compressor

52. from the engine indicator diagram we obtain

Correct : A. indicatecd mean effective pressure

53. the more accurate dynamometer is

Correct : A. prony brake type

54. the most commonly used dynamometer on account of its simplicity of construction is the

Correct : A. brake type

55. brake mean effective pressure in an engine depends upon its

Correct : B. torque only

56. brake thermal efficiecny of si engine usually varies between

Correct : A. 25-30%

57. the brake power is the

Correct : A. power availabale at the output of the shaft

58. the total power developed by the combustion of the fuel is

Correct : B. ip

59. mean effective pressure is the pressure

Correct : B. which is acting on the piston through out the power stroke

60. fuel air ratio is

Correct : D. all of the abov e

61. specific fuel consumption is

Correct : A. amount of fuel consumed per unit power developed per hour

62. heat balance sheet indicates

Correct : B. brake up of the total energy input in to different parts

63. the frictional power is

Correct : B. bp-ip

64. identify the correct statement

Correct : B. lower friction means high barke power

65. power out put of an engine can be increased by

Correct : D. all of the above

66. power out put of an engine can be increased by

Correct : D. all of the above

67. increasing the power out put by increasing the compression ratio is limited by

Correct : D. hucr

68. increase in speed to improve B.P is limited by

Correct : D. all of the above

69. utilization of energy in exhaust gases causes power output to

Correct : A. increases

70. increase in charge density will

Correct : C. both a & b

71. supercharging is a process of increasing the

Correct : D. charge density

72. supercharging is essential for

Correct : C. aircraft engine

73. power out put of static engine at high alitude compared to power out put at sea level is

Correct : D. can not predict

74. objective of superchargin are

Correct : D. all of the above

75. which is not the objectve of supercharging

Correct : B. to increase weight to power ratio

76. an exhaust gas driven blower/ compressor to increase charge density is called

Correct : D. none of the above

77. a blower/compressor driven by engine shaft to increase charge density is called

Correct : D. none of the above

78. power out put of an engine compared to turbocharge is

Correct : C. less

79. which is not a supercharger

Correct : D. pump

80. compressed air of turbochar is cooled in aftercooler before supply to engine because it

Correct : D. both b and c

81. efficiency of turbocharged engine compared to naturally aspirated engine is

Correct : D. can not predict

82. a free piston engine has

Correct : D. gear driven supercharger and separate power turbine

83. Reason for not using very high suction pressure in an engine with the help of supercharger / turbocharger are

Correct : D. all of the above

84. Reason for not using very high suction pressure in an engine with the help of supercharger / turbocharger are

Correct : D. all of the above

85. superchargin is usually is not employed in si engine in the following cases

Correct : A. static or mobile enigne

86. superchargin in ci engine is limited by

Correct : C. load on bearing and fuel economy

87. A theory in which chain carriers are formed in one step and destroyed in the next step relate to the theory of combustion as

Correct : B. chain reaction theory

88. Time interval between instant the spark is given and the point a tiny flame appears is called

Correct : D. either \a\ or b\

89. Angle tuned by crank between the point of spark and formation of flame is called

Correct : C. ignition delay angle

90. In a vertical engine, the crank angle before TDC at the instant spark is given is called

Correct : D. angle of spark advance

91. The travel of flame speed (m/s) in the S.I. combustion chamber is approximately

Correct : B. 15 to 35

92. Ignition lag in S.I. engine reduces due to

Correct : D. both a and c

93. Minimum ignition lag is obtained when

Correct : A. rich mixture(5 to 10%)

94. Ignition delay period with increase in speed

Correct : C. remains same

95. Ignition delay angle________with increase in speed

Correct : A. increases

96. The speed of the flame propagation increases with increase in

Correct : D. all of the above

97. Increase in turbulence________the flame speeds

Correct : A. increases

98. Increase in speed of the engine________the flame speeds

Correct : A. increases

99. Increase in the size of similar engines__________the crank angle turned during flame travel across the cylinder

Correct : C. doesn\t affect

100. Flame speed in combustion chamber during flame travel are

Correct : B. low at beginning and end and high in the middle