Linx Refresher Review
IPD PPD REFRESHERS TRIVIA EXAMINATION
(Linx Refreshers Trivia Examination)
Prepared by: Engr. Jose R. Francisco, PME
August 2012
MULTIPLE CHOICE QUESTIONS
INSTRUCTION: Select the correct answe
...
Linx Refresher Review
IPD PPD REFRESHERS TRIVIA EXAMINATION
(Linx Refreshers Trivia Examination)
Prepared by: Engr. Jose R. Francisco, PME
August 2012
MULTIPLE CHOICE QUESTIONS
INSTRUCTION: Select the correct answer for each of the following questions. Mark only one answer for each item by shading the box
corresponding to the letter of your choice on the answer sheet provided. STRICTLY NO ERASURES ALLOWED. Use pencil No. 1 only.
1. A vertical cylindrical tank contains water. What is the pressure inside at the depth of 8 m?
a) 78.45 kPa b) 75.84 kPa c) 84.75 kPa d) 85.47 kPa
2. A fan is designed to deliver 750 m3/hr with a static head of 50 mm of water on full delivery. Determine the fan static power, in Hp.
a) 0.102 Hp b) 0.317 Hp c) 0.137 Hp d) 0.120 Hp
3. Air taken from the atmosphere at 101 kPaa and 21 oC is delivered to the air receiver at 690 kPaa and 130 oC by means of a water
jacketed reciprocating compressor. The compressor has a rated capacity of 0.20 m3/s free air. What the compressor power input if the
compressor efficiency is 65 %.
a) 79.57 kW b) 77.97 kW c) 75.97 kW d) 97.75 kW
4. Water flows through a pipe at 15 lps. The inlet diameter of the pipe is 120 mm and the exit diameter is 150 mm. If the water is to be
pumped from the source to a height of 8 m and the heat loss is 2 kW, determine the pump brake power.
a) 2.18 kW b) 1.18 kW c) 3.18 kW d) 0.18 kW
5. A centrifugal pump has discharge of 160 lps when operating at 1800 rpm and impeller diameter of 254 mm. Find the new discharge if
the impeller diameter is changed to 203.2 mm while the speed remains constant.
a) 128 lps b) 200 lps c) 218 lps d) 138 lps
6. What horsepower is required to air moving at 30 fpm through a circular duct with a radius of 12 inches under a pressure of 0.5 ft water
gage?
a) 0.089 Hp b) 0.098 Hp c) 0.078 Hp d) 0.069 Hp
7. An industrial fan operating at standard conditions of 1 atmosphere and 21.1 oC requires a brake power of 100 kW at a head of 20 cm
water gage. Determine the new brake power if the fan is to operate in an environment of 97 kPaa and 27 oC at the same speed.
a) 74 kW b) 84 kW c) 94 kW d) 104 kW
8. The piston displacement of a double-acting compressor is 0.358 m3/s, delivers gas from 1 atmosphere and 27 oC to 675 kPaa at the
rate of 0.166 m3/s and 150 rpm. The value of n for compression and re-expansion is 1.33. Determine the compressor percent
clearance.
a) 16.96 % b) 19.66 % c) 15.96 % d) 13.96
9. Determine the specific speed of a centrifugal pump delivering 7500 gpm against a total head of 370 ft and operating at 1000 rpm.
a) 1062.55 rpm b) 1026.55 rpm c) 1055.26 rpm d) 1625.05 rpm
10. A boiler feed pump receives 300 lpm of water at 90 oC (h = 839.33 kJ/kg) and operating against a total head of 800 m. Determine the
enthalpy of water at the pump discharge assuming that the pump efficiency is 70 %.
a) 805.54 kJ/kg b) 850.54 kJ/kg c) 854.05 kJ/kg d) 845.50 kJ/kg
11. The mean effective pressure of an air compressor is 500 kPa. If the compressor work is 150 kW, determine the compressor piston
displacement, in lpm.
a) 18000 lpm b) 300 lpm c) 0.30 lpm d) 900 lpm
12. A two-stage compressor receives 0.35 kg/s of air at 100 kPaa and 269 K and delivers it at 5000 kPaa. Determine the rate of heat
transfer in the intercooler.
a) 70.83 kW b) 80.73 kW c) 83.70 kW d) 78.03 kW
13. An induced draft fan is used to extract 270 000 m3/hr of flue gas from a boiler furnace. The fan is to deliver at a total pressure of 250
mm water gage. Determine the size of electric motor, in kW, if a fan mechanical efficiency of 55 % is used.
a) 340 kW b) 330 kW c) 320 kW d) 370 kW
14. Calculate the impeller diameter of the centrifugal pump that requires 15 m head to deliver water if the pump speed is 1500 rpm.
a) 248 .1 mm b) 218.4 mm c) 281.4 mm d) 241.8 mm
15. The bore and stroke of an air compressor are 276 mm and 164 mm, respectively. If the piston displacement is 0.059 m3//s, Determine
the operating speed of the compressor.
a) 380.6 rom b) 368.0 rpm c) 360.8 rpm d) 386.0
16. The mechanical efficiency and static pressure of a fan are 44.37 % and 20 m of air, respectively. What is the static efficiency if the total
pressure created by the fan is 25 m of air?
a) 34.5 % b) 44.37 % c) 35.5 % d) 45.5 %
17. The fan has a total pressure of 190 m of air and a static pressure of 20 cm water gage. If the air density is 1.20 kg/m3, determine the
velocity of flowing.
a) 21.39 m/s b) 23.19 m/s c) 29.32 m/s d) 22.93 m/s
18. A 5 kW motor is used to drive an air compressor. Determine the compressor theoretical power if the efficiency is 72 %.
a) 6.94 kW b) 3.6 kW c) 4.6 kW d) 4.96 kW
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Linx Refresher Review
19. A single-stage air compressor handles 0.454 m3/s at atmospheric pressure and 27 oC and delivers it to the receivers at 652.75 kPaa.
Its volumetric efficiency is 72 %, its compression efficiency on an isothermal basis is 85 %, and its mechanical efficiency is 90 %. If it
rotates at 350 rpm, determine the power required to drive the compressor.
a) 112 kW b) 100.8 kW c) 85.69 kW d) 121 kW
20. Convert a vacuum pressure of 110 mm Hg into absolute pressure if atmospheric pressure is 10.5 m of water.
a) 9 m H2O b) 11 m H2O c) 8 m H2O d) 12 m H2O
21. A fuel pump is delivering 2.27 m3/hr of oil with a specific gravity of 0.83. How much energy does the pump consumes, in kJ/hr if the
total head is 9.14 m?
a) 186.88 kJ/hr b) 168.88 kJ/hr c) 203.5 kJ/hr d) 188.68 kJ/hr
22. A pump delivers 500 gpm of water against a total head of 200 ft and operating at 1770 rpm. Changes have increased the total head to
375 ft. At what rpm should the pump be operated to achieve the new head at the same efficiency?
a) 2324 rpm b) 3232 rpm c) 2424 rpm d) 2244
23. A fan whose static efficiency is 40 % has a capacity of 16.67 ft3/s at 60 oF and barometer of 30 inches of Hg and gives a static pressure
of 2 inches of water column on full delivery. What size of electric motor shall be used to this fan?
a) 0.75 Hp b) 1 Hp c) 0.80 Hp d) 0.90 Hp
24. A ventilating fan discharges 4.4 m3/s through a duct 91 cm in diameter against a static pressure of 22 mm water gauge. Barometer
pressure is 730 mm Hg, the temperature of air 29.44 oC and gauge fluid density is 994 kg/m3. If the power input is 2.65 kW, determine
the static efficiency.
a) 35.82 % b) 89.37 % c) 40.08 % d) 42.82 %
25. A two-stage air compressor at 90 kpaa and 20 oC discharges at700 kPaa. Find the polytropic exponent n if the intercooler intake
temperature is 100 oC.
a) 1.308 b) 1.380 c) 2.4 d) 1.25
26. Determine the resulting pressure when one kilogram of air at 103 kPaa and 95 oC is heated at constant volume to 425 oC.
a) 205.36 kPaa b) 195.35 kPaa c) 196.35 kPaa d) 193.56 kPaa
27. What is the amount of heat added to 15 kg of air to increase its temperature from 30 oC to 250 oC without changing the pressure?
a) 3230.46 kJ b) 3420.26 kJ c) 3320.46 kJ d) 3640.36 kJ
28. Find the change of specific internal energy of air when heated fro 30 oC to 300 oC.
a) 419 kJ/kg b) 194 kJ/kg c) 149 kJ/kg d) 491 kJ/kg
29. What is the specific gravity of a fuel at 28o Baume?
a) 0.868 0.688 c) 0.886 d) 0.986
30. If the enthalpy of a certain gas is 2400 kJ/kg and its internal energy is 2200 kJ/kg, find the specific volume at a pressure of 950 kPaa.
a) 0.2105 m3/kg b) 0.2501 m3/kg c) 0.2015 m3/kg d) 0.1025 m3/kg
31. Determine the maximum temperature of a Carnot cycle if it operates at a minimum temperature of 20 oC with an efficiency of 60 %.
a) 459.5 oC b) 455.9 oC c) 495.5 oC d) 559.4 oC
32. A Rankine cycle operates with a thermal efficiency of 40 % and the factor of evaporation of the boiler is 1.15. Determine the mass flow
rate of steam if the cycle power output is 5.5 MW.
a) 5.3 kg/s b) 4.3 kg/s c) 3.5 kg/s d) 6.3 kg/s
33. A heat engine operates with a thermal efficiency of 58 %. Determine the engine power output if the rate of heat added is 280 MW.
a) 146.2 kW b) 162.4 kW c) 126.4 MW d) 164.2 MW
34. The percent rating of water tube boiler is 200 %, factor of evaporation is 1.10, and heating surface is 400 ft2. Determine the rate of
evaporation, in kg/hr.
a) 1831 b) 1831 c) 1138 d) 1813
35. A 10 kg/s of air enters the theater at 16 oC. The theater is to be maintained at 27 oC DB and 20 oC WB. If the sensible heat ratio is
0.80, what is the latent heat load of the theater?
a) 27.67 kW b) 26.75 kW c) 110.682 kW d) 72.67 kW
36. Determine the mole fraction of the helium in a mixture of 45 % helium and 55 % nitrogen by mass analysis.
a) 14.84 % b) 85.16 % c) 18.44 % d) 81.56 %
37. A 60 MW power plant has an average load of 34 500 kW and a load factor of 0.75. Find the reserve power over a peak load power.
a) 14 000 kW b) 20 000 kW c) 46 000 kW d) 5 000 kW
38. A steam generator burns fuel oil with 20 % excess air. Fuel may be represented by C14H30. Calculate the actual-air fuel ratio.
a) 17.9 b) 18.7 c) 16.7 d) 15.7
39. A certain coal has the following ultimate analysis by weight. C = 67 %, Ash = 5 %, Moisture = 8 %, N = 6 %, H = 3 %, Sulfur = 7 %, O =
4 %. Calculate the air-fuel ratio if this coal is burned with 50 % excess air.
a) 12.4 b) 13.3 c) 14.3 d) 12.4
40. A container filled with helium is dropped 4 km above the ground, find the change of temperature?
a) 12.6 oC b) 17.5 c) 15.2 oC d) 18.5 oC
41. A turbine has a peripheral coefficient of 0.6. Find the runner diameter of the turbine if it operates at 450 rpm and a head of 60 m.
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Linx Refresher Review
a) 0.874 m b) 0.784 m c) 0.478 m d) 0.748 m
42. A 5 m x 5 m wall of a room has a surface temperature of 40 oC. The wall thickness is 25 cm and has a thermal conductivity of 0.07
W/m-oK, and air film conductance is 15 W/m2-oK. If the outside air temperature is 18 oC, what is the heat loss through the wall?
a) 151.18 W b) 185.18 W c) 158.11 W d) 118.15 W
43. Heat is transferred from hot water to an oil in a double-pipe counter-flow heat exchanger. Water enters the outer pipe at 110 oC and
exits at 45 oC while the oil enters the inner pipe at 24 oC and exits at 62 oC. What is the log-mean temperature difference (LMTD)?
a) 32.66 oC b) 36.62 oC c) 36.26 oC d) 42.66 oC
44. Determine the indicated power of a four-cylinder, 4-stroke, Diesel engine with 20-cm bore and 30-cm stroke running at 1000 rpm and
has a reading of 450 kPa mean effective pressure in the indicator diagram.
a) 159.83 Hp b) 189.53 Hp c) 158.93 Hp d) 198.53 Hp
45. The approach and efficiency of cooling tower are 10 oC and 65 %, respectively. If the temperature of water leaving the tower is 27 oC,
determine the temperature of water entering the tower.
a) 54.57 oC b) 55.47 oC c) 45.57 oC d) 54.75 oC
46. A dryer is to deliver 1000 kg/hr of cassava with 2 % moisture and 20 % moisture in the feed. Determine the mass of air required per
hour if the change in humidity ratio is 0.0165.
a) 16 136.36 kg/hr b) 13 636.36 kg/hr c) 13 163.63 kg/hr d) 16 336.63 kg/hr
47. A scuba diver releases bubbles from the bed of a sea. The bubble reaches the sea water surface with volume of 6 times than it had
when it was released. If the relative density of sea water is 1.03 and thermal equilibrium is observed at all times, compute for the depth
of the sea.
a. 50.2 m b. 25.0 m c. 52.0 m d. 45.2 m
48. A reversed Carnot cycle has a refrigeration COP of 5. What is the ratio Tmax/Tmin?
a) 1.2 b) 2.1 c) 1.3 d) 3.1
49. In a geothermal power plant, the enthalpies of the ground water and the turbine inlet are 1500 kJ/kg and 3500 kJ/kg respectively. If the
enthalpy of the hot water in the flash tank is 700 kJ/kg and the mass flow rate of steam is 15 kg/s, what is the mass flow rate of ground
water?
a) 52.5 kg/s b) 55.2 kg/s c) 25.5 kg/s d) 35.2 kg/s
50. Water is flowing in a pipe with a diameter of 10 inches at a velocity of 5 m/s. If the density is 997.9 kg/m 3 and the viscosity of water is
1.131 Pa-s, determine the type of flow of fluid.
a) Critical flow b) Transitional flow c) Laminar flow d) Turbulent flow
51. The performance of a reciprocating compressor is expressed as:
a) Adiabatic work divided by adiabatic input b) Adiabatic work divided by indicated work
c) isothermal work divided by indicated work d) Isothermal work divided by adiabatic work
52. Which of the following components of a pump converts mechanical energy to pressure energy?
a) Valve b) Impeller c) Shaft d) Delivery pipe
53. Centrifugal blowers can supply:
a) Large volumes of air at low pressures b) Small volumes of air at high pressures
c) Large volumes of air at high pressures d) Small volumes of air at low pressures
54. Nozzle does not involve any work interaction. The fluid through this device experiences:
a) No change in potential energy b) No change in kinetic energy
b) c) No change in enthalpy d) Vacuum
55. Generally, what is the velocity of water flowing through concrete tunnel?
a) 4 to 5 m/s b) 6 to 7 m/s c) 5 to 6 m/s d) 7 to 8 m/s
56. Choking in pipe flow mean that there is a:
a) Restriction in area b) Reduction I opening c) Cavitation d) Non-occurrence of the specified mass flow rate
57. In pump installations, what is referred as the vertical distance from the water supply level to the pump centerline wherein the pump is
above the supply level
a) Discharge head b) Static suction head c) Static suction lift d) Static discharge head
58. The power required to deliver a given quantity of fluid against a given head with no losses in the pump is called as:
a) Wheel power b) Brake power c) Indicated power d) Hydraulic power
59. In a Carnot cycle, heat addition occurs during which of the following processes?
a) Isothermal compression process c) Isentropic expansion process
c) Isothermal expansion process d) isentropic compression process
60. Stirling cycle is also called as:
a) Constant volume regenerative cycle b) Constant pressure regenerative cycle
c) Constant temperature regenerative cycle d) Constant entropy regenerative cycle
61. Ericson cycle is also called as:
a) Constant volume regenerative cycle b) Constant pressure regenerative cycle
c) Constant temperature regenerative cycle d) Constant entropy regenerative cycle
62. It is the generic term given to a family of solid fuels with high carbon content. How do you call this?
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Linx Refresher Review
a) Solid fuel b) Coal c) Anthracite d) Bituminous
63. It is a boiler fuel created from the residue produced from crude petroleum after it has been distilled to produce lighter oils like gasoline,
paraffin, kerosene, diesel or gas oil. What is this fuel?
a) Oil b) Kerosene c) Coke d) Peat
64. What do you call a form of boiler fuel that is easy to burn, with very little excess air?
a) Coal b) Oil c) Gas d) Bunker
65. It defined as energy added to or removed from a system divided by the mean absolute temperature over which the change takes
place. How do you call this?
a) Enthalpy b) Heat energy c) Specific heat d) Entropy
66. The second law of thermodynamics says that whenever energy is exchanged or converted from one form to another, the potential for
energy to do work will be _________.
a) Decreased b) Increased c) Zero d) Stagnant
67. What is true about steam as it condenses?
a) It does so at constant entropy and temperature b) It does so at constant enthalpy and reducing temperature
c) Both enthalpy and entropy reduce and temperature remains constant d) Both enthalpy and entropy increase
68. It is an increase in fluid pressure in a long pipe caused by a sudden velocity decrease, where the sudden decrease in velocity is
caused by a valve closing.
a) Aero dynamics b) Water hammer c) Terminal velocity d) Drag
69. It is an upward force that is exerted on an object (like flat plate, airfoil, rotating cylinder, etc.) as the object passes through a fluid. What
do you call this?
a) Drag b) Lift c) Aero horsepower d) Terminal velocity
70. What is a frictional force that acts parallel but opposite to the direction of motion of fluid?
a) Drag b) Lift c) Aero horsepower d) Terminal velocity
71. It is a term used by automobile manufacturers to designate the power required to move a car horizontally at 50 mi/hr against the drag
force. What is this?
a) Mechanical horsepower b) Aero horsepower c) Fuel power d) Fluid power
72. A manufacturer claims that it has a COP of 2.0 when cooling a food at 5 oC using ambient air at 30 oC as a heat sink. Is the claim of the
manufacturer valid?
a) Yes b) No c) Probably d) It needs experimental verification
73. What can you say about the velocity of fluid at the center of the pipe section?
a) Maximum b) Minimum c) Average d) Zero
74. Continuity equation is applicable to which of the following?
a) Viscous and unviscous fluids b) Compressibility fluids c) Conservation of mass d) Steady and unsteady flows
75. Hygrometer is an instrument used to determine of which of the following?
a) Specific gravity of fluids b) Specific gravity of gases c) Specific gravity of liquids d) Specific gravity of solids
76. At critical point of a pure substance, what is the value of latent heat?
a) Maximum b) Minimum c) Zero d) Below zero
77. Which of the following is a function of a steam nozzle?
a) Converts kinetic energy into heat energy b) Changes internal energy into kinetic energy
c) Converts potential energy into heat energy d) Changes enthalpic energy into kinetic energy
78. If the sensible heat ratio is 0.75, what does it mean?
a) 75 % latent heat and 25 % sensible heat b) 75 % sensible heat and 25 % latent heat
c) 25 % latent and sensible heat and 75 % latent heat d) 75 % sensible and latent heat and 25 % sensible heat
79. The hardness of ground water required as feed water for a boiler is 0 – 10 ppm (part per million), which of the following is the range of
alkalinity requirement?
a) pH 9 to pH 10 b) pH 6 to pH 10 c) pH 10 to pH 11 d) pH 8 to pH 10
80. As used in the Revised PSME Code for Boilers and Pressure Vessels, it is any boiler which does not exceed any of the following limits:
405 mm inside diameter, 1065 mm overall length of outside to outside heats at center, 1.85 m2 of water heating surface, and 7.03
kg/cm2 maximum allowable working pressure. What is this boiler?
a) Power boiler b) Portable boiler c) Miniature boiler d) Locomotive boiler
81. It is a closed vessel in which steam or other vapor (to be used externally to itself) is generated by the direct application of heat used for
power generation. How do you call this boiler?
a) Power boiler b) Portable boiler c) Oil-fired boiler d) Miniature boiler
82. Name one characteristic feature of mechanical steam traps.
a) They pass condensate at steam temperature b) They operate by sensing condensate temperature
c) They can be fitted into any position d) They are not affected by increasing back pressure
83. In a mechanical steam trap, why is a float trap better at venting air than an inverted bucket trap?
a) A float can quickly adjust to the presence of air b) A float is fitted with an automatic air vent
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Linx Refresher Review
c) A float trap does not vent air better than bucket trap d) The air vent orifice is adjustable on a float trap
84. The thermal efficiency of Stirling cycle is the same as the efficiency of which of the following cycles?
a) Otto cycle b) Brayton cycle c) Carnot cycle d) Dual cycle
85. In a gas which flow into an expansion control and without doing work, this process is called:
a) Purging b) Scavenging c) Throttling d) Priming
86. The latent heat of vaporization decreases as the pressure and temperature of the liquid decreases. At the critical point, the heat of
vaporization becomes what?
a) Increased b) Zero c) Decreased d) Constant
87. A fluid flowing in a reversible adiabatic deceleration process to zero velocity will reach a state known as:
a) Isentropic expansion b) Isentropic compression c) Adiabatic irreversibility d) Isentropic Stagnation
88. The ratio of the actual velocity to the sound velocity.
a) Prandtl Number b) Isottop number c) Mach number d) Torecelli’s number
89. On the level of a molecule, the gas constant for one mole divided by the number of molecules in a mole is known as:
a) Avogadro’s Numberb) Planck Constant c) Boltzmann’s Constant d) Gravitational Constant
90. Which of the following is true for white ice?
a) A fast-cooled water b) A sub-cooled water
c) Due to dissolved air, gases and impurities d) Formed by blowing air during freezing
91. In the detection of refrigerant leak, sulphur stick burning in the presence of ammonia will release of which of the following colors of
smoke?
a) Dense White b) Dense Yellow c) Dense Orange d) Dense Red
92. What is a common cause of waterhammer in drying coils?
a) Wet steam supplied to the coil b) Too low a steam pressure onto the coil
c) Condensate has to lift after the steam trap d) The coil falling in the direction of steam flow
93. Which of the following statements is true?
a) Bimetallic steam traps are an ideal choice for rotating cylinders
b) Rotating cylinders can not suffer from steam locking
c) Strainers cannot be fitted to float traps which have a steam lock release
d) Air vents around the thermodynamic and inverted bucket traps can considerably improve start-up times
94. Name the principle cause of waterhammer?
a) Water particles suspended in steam b) Water allowed to build up in pipes
c) Water droplets carried along the insides of pipes d) Wet steam passing through steam traps
95. As a general rule, the cooling water side of the condenser should be scheduled for inspection every which of the following number of
months?
a) Month b) 3 Months c) 6 Months d) Year
96. How do you call a refrigeration system in which only part of the refrigerant passing over the heat transfer separated from the vapor and
re-circulated?
a) Absorption refrigeration system b) Cascade refrigeration system
c) Flooded refrigeration system d) Steam jet refrigeration system
97. What do you call a refrigeration system in which the refrigerant gas evolved in the evaporator is taken up in an absorber and released
in a generator upon the application of heat?
a) Absorption refrigeration system b) Cascade refrigeration system
c) Flooded refrigeration system d) Steam jet refrigeration system
98. What do you call a shut-off valve other than a valve for controlling the flow of refrigerant in a refrigeration system?
a) Fusible valve b) Stop valve c) Check valve d) Relief valve
99. What is a device, used in refrigeration system, having a predetermined temperature fusible member for the relief of pressures?
a) Fusible valve b) Stop valve c) Check valve d) Relief valve
100.Which of the following ranges of humidity ratio is used for comfort air conditioning?
a) 50 to 55 % b) 55 to 60 % c) 60 to 65 % d) 45 to 50 %
THE FOLLOWING ITEMS ARE FOR YOUR READING AND FAMILIARIZATION
101.When adding the refrigerant in a refrigeration system, it shall be charge into which of the following parts of the system?
a) High pressure side b) Low pressure side c) Low and high pressure side d) Compressor discharge line
102.Why is a boiler feed tank heated to approximately 85 oC?
a) To reduce the energy required to raise steam
b) To reduce the content of total dissolved solids in the water supplied to the boiler
c) To reduce the gas content of the water
d) To reduce the content of suspended solids in the water
103.Which of the following is the chemical formula for R – 12 or dichlorodifluoromethane?
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Linx Refresher Review
a) CHCLF2 b) CCl2F2 c) CH3Cl d) C3H8
104.Which of the following is not a desirable property of a refrigerant?
a) Low thermal conductivity b) Low freezing point c) Low condensing pressure d) Low viscosity
105.It is the process of treating air so as to control simultaneously its temperature, humidity, cleanliness and distribution to meet the
comfort requirements of the occupants of the conditioned room or space. What is this?
a) Comfort Air Conditioning b) Summer Air Conditioning
c) Industrial Air Conditioning d) Commercial Air Conditioning
106.It is the ozone-destroying power of a substance measured relative to refrigerant 11 (R-11 or CFC-11).
a) Ozone Depletion Potential (ODP) b) Hydrochlorofluorocarbon (HCFC)
c) Hydrofluorocarbon (HFC) d) Global Warming Potential (GWP)
107.What always accompanies an isentropic expansion of steam?
a) An increase in entropy b) An increase in enthalpy c) A decrease in entropy d) A decrease in enthalpy
108.What is the advantage of a pressurized deaerator over an atmospheric deaerator?
a) A boiler feed tank is no longer required b) Less over all energy will be required to produce the steam
c) It can be fitted at ground level d) It removes more oxygen
109.At which typical pressure will a pressurized deaerator supplying a shell boiler normally operate?
a) 0.2 bar g b) 1.2 bar g c) 5 bar g d) Boiler pressure
110.How is the released oxygen in a pressurized deaerator prevented from being reabsorbed by the water?
a) By an air vent b) There is sufficient water surface for the air to be absorbed
c) By steam blanket over the water d) By the incoming steam against the incoming water
111.How is the water in a pressurized deaerator heated to the required temperature?
a) By a blanket of steam above the water b) By direct steam injection into the water
c) By a spray of steam as it enters the deaerator dome d) It is not heated further but just held at a higher pressure
112.In proximate analysis, the coal analysis is consisting of moisture content, fixed carbon, ash, and which of the following?
a) Sulfur b) Hydrogen c) Nitrogen d) Volatile matter
113.A relative measure of the ability of a substance to cause an increase in the temperature of the atmosphere by absorbing solar and
earth radiation that is relative to the effect of refrigerant 11.
a) Ozone Depletion Potential (ODP) b) Hydrochlorofluorocarbon (HCFC)
c) Hydrofluorocarbon (HFC) d) Global Warming Potential (GWP)
114.A ratio calculated by dividing the cooling capacity in Btu/hr by the power input in watts and any set of rating conditions, expressed in
Btu/Watt-hr; it is also defined as the amount of heat removed from the cooled space in Btu for one Watt-hour of electricity consumed.
a) Energy Efficiency Ratio (EER) b) Ozone Depletion Potential (ODP)
c) Global Warming Potential (GWP) d) Coefficient of Performance (COP)
115.Which of the following would cause low head pressure?
a) Too much cooling water b) Insufficient refrigeration gas
c) Insufficient cooling water d) Too much cooling water and insufficient refrigeration gas
116.What do you all the locus of elevations to which water will rise in the Piezometer tube?
a) Hydraulic gradient b) Space gradient c) Elevation gradient d) Velocity gradient
117.Which of the following is true if the dry-bulb and wet-bulb temperatures in air are identical?
a) The dew point of air is reached b) The mixture is completely dry
c) Relative humidity is zero d) Temperature of air cannot be determined
118.Which of the following defines Surging?
a) A fixed mass flow rate irrespective of pressure ratio
b) Change of mass flow rate in proportion to pressure ratio
c) An unsteady, periodic and reversal of flow in the compressor
d) A reduction in lift force in the compressor
119.In a Brayton cycle or gas turbine cycle, what do you call the heat exchanger that passes exhaust heat to the compressed air, prior to
combustion?
a) Reheater b) Recuperator c) Heater d) Heat exchanger
120.Dual cycle is also called as:
a) Constant pressure regenerative cycle b) Constant volume regenerative cycle
c) Constant volume and constant pressure combustion cycle d) Constant volume combustion cycle
121.The application of the conservation of energy to open systems is known as:
a) The first corollary of the second law of thermodynamics
b) The first corollary of the first law of thermodynamics
c) The second corollary of the second law of thermodynamics
d) The second corollary of the first law of thermodynamics
122.The amount of heat added to the engine required to produce 1 kW or Hp within one hour is said to be:
a) Heat added b) Heat rate c) Power output d) Heat rejected
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Linx Refresher Review
123.In a compression-ignition engine, one of the methods to avoid detonation during compression, with its limitation on the compression
ratio, is:
a) To inject the fuel after the compression process or stroke b) To increase the cut off ratio
c) To inject the fuel before the end of compression process or stroked) To lower the compression ratio
124.It is a dimensionless number used in the study of forced convection that gives a measure of the ratio of the total heat transfer to
conductive heat transfer, and is equal to the heat-transfer coefficient times the diameter divided by the thermal conductivity. What is
this number?
a) Nusselt Number b) Reynolds Number c) Prandlt Number d) Grashof Number
125.A ratio calculated by dividing the total heating capacity by the total electric input is called as:
a) Refrigerating effect b) Energy efficiency ratio
c) Coefficient of performance d) Performance rating
126.The process whereby a material extracts one or more substances present in an atmosphere or mixture of gases or liquids;
accompanied by physical change, chemical change, or both, of the material.
a) Absorptivity b) Absorption c) Evaporation d) Dehumidifying
127.A refrigeration system in which only part of the refrigerant passes over the heat transfer surface is evaporated and the balance is
separated from the vapor and recirculated.
a. Chill water system b. Multiple system c. Flooded system d. Direct expansion system
128.A temperature that would result if the psychrometric process occurring in a dehumidifier, humidifier, or surface cooler were carried to
the saturation condition of the leaving air while maintaining the same ratio of sensible to total heat load in the process.
a) Apparatus dew point temperature b) Room dew point temperature
c) Humidifier coil temperature d) Dehumidifier coil temperature
129.Which of the following is true for the sensible heating process of air conditioning?
a) The relative humidity of the air is decreased b) The relative humidity of the air is increased
c) The wet bulb temperature does not change d) The Humidity ratio is decreased
130.What is the quantity of heat required changing the state of a substance from solid to liquid without change of temperature?
a. Calorie b. Heat of fusion c. Latent heat d. Specific heat
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