MCQ in Power Plant Engineering Part 3 | ME Board Exam

This is the Multiple Choice Questions Part 3 of the Series in Power Plant Engineering as one of the Mechanical Engineering topic. In Preparation for the ME Board Exam make sure to expose yourself and familiarize in each and every questions compiled here taken from various sources including but not limited to past Board Exam Questions in Mechanical Engineering field, Mechanical Engineering Books, Journals and other ME References. I assume you are looking for a reviewer that will help you achieve your goal to become a License Mechanical Engineer very soon. Yes, you are in the right place to make your dream come true. Make sure to familiarize each and every questions to increase the chance of passing the Mechanical Board Examination.

MCQ Topic Outline included in ME Board Exam Syllabi

• MCQ in Power Plant Elements
• MCQ in Power Plant Design
• MCQ in Industrial Plant Engineering
• MCQ in Industrial Plant Design
• MCQ in Refrigeration Engineering and its Applications
• MCQ in Air Conditioning

Continue Practice Exam Test Questions Part 3 of the Series

⇐ MCQ in Power Plant Engineering Part 2 | ME Board Exam

Choose the letter of the best answer in each questions.

101.  A  rectangular  foundation  cross -section  has  a  bed  plate  dimension  of  8  ft  x  10  ft.  The uniform clearance on each side is 1 ft. The height of the foundation is 4.5 ft. If the weight of the steel  bar  reinforcements  needed  is  ½%  of  weight  of  foundation,  find  t he  weight  of  the  steel bars. Use concrete density of 2400 kg/m³.

A. 173.47 kg

B. 183.47 kg

C. 163.47 kg

D. 153.47 kg

102.  A  steam  pipe  having  a  surface  temperature  of  250°C  passes  through  a  room  where  the temperature  is  27°C.  The  outside  diameter  of the pipe is   100 mm and emissivity factor is   0.8. Calculate the radiated heat loss for 3 m pipe length.

A. 1434.47 W

B. 3746.35 W

C. 2851.82 W

D. 3546.45 W

103. Brine enters a circulating brine cooler at the rate of 60 m³/hr at  -8°C and leaves at  -18°C. Specific  heat  of  brine  is  1.072  kJ/kg -K  and  a  specific  gravity  of  1.12.  Determine  the  tons  of refrigeration.

A. 53.5 TR

B. 65.3 TR

C. 33.5 TR

D. 56.9 TR

104.  A turbo-charged, 16 cylinder, Vee-type diesel engine has an air consumption of 3,000 kg/hr per  cylinder  at  rated  load  and  speed.  This  air  is  drawn  in  through  a  filter  by  a  centrifugal compressor directly connected to the exhaust gas turbine. The temperature of the air from the compressor is 135°C  and a counter flow air cooler reduces the air temperature to 45 °C before it goes  to  the  engine  suction  header.  Cooling  water  enters  the  air  cooler  at 30°C and leaves at 40°C. Calculate the log mean temperature difference.

A. 47.23°C

B. 87.82°C

C. 43.34°C

D. 65.24°C

105. Water is flowing in a pipe with radius of 30 cm at a velocity of 5   m/s at the temperature in the pipe.  The density and viscosity of the water are as follows: density = 997.9 kg/s viscosity = 1.131 Pa-s. What is the Reynolds number for this situation?

A. 2647

B. 96.2

C. 3100

D. 1140

106.  Compute  the  amount  of  condensate  formed  during  a  10  minute  warm-up  of  180  meter pipe  conveys  the  saturated  steam  with  enthalpy  of  vaporization,  hfg =  1947.8  kJ/kg.  The minimum  external  temperature  of  pipe  is  2°C.  The  final  temperature  of  pipe  is  195°C.  The specific heat of pipe material is 0.6 kJ/kg -°C. The specific weight is 28 kg/m.

A. 240.69 kg

B. 982.45 kg

C. 299.64 kg

D. 423.45 kg

107. The discharge pressure of an air compressor is 5 times the suction pressure. If volume flow at  suction  is  0.1  m³/s,  what  is  the suction  pressure   if  compressor  work  is   19.57 kW  (use n = 1.35).

A. 97 kPa

B. 98 kPa

C. 99 kPa

D. 100 kPa

108.  The  initial condition of air in an air compressor is 98 kPa and 27  °C and discharges  air at 450 kPa. The bore and stroke are 355 mm and 381 mm, respectively with percent clearance of 8% running at 300 rpm. Find the volume of air at suction.

A. 541.62 m³/hr

B. 551.62 m³/hr

C. 561.62 m³/hr

D. 571.62 m³/hr

109.  An air compressor has a suction volume of 0.35 m³/s   at 97 kPa and discharges at 650 kPa. How much power  is saved by the compressor if there are two stages?

A. 18.27 kW

B. 16.54 kW

C. 13.86 kW

D. 11.58 kW

110. A two stage air intercooler has an intercooler pressure of 4 kg/cm². What is the discharge pressure if suction pressure is 1 kg/cm²?

A. 3 kg/cm²

B. 9 kg/cm²

C. 12 kg/cm²

D. 16 kg/cm²

111.  A  two-stage air compressor at 100 kPa and 22°C discharges to 750 kPa. If the intercooler intake is  105°C, determine the value of n.

A. 1.400

B. 1.326

C. 1.345

D. 1.288

112.  A  single  acting  compressor  has  a  volumetric  efficiency  of  89%,  operates  at  500  rpm.  It takes  in  air  at  100  kPa  and  30°C  and  discharges  it  at  600  kPa.  The  air  handled  is  8  m³/min measured  at  discharged  condition.  If  compression  is  isentropic,  find  the  effective  mean pressure in kPa.

A. 233.34

B. 973.17

C. 198.34

D. 204.82

113.  A  water-jacketed  air compressor handles 0.343 m³/s of air entering at 96.5 kPa and 21°C and  leaving  at  480  kPa  and  132°C;  10.9  kg/hr  of  cooling  water  enters  the  jacket  at 15°C and leaves at 21°C. Determine the compressor brake power.

A. 23.163 kW

B. 62.65 kW

C. 34.44 kW

D. 19.33 kW

114.  A double suction centrifugal pump delivers 20 ft³/s of water at a head of 12 m and running at 650 rpm. What is the specific speed of the pump?

A. 5014.12 rpm

B. 6453.12 rpm

C. 2770.73 rpm

D. 9968.73 rpm

115.  Determine the number of stages needed for a centrifugal pump if it is used to deliver 400 gal/min of water and  pump  power of 15 hp. Each impeller develops a head of 30 ft.

A. 6

B. 4

C. 5

D. 7

116.  The  suction  pressure  of  a  pump  reads  3  in.  of  mercury  vacuum  and  discharge  pressure reads  140  psi  is  used  to  deliver  120  gpm  of  water  with  specific  volume  of  0.0163  ft³/lb. Determine the pump work.

A. 4.6 kW

B. 5.7 kW

C. 7.4 kW

D. 8.4 kW

117.  A  submersible  pump  delivers  350  gpm  of  water  to  a  height  of 5 ft from the ground. The pump  where  installed  150  ft  below  the  ground  level  and  a  drawdown  of  8  ft.  during  the operation.  If water level is 25 ft above the pump, determine the pump power.

A. 7.13 kW

B. 4.86 kW

C. 7.24 kW

D. 9.27 kW

118.  A vacuum pump is used to drain a flooded mine shaft of 20°C water.  The pump pressure of water at this temperature is 2.34 kPa. The pump is incapable of lifting the water higher than 16 m. What is the atmospheric pressure?

A. 159.30

B. 132.33

C. 196.22

D. 171.9

119.  A submersible, multi-stage, centrifugal deep well pump 260 gpm capacity is installed in a well  27  ft  below  the  static  water  level and running at 300 0 rpm. Drawdown when pumping at rated capacity is 10 feet. The pump delivers the water into a 25,000 gallons capacity overhead storage  tank.  Total  discharge  head  developed  by  pump,  including  friction  in  piping  is  243  ft. Calculate  the  diameter  of  the  impel ler  of  this  pump  in  inches  if  each  impeller  diameter developed a head of 38 ft.

A. 3.28

B. 5.33

C. 3.71

D. 6.34

120.  A  fan  draws 1.42 m³ per second of air at a static pressure of 2.54 cm of water through a duct  300  mm  diameter  and  discharges  it  through  a  duct  of  275  mm  diameter.  Determine the static fan efficiency if total fan is 75% and air is measured at 25°C and 760 mm Hg.

A. 50.11%

B. 53.69%

C. 65.67%

D. 45.34%

121.  A water cooler uses 50 lb/hr of melting ice to cool running water from 80°F to 42°F. Based on the inside coil area, U_i = 110 Btu/hr-ft² -°F. Find the gpm of water cooled.

A. 0.10 GPM

B. 0.21 GPM

C. 0.38 GPM

D. 0.45 GPM

122.  The charge in a Diesel engine consists of  18.34 grams of fuel, with lower heating value of 42,571  kJ/kg,  and  409  grams  of  fuel  and  products  of  combustion.  At  the  beginning  of compression, T1 = 60°C. Let rk  = 14. For constant cp = 1.11 kJ/kg-°C, what should be the cut-off ratio in the corresponding   ideal cycle?

A. 2.05

B. 2.34

C. 5.34

D. 2.97

123. The gain of entropy during isothermal nonflow process of 5 lb of air at 60°F is 0.462 Btu/°R. Find the V₁/V₂.

A. 3.85

B. 0.259

C. 1.0

D. 0.296

124.  An auditorium seating 1500 people is to be maintained at 80°F dry bulb and 60°F wet bulb temperature when outdoor air is at 91°F dry bulb and 75°F wet bulb. Solar heat load is 110,000 Btu/hr and supply air is at 60°F, determine the amount  of supply air.

A. 93,229.17 lb/hr

B. 83,229.17 lb/hr

C. 73,229.17 lb/hr

D. 63,229.17 lb/hr

125. In a Brayton cycle that operates between temperature limits of 300 K and 1773 K with k = 1.4,  determine  the  temperature  at  the  end  of  compression  (isentropic)  for  maximum  work  of the cycle.

A. 780 K

B. 690.5 K

C. 730 K

D. 350 K

126.  A  35%  solution  leaves  the  absorber  and  30%  solution  enters  the  absorber.  The  heat removed  from the absorber by cooling wate r is 547.6 Btu and ammonia is superheated by 10°. Find the pound  per pound  of ammonia gas from the evaporating coils.

A. 11

B. 12

C. 13

D. 14

127.  A  Carnot  refrigeration  system  operates  at  T_max/T_min  =  1.5.  Find  the  kW  per  ton  of refrigeration.

A. 1.91

B. 2.15

C. 1.76

D. 1.55

128.  Assume 8 ft³ of air at 100 psi and 100°F are compressed isothermally to a volume of 2 ft³. For each end state of the process, find the bulk modulus.

A. 400 and 100 psi

B. 400 and 110 psi

C. 400 and 120 psi

D. 400 and 130 psi

129. Predict the pressure of nitrogen gas at T = 200 K and  υ  = 0.00385 L/g and b = 0.00141 L/g; a = 0.178 L²-kPa/g². Use  Van der Waals equation.

A. 15,331 kPa

B. 14,331 kPa

C. 13,331 kPa

D. 12,331 kPa

130. A Francis turbine is to be operated at a speed of 600 rpm  and with discharge of 4 m³/s. If r₁ = 0.6 m,  β = 110°, and the blade height B is 10 cm, what should be the guide vane angle  α₁ for non-separating flow condition  at the runner  entrance?

A. 14.4°

B. 15.4°

C. 16.4°

D. 17.4°

131.  The total head of fan is 187 m and has a static pressure of 210 mm of water gage, what is the velocity of air flowing if the density of air is 1.15  kg/m³?

A. 6.85 m/s

B. 3.45 m/s

C. 4.39 m/s

D. 9.28 m/s

132.  A fan delivers 5.7 m³/s   at a static pressure of 5.08 cm of water when operating at a speed of 400 rpm. The power input required is 2.963 kW. If 7.05 m³/s   are desired in the same fan and installation, find the pressure in cm of water.

A. 7.77

B. 17.14

C. 11.43

D. 5.08

133.  A  rigid  container  is  closed  at  one  end  and  measures  8  in  diameter  by  12  in  long.  The container  is  held  vertical  and is slowly moved downward until the pressure in the container is 17 psia. What will be the depth of the top of the container from the free water surface?

A. 42.36 in

B. 59.29 in

C. 63.69 in

D. 69.82 in

134.  An  empty,  open  can  is  30  cm  high  with  a  15  cm  diameter.  The  can,  with  the  open  end down,  is  pushed  under  water  with  a  density  of  1000  kg/m³.  Find  the  water  level  in  the  can when the top of the can is 50 cm below the surface.

A. 17.20 cm

B. 2.12 cm

C. 4.20 cm

D. 5.87 cm

135.  A cylindrical pipe with water flowing downward at 0.03 m³/s having top diameter of 0.08, bottom  diameter of 0.04 m and height of 1.5 m. Find the pressure  inside  the pipe.

A. 154.63 kPa

B. 197.93 kPa

C. 252.44 kPa

D. 243.92 kPa

136.  Determine  the  size  of  pipe  which  will  deliver  8  liters  of  medium  oil ( ν  = 6.10 x 10^-6 m²/s) assuming laminar flow conditions.

A. 622 mm

B. 754 mm

C. 950 mm

D. 835 mm

137.  The type of flow occupying in a 1 cm diameter pipe which water flows at a velocity of 2.50 m/s. Use ν = 1.13 x 10^-6 m²/s for water.

A. turbulent

B. constant

C. laminar

D. none of these

138. What force is exerted by a water jet, 60 mm in diameter, if it strikes a wall at the rate of 15 m/s?

A. 636.17 N

B. 442.62 N

C. 764.23 N

D. 563.34 N

139.  A 300 mm diameter pipe discharges water at a rate of 200 li/s. Point 1 on the pipe has a pressure of 260 kPa and 3.4 m below point 1 is point 2 with a pressure of 300 kPa. Compute the head loss between  points 1 and 2.

A. 4.29 m

B. 2.59 m

C. 6.32 m

D. 1.87 m

140.  Water  flowing  at  the  rate  of  10  m/s  from  an  orifice  at  bottom  of  a  reservoir.  Find  the pressure at the bottom  of reservoir.

A. 30 kPa

B. 40 kPa

C. 50 kPa

D. 60 kPa

141.  Steam  flows  through a nozzle at 400°C and 1  MPa  (h = 3263.9 kJ/kg) with velocity of 300 m/s. Find  the stagnation enthalpy.

A. 3300 kJ/kg

B. 3290 kJ/kg

C. 3320 kJ/kg

D. 3309 kJ/kg

142.  Air  flows  through  a  nozzle  at  a speed of 350 m/s. Find the stagnation temperature if the entrance temperature  is 200°C.

A. 241.25°C

B. 251.25°C

C. 261.25°C

D. 271.25°C

143.  Carbon  dioxide  flows  through  a  nozzle  with  a  speed  of  400  m/s.  Compute  the  dynamic temperature.

A. 92.56 K

B. 94.56 K

C. 96.56 K

D. 98.56 K

144.  Carbon  dioxide  flows  through  a  nozzle  with  speed of 380 m/s. The entrance condition of nozzle is 250°C and 1200 kPa. Find the stagnation pressure.

A. 2,136.34 kPa

B. 2,146.34 kPa

C. 2,156.34 kPa

D. 2,166.34 kPa

145.  Air  enters  a  diffuser  with  a  velocity  of  200  m/s.  Determine  the  velocity  of  sound  if  air temperature  is 30°C.

A. 349 m/s

B. 359 m/s

C. 369 m/s

D. 379 m/s

146.  Air  flows  through a nozzle with temperature of entrance of 420 K stagnation  temperature of 468 K. Find the Mach number.

A. 0.744

B. 0.754

C. 0.764

D. 0.774

147.  Air at 300 K and 200 kPa is heated at constant pressure to 600 K. Determine the change of internal energy.

A. 245.58 kJ/kg

B. 235.58 kJ/kg

C. 225.58 kJ/kg

D. 215.58 kJ/kg

148.  An  insulated  rigid  tank  initially  contains  1.5  lb  of  helium  at  80°F  and  50  psia.  A  paddle wheel with power rating of 0.02 hp is operated within the tank for 30 min. Determine the final temperature.

A. 159.22°F

B. 169.22°F

C. 179.22°F

D. 189.22°F

149.  A  4 m² asphalt pavement with emissivity of 0.85 has a surface temperature of 50°C. Find the maximum  rate of radiation that can be emitted from the surface.

A. 2,068 .32 watts

B. 2,078.32 watts

C. 2,088.32 watts

D. 2,098.32 watts

150.  Air at 10°C and 80 kPa enters a diffuser of a jet engine steadily with a velocity of 200 m/s. The inlet area of diffuser is 0.40 m².  Determine the mass flow rate of air.

A. 72.79 kg/s

B. 74.79 kg/s

C. 76.79 kg/s

D. 78.79 kg/s