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

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

**Choose the letter of the best answer in each questions.**

101.ย Aย rectangularย foundationย cross -sectionย hasย aย bedย plateย dimensionย ofย 8ย ftย xย 10ย ft.ย The uniform clearance on each side is 1 ft. The height of the foundation is 4.5 ft. If the weight of the steelย barย reinforcementsย neededย isย ยฝ%ย ofย weightย ofย foundation,ย findย t heย weightย ofย theย steel bars. Use concrete density of 2400 kg/m^{3}.

A. 173.47 kg

B. 183.47 kg

C. 163.47 kg

D. 153.47 kg

Answer: **Option B
**

Explanation:

102.ย Aย steamย pipeย havingย aย surfaceย temperatureย ofย 250ยฐCย passesย throughย aย roomย whereย the temperatureย isย 27ยฐC.ย Theย outsideย diameterย of the pipe isย ย 100 mm and emissivity factor isย ย 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

Answer: **Option C**

Explanation:

103. Brine enters a circulating brine cooler at the rate of 60 m^{3}/hr atย -8ยฐC and leaves atย -18ยฐC. Specificย heatย ofย brineย isย 1.072ย kJ/kg -Kย andย aย specificย gravityย ofย 1.12.ย Determineย theย tonsย of refrigeration.

A. 53.5 TR

B. 65.3 TR

C. 33.5 TR

D. 56.9 TR

Answer: **Option D**

Explanation:

104.ย A turbo-charged, 16 cylinder, Vee-type diesel engine has an air consumption of 3,000 kg/hr perย cylinderย atย ratedย loadย andย speed.ย Thisย airย isย drawnย inย throughย aย filterย byย aย centrifugal compressor directly connected to the exhaust gas turbine. The temperature of the air from theย compressor is 135ยฐCย and a counter flow air cooler reduces the air temperature to 45 ยฐC before it goesย toย theย engineย suctionย header.ย Coolingย waterย entersย theย airย coolerย at 30ยฐC and leaves at 40ยฐC. Calculate the log mean temperature difference.

A. 47.23ยฐC

B. 87.82ยฐC

C. 43.34ยฐC

D. 65.24ยฐC

Answer: **Option C**

Explanation:

105. Water is flowing in a pipe with radius of 30 cm at a velocity of 5ย ย m/s at the temperature in the pipe.ย 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

Answer: **Option A**

Explanation:

106.ย Computeย theย amountย ofย condensateย formedย duringย aย 10ย minuteย warm-upย ofย 180ย meter pipeย conveysย theย saturatedย steamย withย enthalpyย ofย vaporization,ย hfg =ย 1947.8ย kJ/kg.ย The minimumย externalย temperatureย ofย pipeย isย 2ยฐC.ย Theย finalย temperatureย ofย pipeย isย 195ยฐC.ย The specific heat of pipe material is 0.6 kJ/kg -ยฐC. The specific weight is 28 kg/m.

A. 240.69 kg

B. 982.45 kg

C. 299.64 kg

D. 423.45 kg

Answer: **Option C**

Explanation:

107. The discharge pressure of an air compressor is 5 times the suction pressure. If volume flow atย suctionย isย 0.1ย m^{3}/s,ย whatย isย the suctionย pressureย ย ifย compressorย workย isย ย 19.57 kWย (use n = 1.35).

A. 97 kPa

B. 98 kPa

C. 99 kPa

D. 100 kPa

Answer: **Option B**

Explanation:

108.ย Theย initial condition of air in an air compressor is 98 kPa and 27ย ยฐC and dischargesย 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 m^{3}/hr

B. 551.62 m^{3}/hr

C. 561.62 m^{3}/hr

D. 571.62 m^{3}/hr

Answer: **Option D**

Explanation:

109.ย An air compressor has a suction volume of 0.35 m^{3}/sย ย at 97 kPa and discharges at 650 kPa. How much powerย 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

Answer: **Option D**

Explanation:

110. A two stage air intercooler has an intercooler pressure of 4 kg/cm^{2}. What is the discharge pressure if suction pressure is 1 kg/cm^{2}?

A. 3 kg/cm^{2}

B. 9 kg/cm^{2}

C. 12 kg/cm^{2}

D. 16 kg/cm^{2}

Answer: **Option D**

Explanation:

111.ย Aย two-stage air compressor at 100 kPa and 22ยฐC discharges to 750 kPa. If the intercooler intake isย 105ยฐC, determine the value of n.

A. 1.400

B. 1.326

C. 1.345

D. 1.288

Answer: **Option B**

Explanation:

112.ย Aย singleย actingย compressorย hasย aย volumetricย efficiencyย ofย 89%,ย operatesย atย 500ย rpm.ย It takesย inย airย atย 100ย kPaย andย 30ยฐCย andย dischargesย itย atย 600ย kPa.ย Theย airย handledย isย 8ย m^{3}/min measuredย atย dischargedย condition.ย Ifย compressionย isย isentropic,ย findย theย effectiveย mean pressure in kPa.

A. 233.34

B. 973.17

C. 198.34

D. 204.82

Answer: **Option A**

Explanation:

113.ย Aย water-jacketedย air compressor handles 0.343 m^{3}/s of air entering at 96.5 kPa and 21ยฐC andย leavingย atย 480ย kPaย andย 132ยฐC;ย 10.9ย kg/hrย ofย coolingย waterย entersย theย jacketย at 15ยฐC and leaves at 21ยฐC. Determine the compressor brake power.

A. 23.163 kW

B. 62.65 kW

C. 34.44 kW

D. 19.33 kW

Answer: **Option B**

Explanation:

114.ย A double suction centrifugal pump delivers 20 ft^{3}/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

Answer: **Option C**

Explanation:

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

A. 6

B. 4

C. 5

D. 7

Answer: **Option C**

Explanation:

116.ย Theย suctionย pressureย ofย aย pumpย readsย 3ย in.ย ofย mercuryย vacuumย andย dischargeย pressure readsย 140ย psiย isย usedย toย deliverย 120ย gpmย ofย waterย withย specificย volumeย ofย 0.0163ย ft^{3}/lb. Determine the pump work.

A. 4.6 kW

B. 5.7 kW

C. 7.4 kW

D. 8.4 kW

Answer: **Option C**

Explanation:

117.ย Aย submersibleย pumpย deliversย 350ย gpmย ofย waterย toย aย heightย of 5 ft from the ground. The pumpย whereย installedย 150ย ftย belowย theย groundย levelย andย aย drawdownย ofย 8ย ft.ย duringย the operation.ย 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

Answer: **Option D**

Explanation:

118.ย A vacuum pump is used to drain a flooded mine shaft of 20ยฐC water.ย 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

Answer: **Option A**

Explanation:

119.ย A submersible, multi-stage, centrifugal deep well pump 260 gpm capacity is installed in a wellย 27ย ftย belowย theย staticย waterย 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 storageย tank.ย Totalย dischargeย headย developedย byย pump,ย includingย frictionย inย pipingย isย 243ย ft. Calculateย theย diameterย ofย theย impel lerย ofย thisย pumpย inย inchesย ifย eachย impellerย diameter developed a head of 38 ft.

A. 3.28

B. 5.33

C. 3.71

D. 6.34

Answer: **Option C**

Explanation:

120.ย Aย fanย draws 1.42 m^{3} per second of air at a static pressure of 2.54 cm of water through a ductย 300ย mmย diameterย andย dischargesย itย throughย aย ductย ofย 275ย mmย diameter.ย Determine the static fan efficiency if total fan is 75% and air is measured at 25ยฐC and 760 mm Hg.

A. 50.11%

B. 53.69%

C. 65.67%

D. 45.34%

Answer: **Option B**

Explanation:

121.ย A water cooler uses 50 lb/hr of melting ice to cool running water from 80ยฐF to 42ยฐF. Based on the inside coil area, U_{i} = 110 Btu/hr-ft^{2} -ยฐF. Find the gpm of water cooled.

A. 0.10 GPM

B. 0.21 GPM

C. 0.38 GPM

D. 0.45 GPM

Answer: **Option C**

Explanation:

122.ย The charge in a Diesel engine consists ofย 18.34 grams of fuel, with lower heating value of 42,571ย kJ/kg,ย andย 409ย gramsย ofย fuelย andย productsย ofย combustion.ย Atย theย beginningย of compression, T1 = 60ยฐC. Let rkย = 14. For constant cp = 1.11 kJ/kg-ยฐC, what should be the cut-off ratio in the correspondingย ย ideal cycle?

A. 2.05

B. 2.34

C. 5.34

D. 2.97

Answer: **Option D**

Explanation:

123. The gain of entropy during isothermal nonflow process of 5 lb of air at 60ยฐF is 0.462 Btu/ยฐR. Find the V_{1}/V_{2}.

A. 3.85

B. 0.259

C. 1.0

D. 0.296

Answer: **Option B**

Explanation:

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

Answer: **Option A**

Explanation:

125. In a Brayton cycle that operates between temperature limits of 300 K and 1773 K with k = 1.4,ย determineย theย temperatureย atย theย endย ofย compressionย (isentropic)ย forย maximumย workย of the cycle.

A. 780 K

B. 690.5 K

C. 730 K

D. 350 K

Answer: **Option C**

Explanation:

126.ย Aย 35%ย solutionย leavesย theย absorberย andย 30%ย solutionย entersย theย absorber.ย Theย heat removedย from the absorber by cooling wate r is 547.6 Btu and ammonia is superheated by 10ยฐ. Find the poundย per poundย of ammonia gas from the evaporating coils.

A. 11

B. 12

C. 13

D. 14

Answer: **Option C**

Explanation:

127.ย Aย Carnotย refrigerationย systemย operatesย atย T_{max}/T_{min}ย =ย 1.5.ย Findย theย kWย perย tonย of refrigeration.

A. 1.91

B. 2.15

C. 1.76

D. 1.55

Answer: **Option C**

Explanation:

128.ย Assume 8 ft^{3} of air at 100 psi and 100ยฐF are compressed isothermally to a volume of 2 ft^{3}. 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

Answer: **Option A**

Explanation:

129. Predict the pressure of nitrogen gas at T = 200 K andย ฯ
ย = 0.00385 L/g and b = 0.00141 L/g; a = 0.178 L^{2}-kPa/g^{2}. Useย Van der Waals equation.

A. 15,331 kPa

B. 14,331 kPa

C. 13,331 kPa

D. 12,331 kPa

Answer: **Option D**

Explanation:

130. A Francis turbine is to be operated at a speed of 600 rpmย and with discharge of 4 m^{3}/s. If r_{1} = 0.6 m,ย ฮฒ = 110ยฐ, and the blade height B is 10 cm, what should be the guide vane angleย ฮฑ_{1} for non-separating flow conditionย at the runnerย entrance?

A. 14.4ยฐ

B. 15.4ยฐ

C. 16.4ยฐ

D. 17.4ยฐ

Answer: **Option D**

Explanation:

131.ย 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 1.15ย kg/m^{3}?

A. 6.85 m/s

B. 3.45 m/s

C. 4.39 m/s

D. 9.28 m/s

Answer: **Option D**

Explanation:

132.ย A fan delivers 5.7 m^{3}/sย ย 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 m^{3}/sย ย 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

Answer: **Option A**

Explanation:

133.ย Aย rigidย containerย isย closedย atย oneย endย andย measuresย 8ย inย diameterย byย 12ย inย long.ย The containerย isย heldย verticalย 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

Answer: **Option C**

Explanation:

134.ย Anย empty,ย openย canย isย 30ย cmย highย withย aย 15ย cmย diameter.ย Theย can,ย withย theย openย end down,ย isย pushedย underย waterย withย aย densityย ofย 1000ย kg/m^{3}.ย Findย theย waterย levelย inย theย 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

Answer: **Option B**

Explanation:

135.ย A cylindrical pipe with water flowing downward at 0.03 m^{3}/s having top diameter of 0.08, bottomย diameter of 0.04 m and height of 1.5 m. Find the pressureย insideย the pipe.

A. 154.63 kPa

B. 197.93 kPa

C. 252.44 kPa

D. 243.92 kPa

Answer: **Option C**

Explanation:

136.ย Determineย theย sizeย ofย pipeย whichย willย deliverย 8ย litersย ofย mediumย oil ( ฮฝย = 6.10 x 10^{-6} m^{2}/s) assuming laminar flow conditions.

A. 622 mm

B. 754 mm

C. 950 mm

D. 835 mm

Answer: **Option D**

Explanation:

137.ย The type of flow occupying in a 1 cm diameter pipe which water flows at a velocity of 2.50 m/s. Use ฮฝ = 1.13 x 10^{-6} m^{2}/s for water.

A. turbulent

B. constant

C. laminar

D. none of these

Answer: **Option A**

Explanation:

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

Answer: **Option A**

Explanation:

139.ย 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 betweenย points 1 and 2.

A. 4.29 m

B. 2.59 m

C. 6.32 m

D. 1.87 m

Answer: **Option D**

Explanation:

140.ย Waterย flowingย atย theย rateย ofย 10ย m/sย fromย anย orificeย atย bottomย ofย aย reservoir.ย Findย the pressure at the bottomย of reservoir.

A. 30 kPa

B. 40 kPa

C. 50 kPa

D. 60 kPa

Answer: **Option C**

Explanation:

141.ย Steamย flowsย through a nozzle at 400ยฐC and 1ย MPaย (h = 3263.9 kJ/kg) with velocity of 300 m/s. Findย the stagnation enthalpy.

A. 3300 kJ/kg

B. 3290 kJ/kg

C. 3320 kJ/kg

D. 3309 kJ/kg

Answer: **Option D**

Explanation:

142.ย Airย flowsย throughย aย nozzleย atย a speed of 350 m/s. Find the stagnation temperature if the entrance temperatureย is 200ยฐC.

A. 241.25ยฐC

B. 251.25ยฐC

C. 261.25ยฐC

D. 271.25ยฐC

Answer: **Option C**

Explanation:

143.ย Carbonย dioxideย flowsย throughย aย nozzleย withย aย speedย ofย 400ย m/s.ย Computeย theย dynamic temperature.

A. 92.56 K

B. 94.56 K

C. 96.56 K

D. 98.56 K

Answer: **Option B**

Explanation:

144.ย Carbonย dioxideย flowsย throughย aย nozzleย withย speed of 380 m/s. The entrance condition of nozzle is 250ยฐC 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

Answer: **Option A**

Explanation:

145.ย Airย entersย aย diffuserย withย aย velocityย ofย 200ย m/s.ย Determineย theย velocityย ofย soundย ifย air temperatureย is 30ยฐC.

A. 349 m/s

B. 359 m/s

C. 369 m/s

D. 379 m/s

Answer: **Option A**

Explanation:

146.ย Airย flowsย through a nozzle with temperature of entrance of 420 K stagnationย temperature of 468 K. Find the Mach number.

A. 0.744

B. 0.754

C. 0.764

D. 0.774

Answer: **Option B**

Explanation:

147.ย 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

Answer: **Option D**

Explanation:

148.ย Anย insulatedย rigidย tankย initiallyย containsย 1.5ย lbย ofย heliumย atย 80ยฐFย andย 50ย psia.ย Aย paddle wheel with power rating of 0.02 hp is operated within the tank for 30 min. Determine the final temperature.

A. 159.22ยฐF

B. 169.22ยฐF

C. 179.22ยฐF

D. 189.22ยฐF

Answer: **Option C**

Explanation:

149.ย Aย 4 m^{2} asphalt pavement with emissivity of 0.85 has a surface temperature of 50ยฐC. Find the maximumย 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

Answer: **Option D**

Explanation:

150.ย Air at 10ยฐC 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 m^{2}.ย 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

Answer: **Option D**

Explanation:

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