You dont have javascript enabled! Please enable it! MCQ in Power Plant Engineering Part 10 | ME Board Exam

# MCQ in Power Plant Engineering Part 10 | ME Board Exam

This is the Multiple Choice Questions Part 10 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 10 of the Series

Choose the letter of the best answer in each questions.

451.ย  Specific volume is the number of cubic meters of mixture per kilogram of dry air. If dry air has these following properties: Ra = 287 J/kg-K, T = 303 K, Pa = 99.604 kPa. Solve for the specific volume.

A. 0.873 m3/kg

B. 0.853 m3/kg

C. 0.953 m3/kg

D. 0.783 m3/kg

Explanation:

452.ย  Aย  refrigeratingย  systemย  operatesย  on the reversed Carnot Cycle. The higher temperature of theย  refrigerantย  inย  theย  systemย  isย  120ยฐFย  andย  theย  lowerย  isย 10ยฐF.ย The capacity is 20 tons. Neglect losses. Determine the coefficient of performance.

A. 2.732

B. 5.373

C. 7.372

D. 4.273

Explanation:

453.ย  Atย  aย  pressureย  ofย  60ยฐF,ย  aย  motorbike Ire is inflated to 33 psig. As it is driven along the C -5 road,ย  theย  temperatureย  roseย  toย  76ยฐF.ย  Assumingย  theย  volumeย  remainsย  constant,ย  determineย  the final gauge pressure.

Given:

P1 = 33 psig + 14.7 psig = 47.7 psig

T1 = 60ยฐF + 460 = 520ยฐR

T2 = 76ยฐF + 460 = 536ยฐR

A. 34.47 psig

B. 49.17 psig

C. 35.00 psig

D. 34.30 psig

Explanation:

454.ย  Steam enters a turbine stage with an enthalpy of 3700 kJ/kg and a velocity of 80 m/s and leavesย  withย  anย  enthalpyย  ofย  2864ย  kJ/kgย  withย  a velocity of 12.8 m/s. If the rate of a steam flow throughย  the turbineย  is 0.44 kg/s, what is the workย  done in kW?

A. 365 kW

B. 365.64 kW

C. 366.0 kW

D. 366.50 kW

Explanation:

455.ย  Aluminumย  hasย  aย  specificย  heatย  ofย  0.902ย  J/g -ยฐC.ย  Howย  muchย  heatย  isย  lostย  whenย  aย  pieceย  of aluminumย  withย  aย  massย  ofย  23.984ย  gย  coolsย  fromย  aย  temperatureย  ofย  415.0ยฐCย  toย  aย  temperatureย  of 22.0ยฐC?

A. 8500 J

B. 6000 J

C. 80000 J

D. 7500 J

Explanation:

456.ย  Ifย  theย  temperatureย  ofย  anย  airย  parcel isย  -20.5ยฐC, and its density is 0.690 kg/m3, what is the pressure of the air parcel?

A. 40 kPa

B. 50 kPa

C. 60 kPa

D. 70 kPa

Explanation:

457.ย  A 35.0 mL sample of gas is enclosed in a flask at 22 degrees Celsius. If the flask was placed in an ice bath at 0 degrees Celsius,ย  what would the new gas volume be if the pressure is held constant?

A. 34.1 mL

B. 32.1 mL

C. 32.39 mL

D. 33.1 mL

Explanation:

458.ย  A car engine with a power output of 65 hp has a thermal efficiency of 24%. Determine the fuel consumptionย  rate of this car if the fuel has a heating value of 19,000 Btu/lb m.

A. 36.28 lbm/hr

B. 37.28 lbm/hr

C. 37.28 lbm/hr

D. 35.30 lbm/hr

Explanation:

459.ย  The thermal efficiency of a Carnot cycle operating between 170ยฐC and 620ยฐC is closest to:

A. 44%

B. 50%

C. 63%

D. 73%

Explanation:

460.ย  Compute the humidity ratio of air at 70% relative humidity and 25ยฐC when the barometric pressure is 101.325 kPa. From the steam tables: Psat @ 34 ยฐCย  = 3.169 kPa.

A. 0.014 kgwater vapor/kgdry air

B. 0.14 kgwater vapor/kgdry air

C. 1.4 kgwater vapor/kgdry air

D. 0.0014 kgwater vapor/kgdry air

Explanation:

461.ย  A pressure gauge registers 50 psig in a region where the barometer reads 14.8 psia. Find the absolute pressure in kPa.

A. 666.66 kPa

B. 556.66 kPa

C. 446.66 kPa

D. 336.66 kPa

Explanation:

462.ย  Consider 1 kg of air at 32ยฐC that expanded by a reversible polytropic process with n = 1.25 untilย  theย  pressureย  isย  halved. Determineย  the heat transfer. Specific heat at constant volume for air is 0.1786 kJ/kg-K.

A. 17.02 kJ heat rejected

B. 7.05 kJ heat rejected

Explanation:

463.ย  A Carnot cycle uses nitrogen (k = 1.399) as the working substance. The heat supplied is 54 kJ and the adiabaticย  expansion ratio is 10. Determine the heat rejected.

A. 10 kJ

B. 32.4 kJ

C. 21.6 kJ

D. 54 kJ

Explanation:

464.ย  Aย  tankย  containsย  20ย  kgย  ofย  airย  atย  200 kPa (gage) and 23ยฐC. During the heating process the temperatureย  ofย  airย  rises.ย  Forย  safetyย  purposesย  aย  technicianย  installed a relief -type valve so that pressure of air inside the tank never exceeds 260 kPa (gage). At what air temperature the relief valve will start releasing air?

A. 112ยฐC

B. 92ยฐC

C. 82ยฐC

D. 102ยฐC

Explanation:

465.ย  An air compressor takes in 9 kg/min of air at 98 kPa; ฯ1 = 0.125 m3/kg and discharges it at 680 kPa; ฯ2 = 0.03 m3/kg. The increase of internal energy is 93 kJ/kg and the work done on air is 163ย  kJ/kg;ย  theย  changeย  inย  potentialย  andย  kineticย  energyย  areย  neglected.ย  Howย  muchย  heatย  is transferred per kg of air?

A. 264.15 kJ/kg

B. 61.85 kJ/kg

C. 288.65 kJ/kg

D. 78.15 kJ/kg

Explanation:

466.ย  During a reversible process, there are abstracted 317 kJ/s from 1.134 kg/s of a certain gas while the temperature remains constant at 26.7ยฐC. For this gas cp = 2.232 and cv = 1.713 kJ/kg-K. The initial pressure is 586 kPa. Determine the final volume flow rate.

A. 0.301 m3/s

B. 0.03 m3/s

C. 0.5 m3/s

D. 0.05 m3/s

Explanation:

467.ย  Flowย  ofย  waterย  inย  aย  pipeย  hasย  aย  velocityย  atย  10ย  metersย  perย  second.ย  Determineย  theย  velocity head of the water.

A. 50.1 meters

B. 5.10 meters

C. 8.20 meters

D. 100 meters

Explanation:

468.ย  Aย  Dieselย  cycleย  hasย  aย  cut-offย  ratioย  ofย  2.20ย  andย  aย  compressionย  ratioย  ofย  10.ย  Findย  theย  cycle efficiency.

A. 55.10%

B. 59.735%

C. 52.23%

D. 62.37%

Explanation:

469.ย  Aย  dieselย  cycleย  hasย  anย  initialย  temperatureย  ofย  27ยฐC.ย  Ifย  theย  cut-offย  ratioย  isย  2.50ย  and compression ratio is 12,ย  find the maximum cycle temperature.

A. 1634.4ยฐC

B. 1753.44ยฐC

C. 2010.3ยฐC

D. 1983.4ยฐC

Explanation:

470. A diesel cycle, which takes in air at 1 bar and 26ยฐC, has a compression ratio of 19. Calculate the operating clearance in percent.

A. 8.08

B. 8.56

C. 7.52

D. 5.55

Explanation:

471.ย  Anย  Ottoย  cycleย  hasย  anย  initialย  pressureย  ofย  100 kPaย  andย  hasย  aย  pressureย  ofย  400 kPaย  after adiabatic compression. Find the cycle efficiency.

A. 32.70%

B. 34.70%

C. 36.70%

D. 38.70%

Explanation:

472.ย  An Otto cycle has a clearance of 8%ย  and heat added of 1000 kJ. Find the heat rejected.

A. 564 kJ

B. 353 kJ

C. 709 kJ

D. 867 kJ

Explanation:

473. Anย  Otto cycle has a heat rejected of 300 kJ and work of 700 kJ. Find the cycle efficiency.

A. 56%

B. 60%

C. 70%

D. 50%

Explanation:

474.ย  An Otto cycle has a pressure ratio of 7. What is the cycle compression ratio?

A. 5.18

B. 6.34

C. 7.34

D. 4.01

Explanation:

475. Find the power of a rotating shaft which develops a torque of 188 N-m at 1350 rpm.

A. 101.54 hp

B. 53.63 hp

C. 63.35 hp

D. 35.63 hp

Explanation:

476.ย  Determineย  theย  pressureย  exertedย  onย  aย  diverย  atย  30 mย  belowย  theย  freeย  surfaceย  ofย  theย  sea. Assume a barometric pressure of 101 kPa and the specific gravity of sea water is 1.03.

A. 404 kPa

B. 410 kPa

C. 420 kPa

D. 430 kPa

Explanation:

477.ย  An air compressor has an inlet enthalpy of 35 Btu/lb and an exit enthalpy of 70 Btu/lb. The massย  flowย  rateย  ofย  airย  isย  3ย  lb/s.ย  Ifย  theย  heatย  lossย  isย  466.62ย  Btu/min,ย  findย  theย  workย  input to the compressor.

A. 139.59 hp

B. 149.59 hp

C. 159.59 hp

D. 169.59 hp

Explanation:

478.ย  An automobile tire is inflated to 35 psig at 54ยฐF. Afterย  being driven, the temperature rises to 80ยฐF. Determine the final gage pressure assuming that the tire is inflexible.

A. 36.51 psig

B. 37.51 psig

C. 38.51 psig

D. 39.51 psig

Explanation:

479.ย  Aย  condenserย  vacuumย  gaugeย  readsย  600ย  mm Hgย  whenย  theย  barometerย  readsย  760ย  mm Hg. What is the absolute condenser pressure in bar?

A. 0.0213

B. 0.061

C. 0.213

D. 0.610

Explanation:

480.ย  Water flows in a pipe at the rate of 10 kg/s. If the velocity of flow is 10 m/s, find the pipe diameter.

A. 30.23 mm

B. 35.68 mm

C. 38.39 mm

D. 42.39 mm

Explanation:

481.ย  What is the resulting pressure when one kilogram of air at 104 kPa and 98ยฐC is heated at constant volume to 450ยฐC?

A. 202.67 kPa

B. 194.67 kPa

C. 186.53 kPa

D. 198.65 kPa

Explanation:

482.ย  Determine the degrees of superheat of steam at 101.325 kPa and 170ยฐC.

A. 50ยฐC

B. 70ยฐC

C. 60ยฐC

D. 80ยฐC

Explanation:

483.ย  Calculate the approximate enthalpy of water at 90ยฐC.

A. 366.83 kJ/kg

B. 376.83 kJ/kg

C. 386.83 kJ/kg

D. 396.83 kJ/kg

Explanation:

484.ย  A Carnot cycle operates between 30ยฐC and 350ยฐC. Find the cycle efficiency.

A. 51.36%

B. 63.45%

C. 45.37%

D. 76.45%

Explanation:

485.ย  A Carnot cycle has a maximum temperature of 550ยฐF and minimum temperature of 100ยฐF. If the heat added is 4200 Btu/min, find the horsepowerย  outputย  of the engine.

A. 34.53

B. 40.56

C. 44.13

D. 65.40

Explanation:

486.ย  Aย  Carnotย  cycleย  hasย  aย  sinkย  temperatureย  ofย  100ยฐFย  andย  aย  cycleย  efficiencyย  ofย  70%.ย  Findย  the temperatureย  of the heat source.

A. 1306.70ยฐF

B. 1406.70ยฐF

C. 1506.70ยฐF

D. 1606.70ยฐF

Explanation:

487.ย  The quality of steam is 20%. This means that:

A. mass of liquid is 20%, mass of vapor is 80%

B. mass of liquid is 20%, mass of vapor is 0%

C. mass of liquid is 80%, mass of vapor is 20%

D. none of these

Explanation:

488.ย  Fiftyย  kilogramsย  ofย  coolingย  waterย  perย  secondย  enterย  theย  condenserย  atย  25ยฐCย  andย  leavesย  at 50ยฐC.ย  Find the heat carried away by water.

A. 1234.45 kW

B. 5233.75 kW

C. 2340.53 kW

D. 3140.25 kW

Explanation:

489.ย  Tenย  kilogramsย  perย  secondย  ofย  steam enter the turbine with an enthalpy of 3200 kJ/kg and enter the condenser with an enthalpy of 2500 kJ/kg in a Rankine cycle. If the turbine efficiency is 80% and the generator efficiency is 90%, determine the powerย  plant output.

A. 4320 kW

B. 3213 kW

C. 4056 kW

D. 5040 kW

Explanation:

490.ย  Determine the quality of steam in a vessel containing 2 kg of saturated vapor and 8 kg of saturated liquid.

A. 100%

B. 20%

C. 80%

D. 60%

Explanation:

491.ย  The condenser of a reheat power plant rejects heat at the rate of 600 kW. The mass flow rateย  ofย  coolingย  waterย  isย  5ย  kg/sย  andย  theย  inletย  cooling water temperature is 35ยฐC. Calculate the condenser cooling water exit temperature.

A. 43.45ยฐC

B. 53.45ยฐC

C. 63.66ยฐC

D. 74.34ยฐC

Explanation:

492.ย  A heat engine has a thermal efficiency of 50%. How much power does the engine produce when heat is transferred at a rate of 109 kJ/hr?

A. 50 MW

B. 75 MW

C. 139 MW

D. 147 MW

Explanation:

493.ย  Oneย  kilogramย  ofย  airย  isย  compressedย  adiabaticallyย  andย  inย  aย  steady-flowย  manner.ย  The compression efficiency is 80% and the work done on the air is 265 kJ/kg. Compute the heat.

A. 212 kJ/kg

B. 100 kJ/kg

C. 0 kJ/kg

D. 331.25 kJ/kg

Explanation:

494.ย  Three-hundredย  kilojoulesย  ofย  heatย  flowย  byย  conductionย  fromย  theย  outsideย  toย  theย  insideย  ofย  a coldย  storage in one hour. If the temperature and all other conditions are the same, what is the heat flowing through the cold storage room in two hours?

A. 600 kJ

B. 900 kJ

C. 300 kJ

D. 1,200 kJ

Explanation:

495.ย  Determine the density of air at 760 mmHg absolute and 22ยฐC?

A. 1.014 kg/m3

B. 1.316 kg/m3

C. 1.197 kg/m3

D. 1.266 kg/m3

Explanation:

496.ย  A refrigerating machine that isย  classified as a one-ton machine has the capacityย  to produce a cooling effect of?

A. 3.516 kW

B. 12,000 Btu/hr

C. 211 kJ/min

D. All of these

Explanation:

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