This is the Multiple Choice Questions Part 1 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

#### Start Practice Exam Test Questions Part 1 of the Series

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

1. Find the work possess for a helium gas at 20°C.

A. 609 kJ/kg

B. 168 kJ/kg

C. 229 kJ/kg

D. 339 kJ/kg

Answer: **Option A**

Explanation:

2. Two kilogram of gas is confined in a 1 m^{3} tank at 200 kPa and 88°C. What type of gas is in the tank?

A. Helium

B. Ethane

C. Methane

D. Ethene

Answer: **Option B**

Explanation:

3. Find the enthalpy of Helium if its internal energy is 200 kJ/kg.

A. 144 kJ/kg

B. 223.42 kJ/kg

C. 333.42 kJ/kg

D. 168 kJ/kg

Answer: **Option C**

Explanation:

4. Compute the mass of a 2 m3 propane at 280 kPa and 40°C.

A. 6.47 kg

B. 5.1 kg

C. 10.20 kg

D. 9.47 kg

Answer: **Option D**

Explanation:

5. Compute the air flow in ft^{3}/min of mechanical ventilation required to exhaust an accumulation of refrigerant due to leaks of the system capable of revolving air from the machinery for a mass of 4 lbs. refrigerant.

A. 200

B. 210

C. 220

D. 230

Answer: **Option A**

Explanation:

6. Compute the free aperture cross section in m^{3} for the ventilation of a machinery room if the mass of refrigerant is 9 kg.

A. 0.314

B. 0.414

C. 0.514

D. 0.614

Answer: **Option B**

Explanation:

7. A 29.53” x 39.37” pressure vessel contains ammonia with f = 0.041. Compute the minimum required discharge capacity of the relief device in kg/hr.

A. 106.71 kg/hr.

B. 108.71 kg/hr.

C. 110.71 kg/hr.

D. 112.71 kg/hr.

Answer: **Option C**

Explanation:

8. Compute the maximum length of the discharge pipe installed on an outlet of a pressure-relief device in feet for internal pipe diameter of 0.5 inch and rated discharge capacity is 8 lb/min of

air. The rated pressure of relief valve is 10 psig.

A. 0.286 ft.

B. 0.386 ft.

C. 0.486 ft.

D. 0.586 ft.

Answer: **Option A**

Explanation:

9. A thermal power plant has the heat rate of 11,363 Btu/kW-hr. Find the thermal efficiency of the plant.

A. 28%

B. 30%

C. 34%

D. 40%

Answer: **Option B**

Explanation:

10. What is the hydraulic gradient of a 1 mile, 17 inches inside diameter pipe when 3300 gal/min of water flow with f = 0.03?

A. 0.00714

B. 0.00614

C. 0.00234

D. 0.00187

Answer: **Option A**

Explanation:

11. Find the loss of head in the pipe entrance if speed of flow is 10 m/s.

A. 5.10 m

B. 10.2 m

C. 17.4 m

D. 2.55 m

Answer: **Option D**

Explanation:

12. Wet material, containing 220% moisture (dry basis), is to be dried at a rate of 1.5 kg/s in a continuous dryer to give a product containing 10% (dry basis). Find the moisture removed in

kg/hr.

A. 3543.75 kg/hr.

B. 3513.75 kg/hr.

C. 3563.75 kg/hr.

D. 3593.75 kg/hr.

Answer: **Option A**

Explanation:

13. Copra enters a dryer containing 70% moisture and leaves 7% moisture. Find the moisture removed on each pound of solid in the final product.

A. 6.258 lbs.

B. 1.258 lbs.

C. 4.258 lbs.

D. 2.258 lbs.

Answer: **Option D**

Explanation:

14. A 1 m x 1.5 m cylindrical tank is full of oil with SG = 0.92. Find the force acting at the bottom of the tank in dynes.

A. 106.33 x 10^{3} dynes

B. 106.33 x 10^{4} dynes

C. 106.33 x 10^{5} dynes

D. 106.33 x 10^{6} dynes

Answer: **Option D**

Explanation:

15. Find the pressure at the 100 fathom depth of water in kPa.

A. 1,793.96 kPa

B. 1,893.96 kPa

C. 1,993.96 kPa

D. 1,693.96 kPa

Answer: **Option A**

Explanation:

16. Find the depth in furlong of the ocean (SG = 1.03) if the pressure at the sea bed is 2,032.56 kPa.

A. 1

B. 2

C. 3

D. 4

Answer: **Option A**

Explanation:

17. Find the mass of 10 quartz of water.

A. 10.46 kg

B. 9.46 kg

C. 11.46 kg

D. 8.46 kg

Answer: **Option B**

Explanation:

18. Find the mass of carbon dioxide having a pressure of 20 psia at 200°F with 10 ft^{3} volume.

A. 1.04 lbs.

B. 1.14 lbs.

C. 1.24 lbs.

D. 1.34 lbs.

Answer: **Option C**

Explanation:

19. Find the heat needed to raise the temperature of water from 30°C to 100°C with 60% quality. Consider an atmospheric pressure of 101.325 kPa. Use the approximate enthalpy formula of liquid.

A. 293.09 kJ/kg

B. 1,772.90 kJ/kg

C. 1,547.90 kJ/kg

D. 1,647.29 kJ/kg

Answer: **Option D**

Explanation:

20. Find the enthalpy of water at 212°F and 14.7 psi if the dryness factor is 30%. Use the approximate enthalpy formula of liquid.

A. 461 Btu/lb.

B. 471 Btu/lb.

C. 481 Btu/lb.

D. 491 Btu/lb.

Answer: **Option B**

Explanation:

21. An air compressor consumed 1200 kW-hr per day of energy. The electric motor driving the compressor has an efficiency of 80%. If indicated power of compressor is 34 kW, find the mechanical efficiency of the compressor.

A. 117.65%

B. 75%

C. 85%

D. 90%

Answer: **Option C**

Explanation:

22. A refrigeration system consumed 28,800 kW-hr per month of energy. There is 20% of energy lost due to the cooling system of the compressor and the motor efficiency is 90%. If the COP of the system is 6, find the mechanical efficiency of the compressor.

A. 43.15 TR

B. 46.15 TR

C. 49.15 TR

D. 41.15 TR

Answer: **Option C**

Explanation:

23. A 23 ton refrigeration system has a heat rejected of 100 kW. Find the energy efficiency ratio of the system.

A. 13.42

B. 14.42

C. 15.42

D. 16.42

Answer: **Option B**

Explanation:

24. A 200 mm x 250 mm, 8-cylinder, 4-stroke diesel engine has a brake power of 150 kW. The mechanical efficiency is 80%. If two of the cylinders were accidentally cut off, what will be the new friction power?

A. 31.50 kW

B. 33.50 kW

C. 35.50 kW

D. 37.50 kW

Answer: **Option D**

Explanation:

25. If the energy efficiency ratio of the refrigeration system is 12.6, what is the COP of the system?

A. 3.69

B. 4.23

C. 5.92

D. 6.83

Answer: **Option A**

Explanation:

26. An air compressor has a power of 40 kW at 4% clearance. If the clearance will increase to 7%, what is the new power?

A. 70 kW

B. 40 kW

C. 53 kW

D. 60 kW

Answer: **Option B**

Explanation:

27. What is the approximate value of temperature of water having enthalpy of 208 Btu/lb.?

A. 138.67°C

B. 115.55°C

C. 258.67°C

D. 68.67°C

Answer: **Option B**

Explanation:

28. Convert 750°R to K.

A. 390.33 K

B. 395.33 K

C. 410.33 K

D. 416.33 K

Answer: **Option D**

Explanation:

29. An Otto cycle has a compression ratio of 8. Find the pressure during compression.

A. 18.38

B. 16.38

C. 14.38

D. 12.28

Answer: **Option A**

Explanation:

30. A diesel cycle has a cut off ratio of 2.5 and expansion ratio of 4. Find the clearance of the cycle.

A. 9.11%

B. 5.55%

C. 11.11%

D. 15.15%

Answer: **Option C**

Explanation:

31. A dual cycle has an initial temperature of 30°C. The compression ratio is 6 and the heat addition at constant volume process is 600 kJ/kg. If the cut-off ratio is 2.5, find the maximum temperature of the cycle.

A. 3638.50°C

B. 3365.50°C

C. 3565.50°C

D. 3965.50°C

Answer: **Option B**

Explanation:

32. A 3-stage air compressor compresses air from 100 kPa to 1000 kPa. Find the intercooler pressure between the 1st and 2nd stage.

A. 505.44 kPa

B. 108.44 kPa

C. 316.23 kPa

D. 215.44 kPa

Answer: **Option D**

Explanation:

33. A 10-stage air compressor compresses air from 100 kPa to 800 kPa. Find the intercooler pressure between the 1st and 2nd stage.

A. 282.84 kPa

B. 113.21 kPa

C. 123.11 kPa

D. 333.51 kPa

Answer: **Option C**

Explanation:

34. A 3-stage air compressor compresses air from 100 kPa to 700 kPa. Find the intercooler pressure between the 2nd and 3rd stage.

A. 365.88 kPa

B. 375.88 kPa

C. 385.88 kPa

D. 395.88 kPa

Answer: **Option A**

Explanation:

35. Carnot cycle A, B and C are connected in series so that the heat rejected from A will be the heat added to B. and heat rejected from B will be added to C. Each cycle operates between 30°C and 400°C. If heat added to A is 1000 kW, find the work output of C.

A. 111.44 kW

B. 549.78 kW

C. 247.53 kW

D. 141.89 kW

Answer: **Option A**

Explanation:

36. Air compressed adiabatically from 30°C to 100°C. If the mass of air being compressed is 5 kg, find the change of entropy.

A. 1.039 kJ/K

B. 0.746 kJ/K

C. 0

D. 1.245 kJ/K

Answer: **Option C**

Explanation:

37. Two kilogram of air in a rigid tank changes its temperature from 32°C to 150°C. Find the work done during the process.

A. 236

B. 170

C. 195

D. 0

Answer: **Option D**

Explanation:

38. Determine the atmospheric pressure at a location where barometric reading is 740 mm Hg and gravitational acceleration is g = 9.7 m/s^{2}. Assume the temperature of mercury to be 10°C, at which the density is 13,570 kg/m^{3}.

A. 99.45 kPa

B. 97.41 kPa

C. 95.44 kPa

D. 98.66 kPa

Answer: **Option B**

Explanation:

39. The barometer of a mountain hiker reads 930 mbars at the beginning of a hiking trip and 780 mbars at the end. Neglecting the effect of altitude on local gravitational acceleration, determine the vertical distance climbed. Assume g = 9.7 m/s^{2}.

A. 1274.21 m

B. 1289.00 m

C. 1267.34 m

D. 1583.34 m

Answer: **Option B**

Explanation:

40. The lower half of a 10 m high cylindrical container is filled with water and the upper half with oil that has SG = 0.85. Determine the pressure difference between the top and bottom if

the cylinder.

A. 90.74 kPa

B. 92.74 kPa

C. 83.38 kPa

D. 98.10 kPa

Answer: **Option A**

Explanation:

41. An ideal gas at 0.80 atmospheres and 87°C occupies 0.450 liter. How many moles are in the sample? (R = 0.0821 liter-atm/mole-K).

A. 0.0002 mole

B. 0.0378 mole

C. 0.0122 mole

D. 0.0091 mole

Answer: **Option C**

Explanation:

42. A certain gas at 101.325 kPa and 10°C whose volume is 2.83 m^{3} capacity. Before admission, the storage vessel contained gas at a pressure and temperature of 137.8 kPa and 26°C; after admission, the pressure increased to 1171.8 kPa. What should be the final temperature of the gas in the vessel in Kelvin?

A. 298.0

B. 319.8

C. 180.0

D. 314.2

Answer: **Option D**

Explanation:

43. A perfect gas has a value of R = 58.8 ft-lb/lb.-°R and k = 1.26. If 20 Btu are added to 10 lbs. of this gas at constant volume when initial temperature is 90°F, find the final temperature.

A. 97°F

B. 104°F

C. 154°F

D. 185°F

Answer: **Option A**

Explanation:

44. Ammonia weighing 22 kg is confirmed inside a cylinder equipped with a piston has an initial pressure of 413 kPa at 38°C. If 3200 kJ of heat is added to the ammonia until its final pressure and temperature is 413 kPa and 100°C, respectively. What is the amount of work done by the fluid in kJ?

A. 667

B. 304

C. 420

D. 502

Answer: **Option A**

Explanation:

45. A tank contains 90 ft^{3} of air at a pressure of 350 psig; if the air is cooled until its pressure and temperature decreases at 200 psig and 70°F respectively, what is the decrease in internal energy?

A. 6232.09 Btu

B. -5552 Btu

C. 5552 Btu

D. -6232.09 Btu

Answer: **Option D**

Explanation:

46. A large mining company was provided with a 3 m^{3} of compressed air tank. Air pressure in the tank drops from 700 kPa to 150 kPa while the temperature remains constant at 28°C. What percentage has the mass of air in the tank been reduced?

A. 74.09

B. 72.45

C. 76.56

D. 78.57

Answer: **Option D**

Explanation:

47. A 4 m^{3}/hr. pump delivers water to a pressure tank. At the start, the gage read 138 kPa until it reads 276 kPa and then the pump was shut off. The volume of the tank is 180 liters. At 276 kPa, the water occupied 2/3 of the tank volume. Determine the volume of the water that can be taken out until the gage reads 138 kPa.

A. 31.20 liters

B. 34.59 liters

C. 16.87 liters

D. 29.50 liters

Answer: **Option B**

Explanation:

48. A refrigeration plant is rated at 15 tons capacity. How many pounds of air per hour will it cool from 70°F to 90°F at constant temperature?

A. 50,000 lb./hr.

B. 37,500 lb./hr.

C. 52,000 lb./hr.

D. 45,000 lb./hr.

Answer: **Option B**

Explanation:

49. An air standard engine has a compression ratio of 18 and a cut-off ratio of 4. If the intake air pressure and temperature are 100 kPa and 27°C, find the work in kJ per kg.

A. 2976

B. 2166

C. 1582

D. 2751

Answer: **Option C**

Explanation:

50. Determine the air-standard efficiency of an engine operating on the diesel cycle with a clearance of 6% when the suction pressure is 99.7 kPa and the fuel is injected for 7% of the stroke. Assume k = 1.4.

A. 62.11%

B. 51.20%

C. 73.58%

D. 60.02%

Answer: **Option A**

Explanation:

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