This is the Multiple Choice Questions Part 6 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 6 of the Series

⇐ MCQ in Power Plant Engineering Part 5 | ME Board Exam

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

251. How many cubic meters is 100 gallons of liquid?

A. 3.7850 m^{3 }

B. 0.1638 m^{3}

C. 0.3785 m^{3}

D. 1.638 m^{3}

Answer: **Option C
**

Explanation:

252. Steam turbine is receiving 1014 lb_{m}/h_{r} of steam, determine the horsepower output of the turbine if the work done by steam is 251 Btu/lb_{m}.

A. 100 hp

B. 462.7 hp

C. 200 hp

D. 600 hp

Answer: **Option A**

Explanation:

253. What is the resulting pressure when one pound of air at 15 psia and 200°F is heated at constant volume to 800°F?

A. 32.1 psia

B. 15 psia

C. 28.6 psia

D. 36.4 psia

Answer: **Option C**

Explanation:

254. A bicycle tire has a volume of 600 cm^{3}. It is inflated with carbon dioxide to pressure of 551.43 kPa, 20°C. How many grams of CO_{2} are contained in the tire? R_{CO2} = 0.18896 kJ/kg.K.

A. 5.98 g

B. 6.43 g

C. 4.63 g

D. 3.83 g

Answer: **Option A**

Explanation:

255. The absolute pressure at the bottom of a vertical column of water is 15.5 psia. What is the height of this column?

A. 22 in

B. 9.2 in

C. 12 in

D. 9.8 in

Answer: **Option A**

Explanation:

256. A water temperature rise of 18°F in the water cooled condenser is equivalent to what in °C?

A. 7.78°C

B. 10°C

C. 263.56 K

D. -9.44°C

Answer: **Option B**

Explanation:

257. An oil storage tank contains oil with specific gravity of 0.88 and depth of 20 meters. What is the hydrostatic pressure at the bottom of the tank in kg/cm^{2}?

A. 1.67

B. 1.76

C. 1.56

D. 1.87

Answer: **Option B**

Explanation:

258. A vertical column of water will be supported to what height by standard atmospheric pressure?

A. 34 ft.

B. 36 ft.

C. 24 ft.

D. 26 ft.

Answer: **Option A**

Explanation:

259. The specific weight of liquid is 60 lb./ft^{3}. What is the equivalent to kN/m^{3}?

A. 9.334

B. 9.249

C. 9.643

D. 9.420

Answer: **Option D**

Explanation:

260. A cylinder weighs 150 lb_{f}. Its cross-sectional area is 40 square inches. When the cylinder stands vertically on one end, what pressure does the cylinder exert on the floor?

A. 14.1 kPa

B. 58.2 kPa

C. 0.258 bar

D. 0.141 bar

Answer: **Option C**

Explanation:

261. What is the absolute pressure exerted on the surface of a submarine cruising 300 ft. below the free surface of the sea? Assume specific gravity of sea water is 1.03.

A. 133.9 psia

B. 148.6 psia

C. 100.7 psia

D. 103.7 psia

Answer: **Option B**

Explanation:

262. Air enters a nozzle steadily at 2.21 kg/m^{3} and 30 m/s. What is the mass flow rate through the nozzle if the inlet area of the nozzle is 80 cm^{2}?

A. 0.35 kg/s

B. 3.5 kg/s

C. 5.3 kg/s

D. 0.53 kg/s

Answer: **Option D**

Explanation:

263. What is the work required to accelerate an 800-kg car from rest to 100 km/h on a level road?

A. 308.6 kJ

B. 806.3 kJ

C. 608.3 kJ

D. 386 kJ

Answer: **Option A**

Explanation:

264. Assuming that there are no heat effects and no friction effects, find the speed of a 3220-lb_{m} body after it falls 778 ft. from rest.

A. 422 ft./s

B. 424 ft./s

C. 224 ft./s

D. 424 ft./s

Answer: **Option C**

Explanation:

265. What is the flow rate through a pipe 4 inches in diameter carrying water at a velocity of 11 ft./s?

A. 430.84 gpm

B. 7.18 gpm

C. 340.28 gpm

D. 39.16 gpm

Answer: **Option A**

Explanation:

266. If the specific weight of a liquid is 58.5 lb_{f} per cubic foot, what is the specific volume of the liquid in cm^{3}/g?

A. 0.5321 cm^{3}/g

B. 0.6748 cm^{3}/g

C. 0.9504 cm^{3}/g

D. 1.0675 cm^{3}/g

Answer: **Option D**

Explanation:

267. What is the resulting pressure when one pound of air at 0.3 psig and 200°F is heated at constant volume to 800°F?

A. 0.572 psig

B. 28.6 psia

C. 7.857 psia

D. 1.2 psig

Answer: **Option B**

Explanation:

268. A small pump serving as model, when tested in laboratory using water at 3600 rpm, delivered 30 cfs at a head of 125 ft. If the efficiency of this model pump is 84%, predict the horsepower input to the prototype pump if it is to develop the same head as model pump and the model pump has a scale ratio of 1:10. Assume the efficiency of the prototype pump is 90%.

A. 50.6 hp

B. 4730 hp

C. 3740 hp

D. 60.5 hp

Answer: **Option B**

Explanation:

269. Pump at is best efficiency point (BEP) has a capacity of 10,500 gpm while developing a head of 60 ft. at a rotative speed of 1450 rpm. What is the specific speed of the pump?

A. 2760

B. 1450

C. 2476

D. 6892

Answer: **Option D**

Explanation:

270. A pump will be installed below the reservoir water surface with a required net positive suction head (NPSHR) of 50 ft. The barometric pressure is 14.3 psia, and the vapor pressure is 0.5 psia. Assume friction losses in the intake piping are 5 ft. Find the maximum allowable elevation of the pump relative to the water surface intake to avoid cavitation.

A. 45 ft.

B. 55 ft.

C. 18.2 ft.

D. 23.2 ft.

Answer: **Option D**

Explanation:

271. A centrifugal pump is at best efficiency point (BEP). Assume the pump characteristic are head, h = 7 m, flow rate, Q = 19 liters/s, and rotative speed n = 1170 rpm. Find the specific speed in SI units.

A. 0.4

B. 0.71

C. 10.41

D. 3.94

Answer: **Option B**

Explanation:

272. The pressure of a confined gas at a constant temperature is tripled, what will happen to the volume?

A. The volume will be tripled

B. The volume will be reduced to one-third of its original value

C. The volume will remain unchanged

D. The volume is constant

Answer: **Option B**

Explanation:

273. A 15 in. diameter fan operates at 1600 rpm and develops a head of 6 in. of water and delivers 120 cfm. What volumetric capacity for geometrically similar fan will develop 6 in of water at 1300 rpm?

A. 147.7 cfm

B. 181.8 cfm

C. 97.5 cfm

D. 79.2cfm

Answer: **Option B**

Explanation:

274. A radial-flow pump operating at maximum efficiency at a specific speed of 2500 is to deliver 260 gpm against a head of 129 ft. at a rotative speed of 2100 rpm. Find the required number of stages (i.e., impellers).

A. 2 stages

B. 3 stages

C. 4 stages

D. 5 stages

Answer: **Option C**

Explanation:

275. How many identical turbines, operating at 139.0 rpm and 91% efficiency (specific speed = 5.4), are needed to exploit a head of 1200 ft. and a flow of 1660 ft^{3}/s?

A. 2 turbines

B. 3 turbines

C. 4 turbines

D. 5 turbines

Answer: **Option B**

Explanation:

276. How many poles should a 60-Hz generator have, if it is connected to a turbine operating under a design head of 3000 ft. with a flow of 82 cfs? Assume turbine specific speed and efficiency 3 and 84 percent respectively.

A.10-pole

B. 12-pole

C. 14-pole

D. 16-pole

Answer: **Option D**

Explanation:

277. It is proposed to build a dam in a river where the flow rate is 10 m3/s and a 32-m drop in elevation can be achieved for flow through a turbine. If a turbine is 82 percent efficient, what is the maximum power that can be achieved? Specific gravity of river is 0.998.

A. 2570 kW

B. 3133 kW

C. 3820 kW

D. 262 kW

Answer: **Option A**

Explanation:

278. What type of turbine delivers 25,000 bhp at 500 rpm under a net head of 5350 ft.?

A. Impulse turbine

B. Francis turbine

C. Kaplan turbine

D. Propeller turbine

Answer: **Option A**

Explanation:

279. A 26-hp pump delivers 475 gpm of gasoline (γ = 42.5 lb/ft^{3}) at 20 C with 78% efficiency. What pressure rise result across the pump?

A. 30.2 psi

B. 32.7 psi

C. 120.3 psi

D. 73.2 psi

Answer: **Option D**

Explanation:

280. A model pump delivering water at 180°F (γ = 60.6 lb/ft^{3}; p_{vapor} = 7.54 psia) at 900 gpm and 2500 rpm begins to cavitate when the inlet pressure and velocity are 13 psia and 22 fps. Find the required NPSH of a prototype which is 4 times larger and runs at 1100 rpm.

A. 63.5 ft.

B. 20.49 ft.

C. 6.61 ft.

D. 36 ft.

Answer: **Option A**

Explanation:

281. The diameter of the discharge pipe is 8 in. and that of the intake pipe is 10 in. The pressure gage at discharge reads 32 psi, and vacuum gage at the intake reads 12 in. Hg. If the discharge flow rate = 4.0 ft^{3}/s of water and the brake horsepower is 49.0, find the efficiency. The intake and the discharge are at the same elevation.

A. 82.2%

B. 80.9%

C. 55.8%

D. 58.46%

Answer: **Option A**

Explanation:

282. A piston positive-displacement pump (PDP) has a 6-in diameter and a 2.5-in stroke. Its crankshaft rotates at 300 rpm. Calculate its output at 94 percent volumetric efficiency.

A. 12.27 cfm

B. 13.5 cfm

C. 10 cfm

D. 11.53 cfm

Answer: **Option D**

Explanation:

283. A centrifugal pump (efficiency 88%) lifts water through a total height of 40 m from a reservoir to discharge. Pumping is through 300 m of 75 mm diameter pipe at the rate of 20 liter/s. If pipe friction, f = 0.025, what horsepower is required?

A. 28.4 kW

B. 32.2 kW

C. 25 kW

D. 9 kW

Answer: **Option B**

Explanation:

284. In order to predict the behaviour of a small oil pump, tests are to be made on a model using air. The pump is to be driven by a 1/20-hp motor at 1800 rpm and a ¼-hp motor is available to drive the air at 600 rpm. Using specific gravity of oil at 0.912 and density of air constant at 0.076 lb/ft^{3}, what size model should be built?

A. The model should be 2 times as large as the oil pump.

B. The model should be 5 times as large as the oil pump.

C. The model should be 8 times as large as the oil pump.

D. The model should be 10 times as large as the oil pump.

Answer: **Option D**

Explanation:

285. A double-overhung impulse turbine installation is to develop 20,000 hp at 275 rpm under a net head of 1100 ft. Determine the specific speed.

A. 4.34

B. 6.14

C. 203.61

D. 144

Answer: **Option A**

Explanation:

286. An impulse wheel at best produces 125 hp under a head of 210 ft. By what percent should the speed be increased for a 290-ft head?

A. 82.25%

B. 17.5%

C. 72.41%

D. 27.59%

Answer: **Option B**

Explanation:

287. What is the power ratio of a pump and its 1/5 scale model if the ratio of heads is 4 to 1?

A. 20

B. 200

C. 12.5

D. 125

Answer: **Option B**

Explanation:

288. The speed of a centrifugal pump is doubled. By what factor does the pump head change?

A. 0.125

B. 0.25

C. 4

D. 8

Answer: **Option C**

Explanation:

289. Compute the specific volume of an air-vapor mixture in cubic meter per kg of dry air when the following conditions prevail: t = 40°C, w = 0.015 kg/kg, and P_{t} = 90 kPa.

A. 0.99 m^{3}/kg

B. 0.89 m^{3}/kg

C. 0.79 m^{3}/kg

D. 0.69 m^{3}/kg

Answer: **Option A**

Explanation:

290. A coil has an inlet temperature of 70°F and outlet of 80°F. If the mean temperature of the coil is 130°F, find the bypass factor of the coil.

A. 0.28

B. 1.2

C. 0.82

D. 0.83

Answer: **Option D**

Explanation:

291. Compute the pressure drop of 35°C air flowing with a mean velocity of 5 m/s in a circular sheet-metal duct 400mm in diameter and 25 m long. Use friction factor, f = 0.04, and ρ_{air} = 1.3799 kg/m^{3}.

A. 431.22 Pa

B. 221.34 Pa

C. 312.24 Pa

D. 422.31 Pa

Answer: **Option A**

Explanation:

292. Pressure difference of 400 Pa is available to force 20°C air through a circular sheet-metal duct 450 mm in diameter and 25 m long. At 20°C, ρ = 1.204 kg/m3 and take friction factor, f = 0.016. Determine the velocity.

A. 27.34 ft/s

B. 43.72ft/s

C. 89.68 ft/s

D. 86.98 ft/s

Answer: **Option A**

Explanation:

293. A rectangular duct has a dimension of 0.25 m by 2 m. Determine the equivalent diameter of the duct.

A. 0.50 m

B. 0.60 m

C. 0.70 m

D. 0.40 m

Answer: **Option D**

Explanation:

294. To what height will a barometer column rise if the atmospheric conditions are 13.9 psia and 68°F and barometer fluid is mercury?

A. 3.56 ft.

B. 5.36 ft.

C. 2.36 ft.

D. 3.26 ft.

Answer: **Option C**

Explanation:

295. To what height will a barometer column rise if the atmospheric conditions are 13.9 psia and 68°F and barometer fluid is ethyl alcohol?

Note: @ 68°F; P_{v} =138.5 lb_{f}/ft^{3} and specific gravity of 0.79 for ethyl alcohol:

A. 79.37 in

B. 37.79 in

C. 353.54 in

D. 453.53 in

Answer: **Option D**

Explanation:

296. What is the pressure 7000 ft. below the water surface of the ocean? Neglect compressibility.

A. 512,000 psf

B. 324,500 psf

C. 447,000 psf

D. 213,000 psf

Answer: **Option C**

Explanation:

297. If atmospheric air 14.7 psia and 60°F at sea level, what is the pressure at 14212 ft. altitude if air is incompressible?

Note: @ 60°F, the density of air is 0.0763 lb_{m}/ft^{3}; P_{1} = 14.7 psia.

A. 5.4674 psia

B. 7.5304 psia

C. 7.1696 psia

D. 7.1966 psia

Answer: **Option C**

Explanation:

298. Water (ρ = 62.4 lb_{m}/ft^{3}) is flowing through a pipe. A pitot-static gage registers 3.0 inches of mercury. What is the velocity of the water in the pipe? Note: ρHg = 848.6 lb_{m}/ft_{3}.

A. 14.7 ft/s

B. 41.7 ft/s

C. 71.4 ft/s

D. 74.1 ft/s

Answer: **Option A**

Explanation:

299. The mass of an outside air at 50°C in an air conditioning unit is 60 kg. Find the temperature after mixing if the outside air mixed with 40 kg with recirculated air at 35°C.

A. 44°C

B. 39°C

C. 52°C

D. 47°C

Answer: **Option A**

Explanation:

300. A creamery must cool 20,000 liters of milk received each day from an initial temperature of 29°C to a final temperature of 2°C in 5 hours. If refrigeration losses amount to 10 percent of the cooling load, what must be the capacity of their refrigerating machine? Note: specific heat of milk is 3.9 kJ/kg-K and SG = 1.05.

A. 38.5 TOR

B. 36.5 TOR

C. 37.5 TOR

D. 39.5 TOR

Answer: **Option A**

Explanation:

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