Energy Engineering MCQs
Energy Engineering MCQs
These Energy Engineering multiple-choice questions and their answers will help you strengthen your grip on the subject of Energy Engineering. You can prepare for an upcoming exam or job interview with these 80+ Energy Engineering MCQs.
So scroll down and start answering.
1: A stone that weighs 70 kg in air, weighs 120 kg when immersed in water. What is the specific weight of the stone?
A. 2200 kg/m3
B. 2400 kg/m3
C. 2620 kg/m3
D. 2840 kg/m3
The work ratio of a gas turbine plant working on a Joule cycle is 45%. If it produces 5000 kW of power, what is the power consumed by the compressor?
A.
4512.8 kW
B.
5081.3 kW
C.
6111.11 kW
D.
8304.5 kW
3: If the work produced by a Carnot engine operating between 350 °C and 30 °C is 400 kJ, then find the entropy change during heat addition.
A. 0.8
B. 1.03
C. 1.25
D. 1.67
4: What will be the discharge over a 5-meter long suppressed rectangular weir with head over crest = 0.4 m?
A. 2.3 m3/s
B. 1.98 m3/s
C. 2-5 m3/s
D. 3.1 m3/s
5: A laminated wall of surface area 1.5 m2, is made up of 0.3 m of refractory bricks (k = 2 kcal-m/hr m2 °C), 0.3 m of insulation (k =0.15 kcal-m/hr m7- °C)and 0.45 m of brick (k = 1.5 kcal-m/hr m7- °C). If the inner and outer temperature of the wall is 1030°C and 30°C. respectively. what is the rate of heat transfer?
A. 546.65 kcal/hr
B. 587.32 kcal/hr
C. 612.24 kcal/hr
D. 643.16 kcal/hr
6: A MOSFET operates in which of the following modes when VGSGS(TH)?
A. hmic mode
B. Saturation mode
C. Active mode
D. Cut-off mode
7: Which of the following expressions calculates the overland flow time (To in hours) for any basin? Where, L0 = distance of critical point and H = difference in elevation.
A. a)
B. b)
C. C)
D. d)
A.
a)
B.
b)
C.
C)
D.
d)
9: Which of the following cycles works as a reverse of Bell-Coleman air refrigeration cycle?
A. Ericsson cycle
B. Brayton cycle
C. Otto cycle
D. Rankine cycle
10: What is the order of the mass flow ratio of Freon-12 in comparison to NH3 if the temperature limits and refrigeration load are the same?
A. 1:5
B. 5:1
C. 1:9
D. 9:1
11: The presence of which of the following gases is tested by doing the lead acetate test?
A. CO
B. C02
C. CH 4
D. H2S
A.
a)
B.
b)
C.
c)
D.
d)
13: Composition of landfill gases is primarily:
A. co and N02
B. co2 and N02
C. so2 and co
D. CH4 and co2
To calculate the velocity of flow in a circular sewer of diameter 'D' (running full) using Chezy's formula {V=C «/ (rs)], what should be the value of hydraulic mean radius (where. r= hydraulic mean depth of flow and S: hydraulic gradient)?
A. D/2
B. D/4
C. D/6
D. D/8
Given,
n = rugosity coefficient,
r = hydraulic depth and.
s = bed slope of sewer
The formula ("V=1/n r288”) for determining the velocity of flow in m/s was evolved by which of the following?
A.
Kuichling
B.
Fruhling
C.
Chezy
D.
Manning
The settlement velocity of the particles is calculated using Hazin‘s formula,
VS = 418(GS-Gw)d[3T+7O/100 ] (where symbols have their usual meaning). when the particle diameter is:
A.
less than 0.02 mm
B.
greater than 0.01 mm
C.
less than 0.1 mm
D.
more than 0.1 mm
17: Find the ratio of the temperature drop across two layers of a composite wall of a furnace, where the two layers have equal thickness and the ratio of thermal conductivities is 4:5.
A. ⅓
B. 114
C. 3/4
D. 5/4
18: Twenty-five percent of the absorbed heat from the source is rejected by an engine working on Carnot cycle. If the sink temperature is maintained at 30°C, calculate the value of source temperature.
A. 800°C
B. 695°C
C. 1485°C
D. 1032°C
19: Find the effective head under which a Francis turbine operates. It works at 450 rpm, has a unit speed of 60 rpm and develops a power of 550 kW.
A. 104 m
B. 83.7 m
C. 62.5 m
D. 51.9 m
A.
a)
B.
b)
C.
c)
D.
d)
A.
a)
B.
b)
C.
C)
D.
d)
Forty percent of the heat supplied is rejected by a reversible heat engine during a cycle of operation.
What will be the COP if this engine is reversed and used as a heat pump?
A.
1.8
B.
2.3
C.
2.5
D.
2.9
The ratio between the high and the low working temperatures of a refrigerator based on reversed Carnot Cycle is 0.6. If a heat pump is operated between this same temperature range.
what will be the COP of the heat pump?
A.
5
B.
4.3
C.
3.6
D.
2.5
24: 1200 kl of heat is transferred from a constant temperature system at 700 K to another at 500K (environmental temperature = 300 K). Calculate the loss of available energy associated with this transfer.
A. 360 kJ
B. 396.6 kJ
C. 458.7 kJ
D. 480 kJ
A.
A
B.
B
C.
C
D.
D
What is the expression for the maximum blade efficiency of a Parson's turbine? Where, a = jet angle at the entrance.
A. Cos2a/(1- Cos2a)
B. (2 Cos2a)/( 1+ Cos2a)
C. Cosu/2
D. C0520
27: What will be the cycle efficiency for the maximum work capacity in a gas turbine operating on Brayton cycle? It is given that the Brayton cycle has maximum temperature of 1250 K and minimum temperature of 350K.
A. 35%
B. 43%
C. 47%
D. 51%
28: What is the range of typical density in kg/cm (in-situ) of well-compacted municipal solid waste in a landfill?
A. 150 to 320
B. 310 to 500
C. 600 to 770
D. 850 to 1200
29: Determine the value of the COP of a vapour compression refrigeration system. Given, enthalpy at beginning of compression = 80 kJ/kg. enthalpy at the end of compression = 180 kJ/kg and enthalpy at the end of condensation = 230 kJ/kg.
A. 1.2
B. 1.5
C. 2.3
D. 3.6
A.
a)
B.
b)
C.
C)
D.
d)
31: I Find the blade-speed ratio for maximum diaphragm efficiency in a simple impulse turbine. It is given that the nozzle angle at the entrance is 35°.
A. 0.41
B. 0.56
C. 0.62
D. 0.83
32: For a circular sewer (with diameter d) and a square section sewer (of side a) to be hydraulically equivalent. which of the following needs to be true?
A. nD8/3 ___ 4a8/3
B. 1-D5/3 = 4a5/3
C. nD8/3 : 4a5/3
D. nD3/5 = 4a8/3
A.
a)
B.
b)
C.
c)
D.
d)
34: What is ratio of the lower to the higher absolute temperatures for a Carnot refrigerator that has a COP = 7?
A. ⅗
B. 5/9
C. ⅞
D. 4/7
Fill in the blank.
The value of B for a power BJT with IC =18 A. la = 2.2 A and 'cs =14 mA is .
A.
7.63
B.
8.12
C.
8.73
D.
9.34
36: If 0 = maximum flood discharge, C = Ryves coefficient and A = catchment area then Q is equal to:
A. CA ⅓
B. CA ⅕
C. CA ⅔
D. CA 2/5
37: What will be the value of relative humidity when wet bulb depression is zero?
A. 0
B. 30%
C. 80%
D. 100%
38: Assuming the energy released by coal as 92OX107 kJ/h, calculate the rate at which heat is rejected from a thermal electric power plant, which produces 1200 MW of power.
A. 530.2 MW
B. 780.9 MW
C. 1100.3 MW
D. 1355.5 MW
39: In a stainless fin (thermal conductivity = 0.18 W/cm°C)of a constant cross-sectional area of 2.5 cm2 and length 1 cm exposed to ambient temperature of 50°C (with a surface heat transfer co-efficient of 0.003W/cm2°C). the temperature distribution is given by (T - T...) = 3x2 - 5x + 6. where T is in °C and x is in cm. Find heat dissipated by the fin surface for a base temperature 120°C.
A. 3.67 w
B. 4.28 w
C. 4.83 w
D. 5.14 w
40: 300 KJ/s of heat is supplied to a heat engine at a constant fixed temperature of 230°C. If heat is rejected at 30°C then assuming the cycle as reversible, calculate the amount of heat rejected.
A. 180.71 KJ/s
B. 203.4 KJ/s
C. 229.5 KJ/s
D. 253.5 KJ/s
41: A sharp edged vertical orifice issues a jet of water under a constant head of 0.55 m. The horizontal and vertical co-ordinates measured from the vena-contracta. at a certain point of issuing jet. are 0.512m and 0.09m, respectively. Assuming Cd = 0.7, find the value of CC.
A. 0.48
B. 0.53
C. 0.6
D. 0.71
A.
a)
B.
b)
C.
c)
D.
d)
43: Calculate the degree of reaction in a reaction turbine, if the enthalpy drop in a stage is 70 units and the enthalpy drop in the moving blades is 40 units.
A. 0.57
B. 0.73
C. 0.92
D. 1.06
44: The cycle direction of a Carnot engine (with an efficiency of 60%) is reversed. what is the COP of reversed Carnot cycle?
A. 0.53
B. 0.66
C. 0.82
D. 0.97
45: A gas turbine is supplied with gas at 1200 K and 10 bar to expand adiabatically to 2 bar. Find the power developed in kW/kg of gas per second and the exhaust gas temperature. Mean specific heat at constant pressure is 1.0425 kJ/kgK and mean specific heat at constant volume is 0.7662 kJ/kgK.
A. 876 kW/kg and 984 K. respectively
B. 672 kW/kg and 732 K. respectively
C. 434 kW/kg and 784 K, respectively
D. 381 kW/kg and 539 K. respectively
A.
a)
B.
b)
C.
C)
D.
d)
A.
a)
B.
b)
C.
C)
D.
d)
48: A 250 mm pipe line has a pitot-static tube paced in its centre, with one orifice pointing upstream and the other perpendicular to it. Assuming the pressure difference between the two orifices to be 50 mm of water when discharge through the pipe is 1500 L/min and the mean velocity in the pipe to be 0.83 of the central velocity, find the coefficient of the pitot tube.
A. 0.62
B. 0.67
C. 0.78
D. 0.83
Given below is the information regarding a steam power plant.
Power developed by the turbine = 1300 kW
Heat supplied to the boiler = 3400 kJ/kg
Heat rejected by the system to cooling water = 2500 kJ/kg
Teed pump work required to condensate back into the boiler = 7kW
What will be the mass flow rate through the cycle?
A.
0.85 kg/s
B.
1.4 kg/s
C.
2.9 kg/s
D.
3.6 kg/s
50: From which of the following chemical compounds is the odour of drying paint or varnish is derived?
A. Ethylene
B. Ethene
C. Methane
D. Benzene
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