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Steam Boilers, Engines, Nozzles & Turbines 1000+ MCQ with answer for RRB NTPC

Thursday 9th of March 2023

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1. In water tube boilers
A. Water passes through the tubes which are surrounded by flames and hot gases
B. The flames and hot gases pass through the tubes which are surrounded by water
C. Forced circulation takes place
D. None of these
Answer : A
2. A condenser in a steam power plant
A. Increases expansion ratio of steam
B. Reduces back pressure of steam
C. Reduces temperature of exhaust steam
D. All of these
Answer : D
3. Which of the following statement is correct?
A. Lancashire boiler is a fire tube boiler.
B. Fire tube boilers are internally fired.
C. Babcock and Wilcox boiler is a water tube boiler.
D. All of the above
Answer : D
4. The diameter of cylindrical shell of the Lancashire boiler is of the order of
A. 1 to 1.25m
B. 1 to 1.75 m
C. 2 to 4 m
D. 1.75 to 2.75 m.
Answer : D
5. The maximum efficiency of a De-Laval turbine is (where ? = Nozzle angle)
A. sin²?
B. cos²?
C. tan²?
D. cot²?
Answer : B
6. Which of the following statement is correct?
A. The efficiency of steam turbines is greater than steam engines
B. A flywheel is a must for steam turbine
C. The turbine blades do not change the direction of steam issuing from the nozzle
D. The pressure of steam, in reaction turbines, is increased in fixed blades as well as in moving blades
Answer : A
7. The shell diameter and length of locomotive boiler are
A. 1.5 m, 4 m
B. 1.5 m, 6 m
C. 1 m, 4 m
D. 2 m, 4 m
Answer : A
8. In a velocity compounded impulse turbine, when steam flows through the second row of moving blades,
A. Velocity increases
B. Velocity decreases
C. Velocity remains constant
D. Pressure remains constant
Answer : B
9. The ratio of heat utilised to produce steam and the heat liberated in furnace is known as
A. Boiler effectiveness
B. Boiler evaporative capacity
C. Factor of evaporation
D. Boiler efficiency
Answer : D
10. Evaporative capacity of boiler is expressed as
A. kg of steam produced
B. Steam pressure produced
C. kg of fuel fired
D. kg of steam produced per kg of fuel fifed
Answer : D
11. The diameter of internal flue tubes of a Lancashire boiler is about _________ that of its shell.
A. One-fourth
B. One-third
C. Two-fifth
D. One-half
Answer : C
12. Calorific value of coal is of the order of
A. 200-400 kcal/ kg
B. 800-1200 kcal/ kg
C. 2000-4000 kcal/ kg
D. 5000-8000 kcal/ kg
Answer : C
13. The efficiency of the plant __________ with the mechanical draught.
A. Increases
B. Decreases
C. Remains constant
D. None of these
Answer : A
14. Which of the following statement indicates the difference between Cornish boiler and Lancashire boiler?
A. Cornish boiler is a water tube boiler whereas Lancashire boiler is a fire tube boiler
B. Cornish boiler is a fire tube boiler whereas Lancashire boiler is a water tube boiler
C. Cornish boiler has one flue tube whereas Lancashire boiler has two flue tubes
D. Cornish boiler has two flue tubes whereas Lancashire boiler has one flue tube
Answer : C
15. The safety valve at superheater as compared to drum safety valve setting is set at
A. Higher value
B. Lower value
C. Same value
D. Any value
Answer : B
16. The basic job of feed water treatment in boilers is to overcome the problem of
A. Corrosion
B. Scale
C. Carryover
D. All of the above
Answer : D
17. A valve installed between the boiler and the feed pump is
A. Blow off cock
B. Feed check valve
C. Steam stop valve
D. None of these
Answer : B
18. Fire tube boilers are limited to a maximum design working pressure of
A. 1 kg/cm
B. 6 kg/cm
C. 17 kg/cm²
D. 100 kg/cm²
Answer : C
19. The basic purpose of drum in boiler is to
A. Serve as storage of steam
B. Serve as storage of feed water for water wall
C. Remove salts from water
D. Separate steam from water
Answer : D
20. Thermal equilibrium means that the flow of steam is
A. Isothermal
B. Isentropic
C. Hyperbolic
D. Polytropic
Answer : B
21. The impulse reaction turbine has its driving force
A. As an impulsive force
B. As a reaction force
C. Partly as an impulsive force and partly as a reaction force
D. None of the above
Answer : C
22. The function of injector used in small capacity boilers is to
A. Create vacuum
B. Inject chemical solution in feed pump
C. Pump water, similar to boiler feed pump
D. Add make up water in the system
Answer : C
23. The draught produced by a steam jet issuing from a nozzle placed in the chimney is called
A. Induced steam jet draught
B. Chimney draught
C. Forced steam jet draught
D. None of these
Answer : A
24. The biggest size of thermal power unit operating in India is
A. 30 MW
B. 60 MW
C. 100 MW
D. 500 MW
Answer : D
25. In natural circulation type boiler,
A. Heating takes place at bottom and the water supplied at bottom gets converted into the mixture of steam bubbles and hot water which rise to drum
B. Water is supplied in drum and through down comers located in atmospheric condition it passes to the water wall and rises to drum in the form of mixture of water and steam
C. Feed pump is employed to supplement natural circulation in water wall type furnace
D. Water is converted into steam in one. Pass without any recirculation
Answer : A
26. The average value of diagram factor lies between
A. 0.2 to 0.5
B. 0.5 to 0.65
C. 0.65 to 0.9
D. 0.8 to 1.2
Answer : C
27. The ratio of the useful heat drop to the isentropic heat drop is called
A. Condenser efficiency
B. Nozzle efficiency
C. Boiler efficiency
D. Vacuum efficiency
Answer : B
28. The effect of super-saturation is that the
A. Mass of the steam discharged increases
B. Entropy and specific volume of the steam increases
C. Exit velocity of steam reduces
D. All of these
Answer : D
29. A boiler in India should conform to safety regulations of
A. DIN
B. BS
C. ASTM
D. IBR
Answer : D
30. A supercritical boiler is one that operates above the pressure and temperature of following values
A. 100 kg/cm² and 540°C
B. 1 kg/cm² and 100°C
C. 218 kg/cm² abs and 373°C
D. 218 kg/cm² abs and 540°C
Answer : C
31. The object of producing draught in a boiler is
A. To provide an adequate supply of air for the fuel combustion
B. To exhaust the gases of combustion from the combustion chamber
C. To discharge the gases of combustion to the atmosphere through the chimney
D. All of the above
Answer : D
32. The selection of type and size of a steam boiler depends upon
A. The power required and working pressure
B. The geographical position of the power house
C. The fuel and water available
D. All of the above
Answer : D
33. Feed water conditioning in thermal power plants in done to
A. Reduce hardness and for removal of solids
B. Increase efficiency of thermal power plant
C. Increase heat transfer rate
D. Increase steam parameters
Answer : A
34. Which of the following compound steam engine requires a smaller flywheel?
A. Receiver type
B. Tandem type
C. Woolf type
D. All of these
Answer : A
35. The function of a valve rod is
A. To provide reciprocating motion to the slide valve
B. To convert reciprocating motion of the piston into rotary motion of the crank
C. To convert rotary motion of the crankshaft into to and fro motion of the valve rod
D. To provide simple harmonic motion to the D-slide valve
Answer : D
36. The temperature of flue gases at air heater outlet should be
A. 100°C
B. Above dew point temperature of flue gases
C. Below dew point temperature of flue gases
D. Less than wet bulb temperature of flue gases
Answer : B
37. The equivalent evaporation is defined as
A. The ratio of heat actually used in producing the steam to the heat liberated in the furnace
B. The amount of water evaporated or steam produced in kg per kg of fuel burnt
C. The amount of water evaporated from and at 100°C into dry and saturated steam
D. The evaporation of 15.653 kg of water per hour from and at 100°C
Answer : C
38. In reaction turbines, the axial thrust is due to
A. Pressure drop across the rotor
B. Change in axial velocity
C. Both (A) and (B)
D. None of these
Answer : C
39. The efficiency of an impulse turbine is maximum when (where Vb = Blade speed, V = Absolute velocity of steam entering the blade, and ? = Nozzle angle)
A. Vb = 0.5 V cos?
B. Vb = V cos?
C. Vb = 0.5 V² cos?
D. Vb = V² cos?
Answer : A
40. The diameters of fire tubes and superheater tubes in locomotive boiler are
A. 47.5 mm, 130 mm
B. 32.5 mm, 180 mm
C. 65.5 mm, 210 mm
D. 24.5 mm, 65 mm
Answer : A
41. Which of the following boiler is best suited to meet the fluctuating demand of steam?
A. Locomotive boiler
B. Lancashire boiler
C. Cornish boiler
D. Babcock and Wilcox boiler
Answer : A
42. Cut-off governing of steam engines is a method of controlling the engine output by varying
A. Volume of intake steam
B. Pressure of intake steam
C. Temperature of intake steam
D. All of these
Answer : A
43. Heating of dry steam above saturation temperature is known as
A. Enthalpy
B. Superheating
C. Super saturation
D. Latent heat
Answer : B
44. The equivalent evaporation of a boiler is a measure to compare
A. The given boiler with the model
B. The two different boilers of the same make
C. Two different makes of boilers operating under the same operating conditions
D. Any type of boilers operating under any conditions
Answer : D
45. The capacity of induced draft fan compared to forced draft fan in a boiler is
A. Same
B. More
C. Less
D. Less or more depending on size of boiler
Answer : B
46. The steam leaves the nozzle at a
A. High pressure and a low velocity
B. High pressure and a high velocity
C. Low pressure and a low velocity
D. Low pressure and a high velocity
Answer : D
47. Carbonisation of coal is the process of
A. Pulverising coal in inert atmosphere
B. Heating wood in a limited supply of air at temperatures below 300°C
C. Strongly heating coal continuously for about 48 hours in the absence of air in a closed vessel
D. Binding the pulverised coal into briquettes
Answer : C
48. An ideal regenerative cycle is
A. Equal to Carnot cycle
B. Less than Carnot cycle
C. More than Carnot cycle
D. Could be anything
Answer : B
49. The reheat factor is the ratio of the
A. Cumulative heat drop to the isentropic heat drop
B. Isentropic heat drop to the heat supplied
C. Total useful heat drop to the total isentropic heat drop
D. None of the above
Answer : A
50. The ratio of brake power to the indicated power is known as
A. Mechanical efficiency
B. Overall efficiency
C. Indicated thermal efficiency
D. Brake thermal efficiency
Answer : A

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