1000+ Steam Boilers, Engines, Nozzles & Turbines MCQ for IBPS RRB [Solved]

1. De-Laval turbine is a
A. Simple impulse turbine
B. Simple reaction turbine
C. Impulse-reaction turbine
D. None of these
Answer : A

2. Expanding steam to a very low pressure (high vacuum) in steam engines is
A. Desirable
B. Economical
C. Essential
D. Uneconomical
Answer : D

3. The expansion of steam, as it flows over the blades in reaction turbine, represents
A. Isothermal process
B. Isentropic process
C. Throttling process
D. Free expansion process
Answer : B

4. The high pressure and low pressure cylinders in a receiver type compound engine are regarded as having cranks
A. 180° to each other
B. 90° to each other
C. 0° to each other
D. None of these
Answer : B

5. The steam enters 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 : A

6. The length of shell of a Locomotive boiler is
A. 1 m
B. 2 m
C. 3 m
D. 4 m
Answer : D

7. Lancashire boiler is
A. Stationary fire tube boiler
B. Internally fired boiler
C. Horizontal boiler
D. All of these
Answer : D

8. The actual power generated in the engine cylinder is called
A. Indicated power
B. Brake power
C. Frictional power
D. None of these
Answer : A

9. For the same length of stroke and speed of crankshaft, the piston speed for a double acting steam engine is _________ the piston speed of single acting steam engine.
A. Equal to
B. Twice
C. Three times
D. Four times
Answer : B

10. The size of a boiler drum in pulverised fuel fired boiler, as its size and capacity, (steam pressure and flow ratings) increase
A. Increases
B. Decreases
C. Remains unchanged
D. Increases/decreases depending on steam temperature requirements
Answer : B

11. The dry saturated steam at very high pressure (150200 kg/cm²) when throttled to atmosphere will become
A. Wet
B. Superheated
C. Remain dry saturated
D. Dry
Answer : A

12. The actual vacuum in a condenser is equal to
A. Barometric pressure + actual pressure
B. Barometric pressure - actual pressure
C. Gauge pressure + atmospheric pressure
D. Gauge pressure - atmospheric pressure
Answer : B

13. 100% efficiency of a thermal cycle cannot be achieved because of
A. Frictional losses
B. It is not possible to achieve 0°K temperature
C. Leakage
D. Non availability of ideal substance
Answer : B

14. The blade friction in the impulse turbine reduces the velocity of steam by __________ while it passes over the blades.
A. 10 to 15 %
B. 15 to 20 %
C. 20 to 30 %
D. 30 to 40 %
Answer : A

15. Which device is used in thermal power plants to reduce level of pollution?
A. Induced draft fan
B. Smoke meter
C. Chimney
D. Precipitator
Answer : D

16. Steam turbines may be classified according to
A. Direction of steam flow
B. Number of stages
C. Mode of steam action
D. All of these
Answer : D

17. The fire tubes in a Cochran boiler are
A. Horizontal
B. Vertical
C. Inclined
D. None of these
Answer : A

18. The draught in locomotive boilers is produced by a
A. Chimney
B. Centrifugal fan
C. Steam jet
D. None of these
Answer : C

19. Tertiary air is the air used to
A. Provide air around burners for obtaining optimum combustion
B. Transport and dry the coal
C. Cool the scanners
D. Convert CO (formed in lower zone of furnace) into CO? at higher zone.
Answer : D

20. The velocity of flue gases (V) through the chimney under a static draught of (H') metres is given by
A. V = 2g H'
B. V = 2g/H'
C. V = H'/2g
D. V = 2gH'
Answer : A

21. While steam expands in turbines, theoretically the entropy
A. Remains constant
B. Increases
C. Decreases
D. Behaves unpredictably
Answer : A

22. The radius of a dished head is taken approximately as
A. One fourth
B. Half
C. One
D. Two
Answer : C

23. Vacuum for reciprocating steam engines compared to steam turbines is
A. More
B. Equal
C. Less
D. Could be more or less depending on the size of plant
Answer : C

24. In an ideal impulse turbine, the
A. Absolute velocity at the inlet of moving blade is equal to that at the outlet
B. Relative velocity at the inlet of the moving blade is equal to that at the outlet
C. Axial velocity at inlet is equal to that at the outlet
D. Whirl velocity at inlet is equal to that at the outlet
Answer : B

25. The ratio of total useful heat drop to the total isentropic heat drop, is called
A. Stage efficiency
B. Internal efficiency
C. Rankine efficiency
D. None of these
Answer : B

26. The heat balance sheet for the boiler shows the
A. Complete account of heat supplied by 1 kg of dry fuel and the heat consumed
B. Moisture present in the fuel
C. Steam formed by combustion of hydrogen per kg of fuel
D. All of the above
Answer : A

27. The dry saturated steam at very low pressure, (510 kg/cm²) when throttled to atmosphere will become
A. Wet
B. Superheated
C. Remain dry saturated
D. Dry
Answer : B

28. 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

29. The bituminous coal is no caking if its carbon content is
A. 78-81 %
B. 81-85 %
C. 85-90 %
D. 90-95 %
Answer : A

30. Thermal efficiency of a thermal power plant is of the order of
A. 15 %
B. 20 %
C. 30 %
D. 45 %
Answer : C

31. The friction in the nozzle __________ exit velocity of steam.
A. Has no effect on
B. Decreases
C. Increases
D. None of these
Answer : B

32. Hard coke is used in
A. Cement industry
B. Thermal power plant
C. Blast furnace
D. Domestic use
Answer : C

33. 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

34. The balanced draft furnace is one using
A. Induced draft fan and chimney
B. Induced draft fan and forced draft fan
C. Forced draft fan and chimney
D. Any one of the above
Answer : B

35. The flow of steam is supersonic
A. At the entrance to the nozzle
B. At the throat of the nozzle
C. In the convergent portion of the nozzle
D. In the divergent portion of the nozzle
Answer : D

36. In accelerated 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 : B

37. Green coal, in order to be burnt, must be
A. Heated sufficiently
B. Burnt in excess air
C. Heated to its ignition point
D. Burnt as powder
Answer : C

38. The high steam and low water safety valve is not used in
A. Cochran boiler
B. Cornish boiler
C. Lancashire boiler
D. Locomotive boiler
Answer : D

39. During polytropic process
A. Heat transfer takes place across cylinder walls
B. Work is done
C. Steam may be wet, dry or superheated after expansion
D. All of the above
Answer : D

40. Which of the following is not a boiler mounting?
A. Blow off cock
B. Feed check valve
C. Economiser
D. Fusible plug
Answer : C

41. 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

42. Lancashire boiler is a
A. Stationary fire tube boiler
B. Stationary water tube boiler
C. Water tube boiler with natural/forced circulation
D. Mobile fire tube boiler
Answer : A

43. A double acting steam engine with a cylinder diameter of 190 mm and a stroke of 300 mm has a cut-off of 0.35. The expansion ratio for this engine is nearly
A. 1.05
B. 2.86
C. 6.65
D. 10.05
Answer : B

44. The proximate analysis of fuel lists
A. Various chemical constituents, carbon, hydrogen, oxygen etc, plus ash as percents by volume
B. Various chemical constituents, carbon, hydrogen, oxygen, etc, plus ash as percents by weight
C. Fuel constituents as percents by volume of moisture, volatile, fixed carbon and ash
D. Fuel constituents as percents by weight of moisture, volatile, fixed carbon and ash
Answer : D

45. Which of the following is a fire tube boiler?
A. Locomotive boiler
B. Babcock and Wilcox boiler
C. Stirling boiler
D. All of the above
Answer : A

46. The height of chimney in a power plant is governed by
A. The draft to be created
B. Limitation of construction facilities
C. Control of pollution
D. Quantity of flue gases to be handled
Answer : C

47. Willian's law states that the steam consumption per hour provided with a throttled governor is proportional to (where I.P. = Indicated power)
A. 1/(I.P)
B. 1/(I.P)²
C. I.P.
D. (I.P.)²
Answer : C

48. The supersaturated flow of steam through a nozzle as compared to a stable flow, the available heat drop
A. Remains the same
B. Increases
C. Decreases
D. Is unpredictable
Answer : C

49. The theoretical indicator diagram of a simple steam engine is based upon the assumption that
A. There is no pressure drop due to condensation
B. Steam is admitted at boiler pressure and exhausted at condenser pressure
C. The expansion (or compression) of the steam is hyperbolic
D. All of the above
Answer : D

50. 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