1000+ Steam Boilers, Engines, Nozzles & Turbines Multiple Choice Question Answer [Solved]

1. The ratio of the workdone on the blades to the energy supplied to the blades, is called
A. Blading efficiency
B. Nozzle efficiency
C. Gross or stage efficiency
D. Mechanical efficiency
Answer : A

2. The critical pressure ratio for initially superheated steam is __________ as compared to initially dry saturated steam.
A. More
B. Less
C. Same
D. None of these
Answer : B

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 efficiency of the plant __________ with the mechanical draught.
A. Increases
B. Decreases
C. Remains constant
D. None of these
Answer : A

5. The function of a crosshead is to guide motion of the _________ and to prevent it from bending.
A. Piston rod
B. Connecting rod
C. Eccentric rod
D. Valve rod
Answer : A

6. Heating of dry steam above saturation temperature is known as
A. Enthalpy
B. Superheating
C. Super saturation
D. Latent heat
Answer : B

7. The maximum efficiency of a reaction turbine is
A. 2 sin²?/(1 + sin²?)
B. 2 cos²?/(1 + cos²?)
C. (1 + sin²?)/2 sin²?
D. (1 + cos²?)/2 cos²?
Answer : B

8. 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

9. In a Tandem type compound engine, the high pressure and low pressure cylinders
A. Have common piston rod
B. Are set at 90°
C. Have separate piston rods
D. Are set in V-arrangement
Answer : A

10. O? content in atmospheric air on volume basis is
A. 21 %
B. 23 %
C. 30 %
D. 40 %
Answer : A

11. When steam after doing work in the cylinder passes into a condenser, the engine is said to be a
A. Slow speed engine
B. Vertical steam engine
C. Condensing steam engine
D. Non-condensing steam engine
Answer : C

12. In impulse turbines, when friction is neglected, the relative velocity of steam at outlet tip of the blade is __________ the relative velocity of steam at inlet tip of the blade.
A. Equal to
B. Less than
C. Greater than
D. None of these
Answer : A

13. In a 50% reaction turbine stage, tangential component of absolute velocity at rotor inlet is 537 m/s and the blade velocity is 454 m/s. The power output in kW of steam will be
A. 260 kW
B. 282 kW
C. 296 kW
D. 302 kW
Answer : B

14. The state of vapour under saturation condition is described by
A. Pressure alone
B. Temperature alone
C. Pressure and temperature
D. Pressure and dryness fraction
Answer : D

15. 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

16. The critical pressure gives the velocity of steam at the throat
A. Equal to the velocity of sound
B. Less than the velocity of sound
C. More than the velocity of sound
D. None of these
Answer : A

17. A compound steam engine in which the high pressure and low pressure cylinders have common piston rod, is called
A. Receiver type compound engine
B. Tandem type compound engine
C. Woolf type compound engine
D. None of these
Answer : B

18. In a throttling process
A. Steam temperature remains constant
B. Steam pressure remains constant
C. Steam enthalpy remains constant
D. Steam entropy remains constant
Answer : C

19. The device attached to the steam chest for preventing explosions due to excessive internal pressure of steam is called
A. Safety valve
B. Water level indicator
C. Pressure gauge
D. Fusible plug
Answer : A

20. An economiser _________ the steam raising capacity of a boiler.
A. Increases
B. Decreases
C. Has no effect on
D. None of these
Answer : A

21. The velocity of whirl at outlet for an axial discharge turbine is
A. Minimum
B. Maximum
C. Zero
D. None of these
Answer : C

22. The ratio of the isentropic heat drop to the heat supplied, is called
A. Reheat factor
B. Stage efficiency
C. Internal efficiency
D. Rankine efficiency
Answer : D

23. Lancashire boiler is of
A. Stationary < fire tube type
B. Horizontal type
C. Natural circulation type
D. All of the above
Answer : D

24. 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

25. Water at pressure of 4 kg/cm² and 160°C temperature when exposed to atmosphere will
A. Boil
B. Flash i.e. get converted into steam
C. Remain as it was
D. Cool down
Answer : B

26. 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

27. Which is not correct statement about the function of furnace?
A. To provide proper conditions for continuous complete combustion
B. Mix fuel with air and ignite
C. Separate ash from coal
D. Maintain heat supply to prepare and ignite the incoming fuel
Answer : C

28. Which of the following statement is correct?
A. A fire tube boiler occupies less space than a water tube boiler, for a given power.
B. Steam at a high pressure and in large quantities can be produced with a simple vertical boiler.
C. A simple vertical boiler has one fire tube.
D. All of the above
Answer : C

29. 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

30. Duplex feed pumps are used in small steam boilers. These operate on the principle of
A. Centrifugal pump
B. Axial flow pump
C. Gear pump
D. Reciprocating pump
Answer : D

31. The critical pressure at which latent heat of vaporisation is zero is
A. 225.65 kgf/ cm²
B. 273 kgf/ cm²
C. 100 kgf/ cm²
D. 1 kgf/ cm²
Answer : A

32. The purpose of governing in steam turbines is to
A. Maintain the speed of the turbine
B. Reduce the effective heat drop
C. Reheat the steam and improve its quality
D. Completely balance against end thrust
Answer : A

33. The expansion of steam in a nozzle follows
A. Carnot cycle
B. Rankine cycle
C. Joule cycle
D. Stirling cycle
Answer : B

34. Which of the following substance will have same percentage in both proximate and ultimate analysis?
A. Ash
B. Volatile matter
C. Moisture
D. Hydrogen
Answer : A

35. The number of drums in Benson steam generator is
A. One
B. Two
C. One steam drum and one water drum
D. No drum
Answer : D

36. For maximum discharge through a chimney, the condition is that height of hot gas column producing the draught should be
A. One-half the height of chimney
B. Equal to the height of chimney
C. Two times the height of chimney
D. Four times the height of chimney
Answer : B

37. The artificial draught is produced by
A. Steam jet
B. Centrifugal fan
C. Chimney
D. Both (A) and (B)
Answer : D

38. Which of the following is a fire tube boiler?
A. Lancashire boiler
B. Babcock and Wilcox boiler
C. Yarrow boiler
D. None of these
Answer : A

39. A stage, in reaction turbine, is represented by
A. Number of casing
B. Number of entries of steam
C. Number of exits of steam
D. Each row of blades
Answer : D

40. Spontaneous combustion is a phenomenon in which
A. All the fuel burns instantaneously producing high energy release
B. Fuel burns with less air
C. Coal bursts into flame without any external ignition source but by itself due to gradual increase in temperature as a result of heat released by combination of oxygen with coal
D. Explosion in furnace
Answer : C

41. Willians line follows the law (where b = A constant representing the shape of the Willians line, a = Another constant i.e. no load consumption per hour, I.P. = Indicated power, and m = Steam consumption per hour)
A. I.P. = a × m + b
B. m = a + b × I.P.
C. I.P. = b × m + a
D. m = (b/I.P.) - a
Answer : B

42. The diameter of tubes for natural circulation boiler as compared to controlled circulation boilers is
A. More
B. Less
C. Same
D. Could be more or less depending on other factors
Answer : A

43. The critical pressure ratio for gases is
A. 0.528
B. 0.546
C. 0.577
D. 0.582
Answer : A

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

45. 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

46. All steam engines work on
A. Zeroth law of thermodynamics
B. First law of thermodynamics
C. Second law of thermodynamics
D. None of these
Answer : C

47. The diameter of Cornish boiler is of the order of
A. 12 m
B. 1.52.5 m
C. 23 m
D. 2.53.5 m
Answer : A

48. 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

49. The draught produced by a steam jet issuing from a nozzle placed in the ash-pit under the fire grate of the furnace is called
A. Induced steam jet draught
B. Chimney draught
C. Forced steam jet draught
D. None of these
Answer : C

50. The crown of the fire box is made hemispherical in order to
A. Give maximum space
B. Give maximum strength
C. Withstand pressure inside boiler
D. Resist intense heat in fire box
Answer : D