Steam Boilers, Engines, Nozzles & Turbines MCQ Solved Paper for SSC GD

1. The coal requirement per kW hour generation in the thermal power plant is of the order of
A. 0.1 to 0.2 kg
B. 0.2 to 0.4 kg
C. 0.6 to 0.8 kg
D. 1.0 to 1.5 kg
Answer : C

2. The power of a boiler may be 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 : B

3. Water tube boilers are
A. Internally fired
B. Externally fired
C. Internally as well as externally fired
D. None of these
Answer : B

4. 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

5. Which of the following statement is correct for steam turbines as compared to reciprocating steam engines?
A. A steam turbine develops higher speeds
B. The efficiency of steam turbine is higher
C. The steam consumption is less
D. All of these
Answer : D

6. One kg of steam sample contains 0.8 kg dry steam; Its dryness fraction is
A. 0.2
B. 0.8
C. 1.0
D. 0.6
Answer : B

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

8. 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

9. Water tube boilers are those in which
A. Flue gases pass through tubes and water around it
B. Water passes through the tubes and flue gases around it
C. Work is done during adiabatic expansion
D. Change in enthalpy
Answer : C

10. The pressure velocity compounded impulse turbine allows a bigger pressure drop and hence __________ numbers of stages are required.
A. More
B. Less
C. Equal
D. None of these
Answer : B

11. 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

12. In designing air preheaters, the important design consideration is that
A. Approach temperature should be as low as possible
B. Handling and maintenance should be easier
C. Heat transfer area should be optimum
D. Stack gases should not be cooled to the dew point
Answer : D

13. Multi-stage steam turbines are of the
A. Velocity compounded type
B. Reaction type
C. Pressure compounded type
D. All of these
Answer : D

14. The effect of friction in the nozzle __________ dryness fraction of steam.
A. Has no effect on
B. Decreases
C. Increases
D. None of these
Answer : C

15. Proximate analysis of fuel is determination of percentage of
A. Carbon, hydrogen, nitrogen, sulphur, moisture
B. Fixed carbon, ash, volatile matter, moisture
C. Higher calorific value
D. Lower calorific value
Answer : B

16. Incomplete combustion can be best judged by
A. Smoky chimney exit
B. Excess air in flue gases
C. Measuring carbon monoxide in flue gases
D. Measuring temperature of flue gases at exit of furnace
Answer : C

17. 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

18. Mechanical equivalent of heat for 1 kcal or Joule's equivalent is equal to
A. 421 kg.m
B. 421 kg.m
C. 539 kg.m
D. 102 kg.m
Answer : A

19. Which of the following boiler works on a forced circulation of water?
A. Lamont boiler
B. Benson boiler
C. Loeffler boiler
D. All of these
Answer : D

20. The three Ts for good combustion are
A. Temperature, time, and turbulence
B. Total air, true fuel, and turbulence
C. Thorough mixing, total air and temperature
D. Total air, time, and temperature
Answer : A

21. The ratio of heat equivalent to brake power to the energy supplied in steam is known as
A. Mechanical efficiency
B. Overall efficiency
C. Indicated thermal efficiency
D. Brake thermal efficiency
Answer : D

22. The length of Cornish boiler is of the order of
A. 24 m
B. 35 m
C. 57.5 m
D. 79 m
Answer : C

23. An impulse turbine as compared to a reaction turbine, for a given power has _________ row of blades.
A. Equal
B. Less
C. More
D. None of these
Answer : C

24. 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

25. 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

26. A device in which some portion of waste heat of flue gases is recovered to heat the air before it passes to the furnace for combustion purpose, is known as
A. Superheater
B. Air-preheater
C. Economiser
D. Injector
Answer : B

27. The stage efficiency (?_S) is given by (where ?_B = Blading efficiency, and ?_N = Nozzle efficiency)
A. ?_S = ?_B × ?_N
B. ?_S = ?_B / ?_N
C. ?_S = ?_N / ?_B
D. None of these
Answer : A

28. The reheat factor depends upon
A. Initial pressure and superheat
B. Exit pressure
C. Turbine stage efficiency
D. All of these
Answer : D

29. The Parsons' reaction turbine has
A. Only moving blades
B. Only fixed blades
C. Identical fixed and moving blades
D. Fixed and moving blades of different shape
Answer : C

30. The fusible plug in small boilers is located
A. In the drum
B. In the fire tubes
C. Above steam dome
D. Over the combustion chamber
Answer : D

31. 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

32. In water wall furnace, the heat is transferred to the water walls by
A. Convection
B. Radiation
C. Conduction
D. Radiation and conduction
Answer : B

33. In a steam engine, superheated steam from the boiler is fed into the steam chest at a pressure of
A. 10 atmospheres
B. 20 atmospheres
C. 30 atmospheres
D. 40 atmospheres
Answer : B

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

35. Secondary air is the air used to
A. Provide air around burners for obtaining optimum combustion
B. Transport and dry the coal
C. Convert CO (formed in lower zone of furnace) into CO? at higher zone
D. Air delivered by induced draft fan
Answer : A

36. When the cross-section of a nozzle increases continuously from entrance to exit, it is called a
A. Divergent nozzle
B. Convergent nozzle
C. Convergent-divergent nozzle
D. None of these
Answer : A

37. The pressure compounded impulse turbine as compared to velocity compounded turbine require __________ number of stages.
A. Same
B. Less
C. More
D. None of these
Answer : C

38. 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

39. The critical pressure ratio for initially wet steam is
A. 0.546
B. 0.577
C. 0.582
D. 0.601
Answer : C

40. In a single acting steam engine
A. The steam is admitted on one side of the piston and one working stroke is produced during each revolution of the crankshaft
B. The steam is admitted, in turn, on both sides of the piston and one working stroke is produced during each revolution of the crankshaft
C. The steam is admitted on one side of the piston and two working strokes are produced during each revolution of the crankshaft
D. The steam is admitted, in turn, on both sides of the piston and two working strokes are produced during each revolution of the crankshaft
Answer : A

41. The safety valve on boiler drum compared to safety valve on superheater is set at
A. Same value
B. Higher value
C. Lower value
D. Lower/higher depending on steam flow
Answer : B

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

43. Alkaline pyrogallate is used in Orsat's apparatus for absorption of
A. CO?
B. CO
C. O?
D. N?
Answer : C

44. In turbines, the fluid undergoes a continuous steady flow process and the speed of flow is
A. Low
B. Very low
C. High
D. Very high
Answer : D

45. Reheating of steam under ideal conditions takes place at constant
A. Entropy
B. Enthalpy
C. Pressure
D. Temperature
Answer : D

46. The critical pressure ratio for initially dry saturated steam is
A. 0.546
B. 0.577
C. 0.582
D. 0.601
Answer : B

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. Which of the following statement is wrong?
A. Locomotive boiler is a water tube boiler
B. Water tube boilers are internally fired
C. Lamont boiler is a low pressure water tube boiler
D. All of the above
Answer : D

49. De-Laval turbines are mostly used
A. Where low speeds are required
B. For small power purposes and low speeds
C. For large power purposes
D. For small power purposes and high speeds
Answer : D

50. There is always some steam left in the clearance space from the previous stroke. This steam left in the clearance space is called
A. Wet steam
B. Saturated steam
C. Superheated steam
D. Cushion steam
Answer : D