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

1. Pick up the correct statement as regards Cornish boiler and Lancashire boiler
A. Cornish is fire tube and Lancashire is water tube
B. Cornish is water tube and Lancashire is fire tube
C. Cornish has two fire tubes and Lancashire has one
D. Lancashire has two fire tubes and Cornish has one
Answer : D

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

3. Over fire burning is the phenomenon of
A. Supply of excess, air
B. Supply of excess coal
C. Burning CO and unburnts in upper zone of furnace by supplying more air
D. Fuel bed firing
Answer : C

4. Size of boiler tubes is specified by
A. Mean diameter and thickness
B. Inside diameter and thickness
C. Outside diameter and thickness
D. Outside diameter and inside diameter
Answer : C

5. The critical pressure ratio (p?/p?) is given by
A. (p?/p?) = [2/(n - 1)] ^{n/(n + 1)}
B. (p?/p?) = [2/(n + 1)] ^n/(n-1)
C. (p?/p?) = [(n - 1)/2] ^{n + (1/n)}
D. (p?/p?) = [(n + 1)/2] ^{n - (1/n)}
Answer : B

6. The ratio of the actual vacuum to the ideal vacuum in a condenser is called
A. Condenser efficiency
B. Vacuum efficiency
C. Nozzle efficiency
D. Boiler efficiency
Answer : B

7. 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

8. The ratio of heat actually used in producing the steam to the heat liberated in the furnace, is known as
A. Equivalent evaporation
B. Factor of evaporation
C. Boiler efficiency
D. Power of a boiler
Answer : C

9. 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

10. The pressure of steam in the engine cylinder at the beginning of the stroke is ________ the boiler pressure.
A. Equal to
B. Less than
C. Higher than
D. None of these
Answer : B

11. The maximum heat loss is a boiler occurs due to
A. Moisture in fuel
B. Dry flue gases
C. Steam formation
D. Unburnt carbon
Answer : B

12. Blow off cock in a boiler is used to
A. Control the flow of steam from the boiler to the main pipe and to shut off the steam completely when required
B. Empty the boiler when required and to discharge the mud, scale or sediments which are accumulated at the bottom of the boiler
C. Put off fire in the furnace of the boiler when the level of water in the boiler falls to an unsafe limit
D. Increase the temperature of saturated steam without raising its pressure
Answer : B

13. 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

14. At very low temperature, the melting and boiling temperatures become equal. This temperature is
A. 373°K
B. 273.16°K
C. 303°K
D. 0°K
Answer : B

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

16. Boiler parameters are expressed by
A. Tonnes/hr. of steam
B. Pressure of steam in kg/cm²
C. Temperature of steam in °C
D. All of the above
Answer : D

17. In recuperative air preheaters, the heat is transferred
A. From a metal wall from one medium to another
B. From heating an intermediate material and then heating the air from this material
C. By direct mixing,
D. Heat is transferred by bleeding some gases from furnace
Answer : A

18. The cylinder dimensions of a compound engine may be designed on the basis of
A. Equal power developed in each cylinder for uniform turning moment
B. Equal initial piston loads on all pistons for obtaining same size of piston rod, connecting rod etc. for all cylinders
C. Equal temperature drop in each cylinder for economy of steam
D. All of the above
Answer : D

19. During storage, the heating value of coal
A. Increases
B. Decreases
C. Remain constant
D. May increase or decrease depending upon the method of storage
Answer : B

20. The diameter of a cylindrical shell of a Scotch marine boiler varies from
A. 1.5 to 2 m
B. 2.5 to 3.5 m
C. 3.5 to 4.5 m
D. None of these
Answer : B

21. Hygrometry deals with the
A. Hygroscopic substances
B. Water vapour in air
C. Temperature of air
D. Pressure of air
Answer : B

22. A nozzle is said to be a convergent nozzle
A. When the cross-section of the nozzle increases continuously from entrance to exit
B. When the cross-section of the nozzle decreases continuously from entrance to exit
C. When the cross-section of the nozzle first decreases from entrance to throat and then increases from its throat to exit
D. None of the above
Answer : B

23. 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

24. On Mollier chart, free expansion, or throttling process from high pressure to atmosphere is represented by
A. Horizontal straight line
B. Vertical straight line
C. Straight inclined line
D. Curved line
Answer : A

25. In a De-Laval nozzle expanding superheated steam from 10 bar to 0.1 bar, the pressure at the minimum cross-section (i. e. pressure at throat, p?) will be
A. 3.3 bar
B. 5.46 bar
C. 8.2 bar
D. 9.9 bar
Answer : B

26. 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

27. The heat loss in a boiler takes place in the form of
A. Heat carried away by flue gases
B. Heat carried away by ash
C. Moisture present in fuel and steam formed by combustion of hydrogen in fuel
D. All of the above
Answer : D

28. 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

29. 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

30. 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

31. 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

32. 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

33. The evaporation of 15.653 kg of water per hour from and at 100°C is called
A. Evaporative capacity
B. Factor of evaporation
C. Equivalent evaporation
D. One boiler h.p.
Answer : D

34. 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

35. At critical point, i.e. p = 225.65 kg/cm², the latent enthalpy of vaporisation is
A. Maximum
B. Minimum
C. Zero
D. Depends on temperature also
Answer : C

36. Stoichiometric quantity of air is the
A. Air present in atmosphere at NTP conditions
B. Air required for complete combustion of fuel with no excess air
C. Air required for optimum combustion so as to have reasonable excess air
D. Air required to convert CO into CO?
Answer : B

37. 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

38. Pick up the wrong statement about water tube boiler in comparison to fire tube boilers
A. Former occupies less space for same power
B. Rate of steam flow is more in former case
C. Former is used for high installed capacity
D. Chances of explosion are less in former case.
Answer : D

39. 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

40. In which of the following boilers, the draught in furnace is increased by utilising exhaust steam from engine
A. Lancashire boiler
B. Locomotive boiler
C. Babcock and Wilcox boiler
D. Benson boiler
Answer : B

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

42. 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

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 efficiency of a pressure-velocity compounded impulse turbine is __________ as compared to pressure compounded impulse turbine.
A. Same
B. Less
C. More
D. None of these
Answer : B

45. In a steam condenser, the partial pressure of steam and air are 0.06 bar and 0.007 bar respectively. The condenser pressure is
A. 0.007 bar
B. 0.053 bar
C. 0.06 bar
D. 0.067 bar
Answer : D

46. 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

47. 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

48. Blading efficiency is also known as
A. Stage efficiency
B. Diagram efficiency
C. Nozzle efficiency
D. None of these
Answer : B

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

50. 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