Steam Boilers, Engines, Nozzles & Turbines MCQ Solved Paper for LSAT

1. For combustion of a fuel, following is essential
A. Correct fuel air ratio
B. Proper ignition temperature
C. O? to support combustion
D. All the three above
Answer : D

2. The diagram factor is the ratio of the
A. Area of the actual indicator diagram to the area of theoretical indicator diagram
B. Actual workdone per stroke to the theoretical workdone per stroke
C. Actual mean effective pressure to the theoretical mean effective pressure
D. Any one of the above
Answer : D

3. The Locomotive boiler has
A. 137 fire tubes and 44 superheated tubes
B. 147 fire tubes and 34 superheated tubes
C. 157 fire tubes and 24 superheated tubes
D. 167 fire tubes and 14 superheated tubes
Answer : C

4. 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

5. At which pressure the properties of water and steam become identical
A. 0.1 kg/cm²
B. 1 kg/cm²
C. 100 kg/cm²
D. 225.6 kg/cm²
Answer : D

6. De-Laval turbine is a
A. Single rotor impulse turbine
B. Multi-rotor impulse turbine
C. Impulse reaction turbine
D. None of these
Answer : A

7. The specific volume of steam with increase in pressure decreases
A. Linearly
B. Slowly first and then rapidly
C. Rapidly first and then slowly
D. Inversely
Answer : C

8. 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

9. The chimney draught varies with
A. Climatic conditions
B. Temperature of furnace gases
C. Height of chimney
D. All of these
Answer : D

10. 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

11. 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

12. 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

13. In a reaction turbine, when steam flows through the fixed blades,
A. Pressure increases while velocity decreases
B. Pressure decreases while velocity increases
C. Pressure and velocity both decreases
D. Pressure and velocity both increases
Answer : B

14. Which is not correct statement about pulverised fuel firing?
A. High burning rate is possible
B. Heat release can be easily controlled
C. Fuel burns economically
D. It is the best technique for burning high ash content fuel having low fusion ash
Answer : D

15. The difference of supersaturated temperature and saturation temperature at that pressure is called
A. Degree of super-saturation
B. Degree of superheat
C. Degree of under-cooling
D. None of these
Answer : C

16. Sublimation region is the region where
A. Solid and vapour phases are in equilibrium
B. Solid and liquid phases are in equilibrium
C. Liquid and vapour phases are in equilibrium
D. Solid, liquid and vapour phases are in equilibrium
Answer : A

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

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

19. Heating wet steam at constant temperature is heating it at constant
A. Volume
B. Pressure
C. Entropy
D. Enthalpy
Answer : B

20. 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

21. The behaviour of coal in a furnace is determined by
A. The content of sulphur
B. The content of ash and heating value
C. The proximate analysis
D. The exact analysis
Answer : C

22. 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

23. Degree of reaction is defined as the ratio of
A. Heat drop in fixed blades to the heat drop in moving blades
B. Heat drop in moving blades to the heat drop in fixed blades
C. Heat drop in moving blades to the heat drop in fixed blades plus heat drop in moving blades
D. Heat drop in fixed blades plus heat drop in moving blades to the heat drop in moving blades
Answer : C

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

25. When the back pressure of a nozzle is below the designed value of pressure at exit of nozzle, the nozzle is said to be
A. Choked
B. Under-damping
C. Over-damping
D. None of these
Answer : B

26. One kilowatt-hour energy is equivalent to
A. 1000 J
B. 360 kJ
C. 3600 kJ
D. 3600 kW/sec
Answer : C

27. Boiler stays are used to
A. Prevent flat surfaces under pressure from tearing apart
B. Take care of failure in shear
C. Take care of failure in compression
D. Provide support for boiler
Answer : A

28. Gusset stays in a boiler are provided to
A. Prevent the bulging of flat surfaces
B. Avoid explosion in furnace
C. Prevent leakage of hot flue gases
D. Support furnace freely from top
Answer : A

29. Which of the following coals has the highest calorific value?
A. Anthracite coal
B. Bituminous coal
C. Lignite
D. Peat
Answer : A

30. 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

31. A safety valve in a locomotive starts leaking. The leaking medium will be
A. Water
B. Dry steam
C. Wet steam
D. Super heated steam
Answer : D

32. 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

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. Desecration of feed water is carried out because it reduces
A. Cavitation of boiler feed pumps
B. Corrosion caused by oxygen
C. Heat transfer coefficient
D. pH value of water
Answer : B

35. 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

36. In order to obtain superheated steam, a superheater is added in an existing boiler. As as result, furnace vacuum will
A. Remain unaffected
B. Improve
C. Worsen
D. May improve/worsen depending on size
Answer : C

37. When the circulation of water, in a boiler, is by convection currents which are set up during the heating of water, then the boiler is known as
A. Internally fired boiler
B. Externally fired boiler
C. Natural circulation boiler
D. Forced circulation boiler
Answer : C

38. An economiser in a boiler
A. Increases steam pressure
B. Increases steam flow
C. Decreases fuel consumption
D. Decreases steam pressure
Answer : C

39. 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

40. 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

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

42. 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

43. Steam in water tube boiler as compared to fire tube boiler
A. Can be raised rapidly
B. Is raised at slower rate
C. Is raised at same rate
D. Could be raised at fast/slow rate depending on design
Answer : A

44. An air preheater
A. Increases evaporative capacity of the boiler
B. Increases the efficiency of the boiler
C. Enables low grade fuel to be burnt
D. All of the above
Answer : D

45. Sulphur in coal results in
A. Corroding air heaters
B. Spontaneous combustion during coal storage
C. Facilitating ash precipitation
D. All of the above
Answer : D

46. 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

47. 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

48. 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

49. 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

50. 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