SSC Stenographer - Steam Boilers, Engines, Nozzles & Turbines 1000+ MCQ [Solved] PDF Download

1. 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

2. Film boiling occurs at
A. Very low pressure
B. Atmospheric pressures
C. Medium pressures
D. Very high pressures
Answer : D

3. The draught (in mm of water), for maximum discharge of flue gases through the chimney, is given by (where H = Height of the chimney in metres, and T₁ = Absolute temperature of air outside the chimney in K)
A. T₁ /88.25H
B. 88.25H/T₁
C. T₁ /176.5H
D. 176.5H/T₁
Answer : D

4. 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

5. 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

6. The condition of steam in boiler drum is always
A. Dry
B. Wet
C. Saturated
D. Supersaturated
Answer : B

7. The process of draining steam from the turbine, at certain points during its expansion and using this steam for heating the feed water in feed water heaters and then supplying it to the boiler is known as
A. Regenerative heating
B. Reheating of steam
C. Bleeding
D. None of these
Answer : C

8. 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

9. In water tube boilers
A. Water passes through the tubes which are surrounded by flames and hot gases
B. The flames and hot gases pass through the tubes which are surrounded by water
C. Forced circulation takes place
D. None of these
Answer : A

10. Which of the following statement is correct for a compound steam engine?
A. The cost of the engine, for the same power and economy, is more than that of a simple steam engine.
B. The forces in the working parts are increased as the forces are distributed over more parts.
C. The ratio of expansion is reduced, thus reducing the length of stroke.
D. The temperature range per cylinder is increased, with corresponding increase in condensation.
Answer : C

11. The maximum steam pressure in a Locomotive boiler is limited to
A. 0.18 MN/m²
B. 1.8 MN/m²
C. 18 MN/m²
D. 180 MN/m²
Answer : B

12. 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

13. 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

14. Which of the following is required for a steam condensing plant?
A. Condenser
B. Condensate pump
C. Air extraction pump
D. All of these
Answer : D

15. A compound steam engine in which piston rods of high pressure and low pressure cylinders are attached to two different cranks set at 90° to each other, is called
A. Receiver type compound engine
B. Tandem type compound engine
C. Woolf type compound engine
D. Both (A) and (B)
Answer : A

16. The velocity of steam at throat of the nozzle is __________ the velocity of sound.
A. Equal to
B. Less than
C. More than
D. None of these
Answer : A

17. 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

18. 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

19. 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

20. The working pressure range for a LaMont boiler is
A. 0.5 to 10 MN/m²
B. 1 to 15 MN/m²
C. 2.5 to 15 MN/m²
D. 3.5 to 20 MN/m²
Answer : D

21. In order to reduce the rotor speed of an impulse turbine, the method employed is
A. Velocity compounding
B. Pressure compounding
C. Pressure-velocity compounding
D. All of these
Answer : D

22. Throttle 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 : B

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. Caking coals are those which
A. Form lumps or masses of coke
B. Burn freely
C. Show little or no fusing action
D. Burn completely
Answer : A

25. The effect of friction on the flow of steam through a nozzle is to
A. Decrease the mass flow rate and to increase the wetness of steam
B. Increase the mass flow rate and to increase the exit temperature
C. Decrease the mass flow rate and to decrease the wetness of steam
D. Increase the exit temperature without any effect on mass flow rate
Answer : C

26. A condenser in a steam power plant
A. Increases expansion ratio of steam
B. Reduces back pressure of steam
C. Reduces temperature of exhaust steam
D. All of these
Answer : D

27. A boiler in India should conform to safety regulations of
A. DIN
B. BS
C. ASTM
D. IBR
Answer : D

28. 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

29. 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

30. Pick up the wrong statement about critical condition of steam
A. Latent heat is zero
B. Liquid directly becomes steam
C. Specific volume of steam and liquid is same
D. This is the maximum pressure limit
Answer : D

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

32. Feed water conditioning in thermal power plants in done to
A. Reduce hardness and for removal of solids
B. Increase efficiency of thermal power plant
C. Increase heat transfer rate
D. Increase steam parameters
Answer : A

33. The ratio of the volume at cut-off to the swept volume is called
A. Cut-off ratio
B. Expansion ratio
C. Clearance ratio
D. None of these
Answer : A

34. Primary 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 forced draft fan
Answer : B

35. The flow through a nozzle is regarded as
A. Constant volume flow
B. Constant pressure flow
C. Isothermal flow
D. Isentropic flow
Answer : D

36. 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

37. 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

38. 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

39. 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

40. The function of a piston in a steam engine is
A. To guide motion of the piston rod and to prevent it from bending
B. To transfer motion from the piston to the crosshead
C. To convert heat energy of the steam into mechanical work id) to exhaust steam from the cylinder at proper moment
D. None of these
Answer : C

41. The function of a piston rod is
A. To guide motion of the piston rod and to prevent it from bending
B. To transfer motion from the piston to the cross head
C. To convert heat energy of the steam into mechanical work
D. To exhaust steam from the cylinder at proper moment
Answer : B

42. 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

43. Cochran boiler is a
A. Horizontal fire tube boiler
B. Horizontal water tube boiler
C. Vertical water tube boiler
D. Vertical fire tube boiler
Answer : D

44. The turbine blades are
A. Straight
B. Circular
C. Curved
D. None of these
Answer : C

45. 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

46. 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

47. The diameter of internal flue tubes in a Lancashire boiler compared to its shell is
A. One-half
B. One-third
C. Two-fourth
D. Two-fifth
Answer : D

48. The length of Lancashire boiler varies from
A. 5 to 6 m
B. 6 to 7 m
C. 7.25 to 9 m
D. 9 to 10 m
Answer : C

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

50. A device used in a boiler to control the flow of steam from the boiler to the main pipe and to shut off the steam completely when required, is known as
A. Blow off cock
B. Fusible plug
C. Superheater
D. Stop valve
Answer : D