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

1. 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

2. 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

3. 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

4. Lancashire boiler is used where working pressure and power required are
A. Low
B. Moderate
C. High
D. None of these
Answer : B

5. Which of the following is steam dial?
A. Non-coking bituminous coal
B. Brown coal
C. Pulverised coal
D. Coking bituminous coal
Answer : A

6. If a steam sample is nearly in dry condition, then its dryness fraction can be most accurately determined by
A. Throttling calorimeter
B. Separating calorimeter
C. Combined separating and throttling calorimeter
D. Bucket calorimeter
Answer : A

7. The number of water level indicators in a boiler are generally _________ in number.
A. One
B. Two
C. Three
D. Four
Answer : B

8. 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

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

10. 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

11. In an impulse turbine
A. The steam is expanded in nozzles only and there is a pressure drop and heat drop
B. The steam is expanded both in fixed and moving blades continuously
C. The steam is expanded in moving blades only
D. The pressure and temperature of steam remains constant
Answer : A

12. 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

13. The isentropic enthalpy drop in moving blade is two-third of the isentropic enthalpy drop in fixed blades of a turbine. The degree of reaction will be
A. 0.4
B. 0.56
C. 0.67
D. 1.67
Answer : A

14. Natural water circulation, by convection in water tube boilers, with increase in pressure of boiler
A. Increases
B. Decreases
C. Remain unaffected
D. First increases and then decreases
Answer : B

15. 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

16. 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

17. 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

18. The major axis of elliptical manholes on the shell should be provided
A. Longitudinally
B. Circumferentially
C. On dished end
D. Anywhere
Answer : B

19. The maximum discharge of steam through a convergent-divergent nozzle depends upon
A. Area of nozzle at throat
B. Initial pressure and volume of steam
C. Final pressure of steam leaving the nozzle
D. Both (A) and (B)
Answer : D

20. The pressure of reheat steam after passing through reheater compared to inlet condition is
A. More
B. Less
C. Equal
D. May be more or less depending on capacity of reheater
Answer : B

21. The density of supersaturated steam is about __________ that of the ordinary saturated vapour at the corresponding pressure.
A. Same as
B. 2 times
C. 4 times
D. 8 times
Answer : D

22. 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

23. The value of the reheat factor varies from
A. 1.02 to 1.06
B. 1.08 to 1.10
C. 1.2 to 1.6
D. 1.6 to 2
Answer : A

24. 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

25. Besides mean effective pressure, the data required to determine the indicated power of an engine include
A. Piston diameter, length of stroke and calorific value of fuel
B. Piston diameter, specific fuel consumption and Calorific value of fuel
C. Piston diameter, length of stroke and speed of rotation
D. Specific fuel consumption, speed of rotation and torque
Answer : C

26. 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

27. 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

28. The theoretical indicator diagram of a simple steam engine is based upon the assumption that
A. There is no pressure drop due to condensation
B. Steam is admitted at boiler pressure and exhausted at condenser pressure
C. The expansion (or compression) of the steam is hyperbolic
D. All of the above
Answer : D

29. 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

30. A vessel into which the steam is exhausted and condensed after doing work in an engine cylinder or turbine is known as
A. Steam condenser
B. Steam boiler
C. Steam preheater
D. Economiser
Answer : A

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

32. 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

33. The water tubes in a Babcock and Wilcox boiler are
A. Horizontal
B. Vertical
C. Inclined
D. Horizontal and inclined
Answer : C

34. The action of steam in a steam turbine is
A. Static
B. Dynamic
C. Static and dynamic
D. Neither static nor dynamic
Answer : B

35. The difference between Cornish boiler and Lancashire boiler is that
A. Former is fire tube type and latter is water tube type boiler
B. Former is water tube type and latter is fire tube type
C. Former contains one fire tube and latter contains two fire tubes
D. None/of the above
Answer : C

36. The diameter of flue tube in a Cornish boiler is _________ that of the shell.
A. One-fourth
B. One-third
C. Two-fifth
D. Three-fifth
Answer : D

37. 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

38. Which of the following statement is wrong?
A. The critical pressure gives the velocity of steam at the throat equal to the velocity of sound.
B. The flow in the convergent portion of the nozzle is subsonic.
C. The flow in the divergent portion of the nozzle is supersonic.
D. To increase the velocity of steam above sonic velocity (supersonic) by expanding steam below the critical pressure, the divergent portion for the nozzle is not necessary.
Answer : D

39. 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

40. 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

41. Which type of boiler can meet rapid changes of load?
A. Vertical fire tube type
B. Horizontal fire tube type
C. Horizontal water tube type
D. Forced circulation type
Answer : D

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

43. Which of the following are boiler accessories?
A. Economiser
B. Superheater
C. Both (A) and (B)
D. None of these
Answer : C

44. The length of Cornish boiler varies from
A. 2 to 4.5 m
B. 3 to 5 m
C. 5 to 7.5 m
D. 7 to 9 m
Answer : C

45. 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

46. 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

47. 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

48. Boiler H.P. is defined as the
A. Steam evaporation rate per kg of fuel fired
B. Work done in evaporating 1 kg of steam per hour from and at 100°C into dry saturated steam
C. The evaporation of 15.65 kg of water per hour from and at 100°C into dry saturated steam
D. Work done by 1 kg of steam at saturation condition
Answer : C

49. Lancashire boiler is
A. Stationary fire tube boiler
B. Internally fired boiler
C. Horizontal boiler
D. All of these
Answer : D

50. In a reaction turbine
A. The steam is allowed to expand in the nozzle, where it gives a high velocity before it enters the moving blades
B. The expansion of steam takes place partly in the fixed blades and partly in the moving blades
C. The steam is expanded from a high pressure to a condenser pressure in one or more nozzles
D. The pressure and temperature of steam remains constant
Answer : B