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

1. 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

2. 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

3. When the circulation of water, in a boiler, is by a centrifugal pump, then the boiler is known as
A. Internally fired boiler
B. Externally fired boiler
C. Natural circulation boiler
D. Forced circulation boiler
Answer : D

4. Thermal efficiency of well maintained boiler will be of the order
A. 40 %
B. 50 %
C. 75 %
D. 90 %
Answer : D

5. Which of the following gases has the highest calorific value?
A. Producer gas
B. Coal gas
C. Water gas
D. Blast furnace gas
Answer : B

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

7. 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

8. Locomotive boiler is of the following type
A. Multi tubular
B. Horizontal
C. Internally fired
D. All of the above
Answer : D

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. 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

11. When the total heat of steam is h kJ/kg and the sensible heat of feed water is h_f1 kJ/kg, then the factor of evaporation is given by
A. (h - h_f1)/2257
B. (h + h_f1)/2257
C. (h × h_f1)/2257
D. None of these
Answer : A

12. Parson's reaction turbine is a __________ reaction turbine.
A. 40 percent
B. 50 percent
C. 60 percent
D. 70 percent
Answer : B

13. Green coal, in order to be burnt, must be
A. Heated sufficiently
B. Burnt in excess air
C. Heated to its ignition point
D. Burnt as powder
Answer : C

14. Which of the following is a water tube boiler?
A. Locomotive boiler
B. Cochran boiler
C. Cornish boiler
D. Babcock and Wilcox boiler
Answer : D

15. 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

16. 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

17. A device used to heat feed water by utilising the heat in me exhaust flue gases before leaving through the chimney, is known as
A. Economiser
B. Fusible plug
C. Superheater
D. Stop valve
Answer : A

18. A nozzle is said to be a divergent 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 : A

19. 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

20. 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

21. 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

22. 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

23. 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

24. 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

25. The velocity of steam leaving the nozzle (V) is given by (where K = Nozzle coefficient or nozzle efficiency, and h_d = Enthalpy or heat drop during expansion of steam in a nozzle)
A. V = 44.72 h_d K
B. V = 44.72 K h_d
C. V = 44.72 K h_d
D. V = 44.72 K h_d
Answer : C

26. Benson boiler requires
A. No drum
B. One drum
C. Two drums
D. Three drums
Answer : A

27. The high pressure boiler is one, which produces steam at a pressure more than
A. Atmospheric pressure
B. 5 kg/cm²
C. 10 kg/cm²
D. 7580 kg/cm²
Answer : D

28. Which of the following statement is correct?
A. A fire tube boiler occupies less space than a water tube boiler, for a given power.
B. Steam at a high pressure and in large quantities can be produced with a simple vertical boiler.
C. A simple vertical boiler has one fire tube.
D. All of the above
Answer : C

29. Relative percentage of heat absorbed through the heat transfer of (i) Furnace water wall (ii) Boiler tank (iii) Superheater (iv) Economiser (v) Air-heater of a typical boiler of 200 MW capacity would be of the order of
A. 48 : 20 : 15 : 7 : 10
B. 10 : 7 : 15 : 20 : 48
C. 20 : 48 : 7 : 15 : 10
D. 7 : 15 : 20 : 10 : 48
Answer : A

30. The specific heat of superheated steam in kcal/kg is generally of the order of
A. 0.1
B. 0.3
C. 0.5
D. 0.8
Answer : C

31. The best suited coal for chain or travelling grate stoker boiler is
A. Coking coal
B. Non-coking or free burning coal
C. Pulverised coal
D. High sulphur coal
Answer : B

32. Rateau turbine is
A. Simple reaction turbine
B. Velocity compounded turbine
C. Pressure compounded turbine
D. Pressure-velocity compounded turbine
Answer : C

33. 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

34. 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

35. 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

36. O? content in atmospheric air on weight basis is
A. 21 %
B. 23 %
C. 30 %
D. 40 %
Answer : B

37. When the cross-section of a nozzle __________ continuously from entrance to exit, it is called a convergent nozzle.
A. Increases
B. Decreases
C. Remain same
D. None of these
Answer : B

38. The flow of steam is supersonic
A. At the entrance to the nozzle
B. At the throat of the nozzle
C. In the convergent portion of the nozzle
D. In the divergent portion of the nozzle
Answer : D

39. The nozzle efficiency is the ratio of
A. Workdone on the blades to the energy supplied to the blades
B. Workdone on the blades per kg of steam to the total energy supplied per stage per kg of steam
C. Energy supplied to the blades per kg of steam to the total energy supplied per stage per kg of steam
D. None of the above
Answer : C

40. The balanced draft furnace is one using
A. Induced draft fan and chimney
B. Induced draft fan and forced draft fan
C. Forced draft fan and chimney
D. Any one of the above
Answer : B

41. Pulverised fuel is used for
A. Better burning
B. More calorific value
C. Less radiation loss
D. Medium sized units
Answer : A

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

43. 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

44. An economiser is installed in a boiler primarily to
A. Superheat the steam
B. Reduce fuel consumption
C. Increase steam pressure
D. All of these
Answer : B

45. In fire 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 : B

46. 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

47. 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

48. Water and sediment in fuel oil can be removed by
A. Heating the oil in the settling tanks
B. Cooling the oil in the settling tanks
C. Burning the oil
D. Suspension
Answer : A

49. 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

50. 1 kg.m is equal to
A. 9.81 Joules
B. 102 Joules
C. 427 Joules
D. None of these
Answer : A