Steam Boilers, Engines, Nozzles & Turbines 1000+ MCQ with answer for IIFT

1. A condenser where circulating water flows through tubes which are surrounded by steam, in known as
A. Surface condenser
B. Jet condenser
C. Barometric condenser
D. Evaporative condenser
Answer : A

2. In water wall furnace, the heat is transferred to the water walls by
A. Convection
B. Radiation
C. Conduction
D. Radiation and conduction
Answer : B

3. The fire tubes in a Scotch marine boiler are
A. Horizontal
B. Vertical
C. Inclined
D. None of these
Answer : A

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. 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

6. The coal requirement per kW hour generation in the thermal power plant is of the order of
A. 0.1 to 0.2 kg
B. 0.2 to 0.4 kg
C. 0.6 to 0.8 kg
D. 1.0 to 1.5 kg
Answer : C

7. Latent heat of dry steam at atmospheric pressure is equal to
A. 539 kcal/ kg
B. 539 BTU/ lb
C. 427 kcal/ kg
D. 100 kcal/ kg
Answer : A

8. 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

9. 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

10. The indicated thermal efficiency is defined as the
A. Ratio of thermal efficiency to the Rankine efficiency
B. Ratio of brake power to the indicated power
C. Ratio of heat equivalent to indicated power to the energy supplied in steam
D. Product of thermal efficiency and Rankine efficiency
Answer : C

11. 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

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

13. The heat balance sheet for the boiler shows the
A. Complete account of heat supplied by 1 kg of dry fuel and the heat consumed
B. Moisture present in the fuel
C. Steam formed by combustion of hydrogen per kg of fuel
D. All of the above
Answer : A

14. 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

15. In forced circulation steam boilers, the force is applied
A. To draw water
B. To circulate water
C. To drain off the water
D. All of these
Answer : B

16. The diameters of fire tubes and superheater tubes in locomotive boiler are
A. 47.5 mm, 130 mm
B. 32.5 mm, 180 mm
C. 65.5 mm, 210 mm
D. 24.5 mm, 65 mm
Answer : A

17. The mechanical draught _________ with the amount of smoke.
A. Increases
B. Decreases
C. Does not effect
D. None of these
Answer : B

18. The diameter of tubes for natural circulation boiler as compared to controlled circulation boilers is
A. More
B. Less
C. Same
D. Could be more or less depending on other factors
Answer : A

19. The effect of bleeding is that
A. It increases the thermodynamic efficiency of the turbine
B. Boiler is supplied with hot water
C. It decreases the power developed by the turbine
D. All of the above
Answer : D

20. In order to compare the capacity of boilers, the feed water temperature and working pressure are taken as
A. 50°C and normal atmospheric pressure
B. 50°C and 1.1 bar pressure
C. 100°C and normal atmospheric pressure
D. 100°C and 1.1 bar pressure
Answer : C

21. If the critical pressure ratio for steam is 0.546, then the steam is initially
A. Wet steam
B. Dry saturated steam
C. Superheated steam
D. None of these
Answer : C

22. 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

23. Which of the following is correct? (Where p_a = Actual mean effective pressure, p_m = Theoretical mean effective pressure, and K = Diagram factor)
A. p_a = p_m/K
B. p_a = p_m × K
C. p_a = K/p_m
D. p_a = p_m + K
Answer : B

24. 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

25. The latent heat of steam with increase of pressure
A. Remain same
B. Increases
C. Decreases
D. Behaves unpredictably
Answer : C

26. 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

27. The radius of a dished head is taken approximately as
A. One fourth
B. Half
C. One
D. Two
Answer : C

28. The dry saturated steam at very low pressure, (510 kg/cm²) when throttled to atmosphere will become
A. Wet
B. Superheated
C. Remain dry saturated
D. Dry
Answer : B

29. The proximate analysis of fuel lists
A. Various chemical constituents, carbon, hydrogen, oxygen etc, plus ash as percents by volume
B. Various chemical constituents, carbon, hydrogen, oxygen, etc, plus ash as percents by weight
C. Fuel constituents as percents by volume of moisture, volatile, fixed carbon and ash
D. Fuel constituents as percents by weight of moisture, volatile, fixed carbon and ash
Answer : D

30. Fusible plug for boilers is made of fusible metal containing tin, lead, and
A. Bismuth
B. Copper
C. Aluminium
D. Nickel
Answer : A

31. 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

32. Which of the following is a fire tube boiler?
A. Lancashire boiler
B. Babcock and Wilcox boiler
C. Yarrow boiler
D. None of these
Answer : A

33. 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

34. The dry saturated steam at very high pressure (150200 kg/cm²) when throttled to atmosphere will become
A. Wet
B. Superheated
C. Remain dry saturated
D. Dry
Answer : A

35. A regenerative steam cycle renders
A. Increased work output per unit mass of steam
B. Decreased work output per unit mass of steam
C. Increased thermal efficiency
D. Decreased work output per unit mass of steam as well as increased thermal efficiency
Answer : D

36. A safety valve usually employed with stationary boilers is
A. Lever safety valve
B. Dead weight safety valve
C. High steam and low water safety valve
D. All of these
Answer : D

37. 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

38. The critical pressure ratio for initially superheated steam is __________ as compared to initially dry saturated steam.
A. More
B. Less
C. Same
D. None of these
Answer : B

39. 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

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

41. The pressure compounded impulse turbine as compared to velocity compounded turbine require __________ number of stages.
A. Same
B. Less
C. More
D. None of these
Answer : C

42. Which is not the correct statement about moisture in coal?
A. Inherent moisture and surface moisture are different things
B. In some coals moisture may be present up to 40%
C. Some moisture in coal helps in better burning which is not possible with completely dry coal
D. It increases thermal efficiency
Answer : D

43. The safety valve at superheater as compared to drum safety valve setting is set at
A. Higher value
B. Lower value
C. Same value
D. Any value
Answer : B

44. 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

45. A valve installed between the boiler and the feed pump is
A. Blow off cock
B. Feed check valve
C. Steam stop valve
D. None of these
Answer : B

46. In a boiler, the heat is lost
A. To dry flue gases
B. In moisture present in the fuel
C. To steam formed by combustion of hydrogen per kg of fuel
D. All of the above
Answer : D

47. 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

48. 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

49. For water, at pressures below atmospheric;
A. Melting point rises slightly and boiling point drops markedly
B. Melting point rises markedly and boiling point drops markedly
C. Melting point drops slightly and boiling point drops markedly
D. Melting point drops slightly and boiling point drops slightly
Answer : A

50. The biggest size of thermal power unit operating in India is
A. 30 MW
B. 60 MW
C. 100 MW
D. 500 MW
Answer : D