1000+ Steam Boilers, Engines, Nozzles & Turbines MCQ for XAT [Solved]

1. Reheating of steam under ideal conditions takes place at constant
A. Entropy
B. Enthalpy
C. Pressure
D. Temperature
Answer : D

2. The high steam and low water safety valve is used to blow off steam when the
A. Steam pressure exceeds the working pressure
B. Water level in the boiler becomes too low
C. Both (A) and (B)
D. None of the above
Answer : C

3. 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

4. The cylinder condensation or missing quantity may be reduced by
A. The efficient steam jacketing of the cylinder walls
B. Superheating the steam supplied to the engine cylinder
C. Keeping the expansion ratio small in each cylinder
D. All of the above
Answer : D

5. 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

6. The diameter of fire tubes in Cochran boiler is of the order of
A. 2 cm
B. 6 cm
C. 8 cm
D. 12 cm
Answer : B

7. 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

8. The cylindrical shell of a Lancashire boiler has diameter from
A. 1 to 2 m
B. 1.25 to 2.25 m
C. 1.5 to 2.5 m
D. 1.75 to 2.75 m
Answer : D

9. Which of the following statement is correct?
A. The efficiency of steam turbines is greater than steam engines
B. A flywheel is a must for steam turbine
C. The turbine blades do not change the direction of steam issuing from the nozzle
D. The pressure of steam, in reaction turbines, is increased in fixed blades as well as in moving blades
Answer : A

10. Which of the following statement is correct for steam turbines as compared to reciprocating steam engines?
A. A steam turbine develops higher speeds
B. The efficiency of steam turbine is higher
C. The steam consumption is less
D. All of these
Answer : D

11. Steam turbines are used for
A. Large marine propulsion
B. Electric power generation
C. Direct drive of fans, compressors, pumps
D. All of these
Answer : D

12. Locomotive boiler is a
A. Single tube, horizontal, internally fired and stationary boiler
B. Single tube, vertical, externally fired and stationary boiler
C. Multi-tubular, horizontal, internally fired and mobile boiler
D. Multi-tubular, horizontal, externally fired and stationary boiler
Answer : C

13. Sulphur content of fuels is very important to the plant operators because it
A. Has high heating value
B. Retards electric precipitation
C. Promotes complete combustion
D. Has highly corrosive effect
Answer : D

14. 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

15. In a Tandem 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 : A

16. 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

17. In natural circulation type boiler,
A. Heating takes place at bottom and the water supplied at bottom gets converted into the mixture of steam bubbles and hot water which rise to drum
B. Water is supplied in drum and through down comers located in atmospheric condition it passes to the water wall and rises to drum in the form of mixture of water and steam
C. Feed pump is employed to supplement natural circulation in water wall type furnace
D. Water is converted into steam in one. Pass without any recirculation
Answer : A

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

19. Cut-off ratio is the ratio of
A. Swept volume to the volume at cut-off
B. Volume at cut-off to the clearance volume
C. Volume at cut-off to the swept volume
D. Clearance volume to the volume at cut-off
Answer : C

20. A single acting steam engine produces ________ power than that of double acting steam engine.
A. Equal
B. Half
C. Double
D. Four times
Answer : B

21. 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

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

23. 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

24. Which of the following boiler is best suited to meet the fluctuating demand of steam?
A. Locomotive boiler
B. Lancashire boiler
C. Cornish boiler
D. Babcock and Wilcox boiler
Answer : A

25. The function of injector used in small steam plants is to
A. Create vacuum in furnace
B. Create vacuum at turbine exhaust
C. Pump feed water
D. Dose chemicals in feed water
Answer : C

26. The shell of the Cochran boiler is made hemispherical
A. To give maximum space and strength
B. To withstand the pressure of steam inside the boiler
C. Both (A) and (B)
D. None of the above
Answer : C

27. The relative efficiency is defined as the
A. Ratio of thermal efficiency to 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 : A

28. 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

29. A steam turbine, in which a part of the steam after partial expansion, is used for process heating and the remaining steam is further expanded for power generation, is known as
A. Back pressure turbine
B. Pass out turbine
C. Low pressure turbine
D. Impulse turbine
Answer : B

30. The fire tubes in a Cochran boiler usually have _________ diameter.
A. 6.25 mm
B. 62.5 mm
C. 72.5 mm
D. 92.5 mm
Answer : B

31. The main object of a boiler trial is
A. To determine the generating capacity of the boiler
B. To determine the thermal efficiency of the boiler when working at a definite pressure
C. To prepare heat balance sheet for the boiler
D. All of the above
Answer : D

32. 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

33. Fire tube boilers are
A. Internally fired
B. Externally fired
C. Internally as well as externally fired
D. None of these
Answer : A

34. When the speed of the crankshaft is between 100 r.p.m. and 250 r.p.m., the engine said to be a
A. Slow speed engine
B. Medium speed steam engine
C. High speed steam engine
D. None of these
Answer : B

35. In designing air preheaters, the important design consideration is that
A. Approach temperature should be as low as possible
B. Handling and maintenance should be easier
C. Heat transfer area should be optimum
D. Stack gases should not be cooled to the dew point
Answer : D

36. 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

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. The process of maintaining the speed of the turbine constant for various load conditions, is known as
A. Bleeding
B. Reheating
C. Governing
D. None of these
Answer : C

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

40. 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

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

42. Equivalent evaporation of water is the evaporation for a feed water supply at 100°C
A. And its corresponding conversion into dry saturated steam at 100°C and 1.033 kg/cm²
B. And its corresponding conversion into dry steam at desired boiler pressure
C. Conversion into steam at atmospheric condition
D. Conversion into steam at the same pressure at which feed water is supplied
Answer : A

43. The efficiency of an impulse turbine is maximum when (where V_b = Blade speed, V = Absolute velocity of steam entering the blade, and ? = Nozzle angle)
A. V_b = 0.5 V cos?
B. V_b = V cos?
C. V_b = 0.5 V² cos?
D. V_b = V² cos?
Answer : A

44. The amount of water evaporated from feed water at _________ into dry and saturated steam at 100° C at normal atmospheric pressure is called equivalent evaporation from and at 100° C.
A. 0°C
B. 40°C
C. 60°C
D. 100°C
Answer : D

45. In a nozzle, the effect of super-saturation is to
A. Decrease dryness fraction of steam
B. Decrease specific volume of steam
C. Increase the entropy
D. Increase the heat drop
Answer : C

46. Multi-stage steam turbines are of the
A. Velocity compounded type
B. Reaction type
C. Pressure compounded type
D. All of these
Answer : D

47. An impulse turbine as compared to a reaction turbine, for a given power has _________ row of blades.
A. Equal
B. Less
C. More
D. None of these
Answer : C

48. 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

49. The ratio of the energy required to produce the artificial draught (expressed in metres head or J/kg of flue gas) to the mechanical equivalent of extra heat carried away per kg of flue gases due to natural draught, is known as
A. Efficiency of the boiler
B. Efficiency of the chimney
C. Efficiency of the fan
D. Power of the boiler
Answer : B

50. Reheating of steam in a turbine
A. Increases the workdone through the turbine
B. Increases the efficiency of the turbine
C. Reduces wear on the blades
D. All of these
Answer : D