NDA - Steam Boilers, Engines, Nozzles & Turbines 1000+ MCQ [Solved] PDF Download
Thursday 9th of March 2023
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1. The average value of diagram factor lies between
A. 0.2 to 0.5
B. 0.5 to 0.65
C. 0.65 to 0.9
D. 0.8 to 1.2
Answer : C
A. 0.2 to 0.5
B. 0.5 to 0.65
C. 0.65 to 0.9
D. 0.8 to 1.2
Answer : C
2. When the speed of the engine is controlled by means of a valve in a steam pipe, which regulates the pressure of steam entering the engine, then the governing is known as
A. Throttle governing
B. Cut-off governing
C. By-pass governing
D. None of these
Answer : A
A. Throttle governing
B. Cut-off governing
C. By-pass governing
D. None of these
Answer : A
3. 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
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
4. 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
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
5. 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
A. In the drum
B. In the fire tubes
C. Above steam dome
D. Over the combustion chamber
Answer : D
6. 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
A. Equal to Carnot cycle
B. Less than Carnot cycle
C. More than Carnot cycle
D. Could be anything
Answer : B
7. 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
A. Degree of super-saturation
B. Degree of superheat
C. Degree of under-cooling
D. None of these
Answer : C
8. The efficiency of reaction turbine is maximum when (where ? = Angle made by the absolute velocity V at inlet)
A. Vb = 0.5 V cos?
B. Vb = V cos ?
C. Vb = 0.5 V² cos?
D. Vb = V² cos?
Answer : B
A. Vb = 0.5 V cos?
B. Vb = V cos ?
C. Vb = 0.5 V² cos?
D. Vb = V² cos?
Answer : B
9. 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
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
10. In a reaction turbine, when steam flows through the fixed blades,
A. Pressure increases while velocity decreases
B. Pressure decreases while velocity increases
C. Pressure and velocity both decreases
D. Pressure and velocity both increases
Answer : B
A. Pressure increases while velocity decreases
B. Pressure decreases while velocity increases
C. Pressure and velocity both decreases
D. Pressure and velocity both increases
Answer : B
11. One kilowatt-hour energy is equivalent to
A. 1000 J
B. 360 kJ
C. 3600 kJ
D. 3600 kW/sec
Answer : C
A. 1000 J
B. 360 kJ
C. 3600 kJ
D. 3600 kW/sec
Answer : C
12. The diameter of Cornish boiler varies from
A. 0.5 to 1 m
B. 1 to 2 m
C. 1.25 to 2.5 m
D. 2 to 3 m
Answer : B
A. 0.5 to 1 m
B. 1 to 2 m
C. 1.25 to 2.5 m
D. 2 to 3 m
Answer : B
13. Vacuum for reciprocating steam engines compared to steam turbines is
A. More
B. Equal
C. Less
D. Could be more or less depending on the size of plant
Answer : C
A. More
B. Equal
C. Less
D. Could be more or less depending on the size of plant
Answer : C
14. Which of the following statement is wrong?
A. The mechanical draught reduces the height of chimney.
B. The natural draught reduces the fuel consumption.
C. A balanced draught is a combination of induced and forced draught.
D. All of the above
Answer : B
A. The mechanical draught reduces the height of chimney.
B. The natural draught reduces the fuel consumption.
C. A balanced draught is a combination of induced and forced draught.
D. All of the above
Answer : B
15. Thermal efficiency of a thermal power plant is of the order of
A. 15 %
B. 20 %
C. 30 %
D. 45 %
Answer : C
A. 15 %
B. 20 %
C. 30 %
D. 45 %
Answer : C
16. 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
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
17. In locomotives, the draught is produced by
A. Chimney
B. Induced draft fan
C. Both combined (A) and (B)
D. Steam jet draught
Answer : D
A. Chimney
B. Induced draft fan
C. Both combined (A) and (B)
D. Steam jet draught
Answer : D
18. In order to obtain superheated steam, a superheater is added in an existing boiler. As as result, furnace vacuum will
A. Remain unaffected
B. Improve
C. Worsen
D. May improve/worsen depending on size
Answer : C
A. Remain unaffected
B. Improve
C. Worsen
D. May improve/worsen depending on size
Answer : C
19. 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
A. Water
B. Dry steam
C. Wet steam
D. Super heated steam
Answer : D
20. Willians line for the steam engine is a straight line relationship between the steam consumption per hour and
A. Indicated power
B. Brake power
C. Efficiency
D. Pressure of steam
Answer : A
A. Indicated power
B. Brake power
C. Efficiency
D. Pressure of steam
Answer : A
21. The turbine blades are
A. Straight
B. Circular
C. Curved
D. None of these
Answer : C
A. Straight
B. Circular
C. Curved
D. None of these
Answer : C
23. In locomotive boiler, maximum steam pressure is limited to
A. 1 kg/cm²
B. 5 kg/cm²
C. 10 kg/cm²
D. 18 kg/cm²
Answer : D
A. 1 kg/cm²
B. 5 kg/cm²
C. 10 kg/cm²
D. 18 kg/cm²
Answer : D
24. In accelerated 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 : B
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 : B
25. 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
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
26. Fire tube boilers are
A. Internally fired
B. Externally fired
C. Internally as well as externally fired
D. None of these
Answer : A
A. Internally fired
B. Externally fired
C. Internally as well as externally fired
D. None of these
Answer : A
27. The basic purpose of drum in boiler is to
A. Serve as storage of steam
B. Serve as storage of feed water for water wall
C. Remove salts from water
D. Separate steam from water
Answer : D
A. Serve as storage of steam
B. Serve as storage of feed water for water wall
C. Remove salts from water
D. Separate steam from water
Answer : D
28. The diagram 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 : A
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 : A
29. 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
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
30. During polytropic process
A. Heat transfer takes place across cylinder walls
B. Work is done
C. Steam may be wet, dry or superheated after expansion
D. All of the above
Answer : D
A. Heat transfer takes place across cylinder walls
B. Work is done
C. Steam may be wet, dry or superheated after expansion
D. All of the above
Answer : D
31. 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
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
32. Gusset stays in a boiler are provided to
A. Prevent the bulging of flat surfaces
B. Avoid explosion in furnace
C. Prevent leakage of hot flue gases
D. Support furnace freely from top
Answer : A
A. Prevent the bulging of flat surfaces
B. Avoid explosion in furnace
C. Prevent leakage of hot flue gases
D. Support furnace freely from top
Answer : A
33. The average operating pressure of Benson boiler is
A. 100 bar
B. 150 bar
C. 200 bar
D. 250 bar
Answer : D
A. 100 bar
B. 150 bar
C. 200 bar
D. 250 bar
Answer : D
34. The overall efficiency of thermal power plant is
A. Boiler efficiency, turbine efficiency, generator efficiency
B. All the three above plus gas cycle efficiency
C. Carnot cycle efficiency
D. Regenerative cycle efficiency
Answer : A
A. Boiler efficiency, turbine efficiency, generator efficiency
B. All the three above plus gas cycle efficiency
C. Carnot cycle efficiency
D. Regenerative cycle efficiency
Answer : A
35. The fire tubes in a Scotch marine boiler are
A. Horizontal
B. Vertical
C. Inclined
D. None of these
Answer : A
A. Horizontal
B. Vertical
C. Inclined
D. None of these
Answer : A
36. In regenerative 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 gas from furnace
Answer : B
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 gas from furnace
Answer : B
37. When the back pressure of a nozzle is below the designed value of pressure at exit of nozzle, the nozzle is said to be
A. Choked
B. Under-damping
C. Over-damping
D. None of these
Answer : B
A. Choked
B. Under-damping
C. Over-damping
D. None of these
Answer : B
38. 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
A. 30 MW
B. 60 MW
C. 100 MW
D. 500 MW
Answer : D
39. Incomplete combustion can be best judged by
A. Smoky chimney exit
B. Excess air in flue gases
C. Measuring carbon monoxide in flue gases
D. Measuring temperature of flue gases at exit of furnace
Answer : C
A. Smoky chimney exit
B. Excess air in flue gases
C. Measuring carbon monoxide in flue gases
D. Measuring temperature of flue gases at exit of furnace
Answer : C
40. Multi-stage steam turbines are of the
A. Velocity compounded type
B. Reaction type
C. Pressure compounded type
D. All of these
Answer : D
A. Velocity compounded type
B. Reaction type
C. Pressure compounded type
D. All of these
Answer : D
41. In cross compounding, the cylinders are arranged
A. Side by side and each cylinder has common piston, connecting rod and crank
B. Side by side and each cylinder has separate piston, connecting rod and crank
C. At 90° and each cylinder has common piston, connecting rod and crank
D. At 90° and each cylinder has separate piston, connecting rod and crank
Answer : B
A. Side by side and each cylinder has common piston, connecting rod and crank
B. Side by side and each cylinder has separate piston, connecting rod and crank
C. At 90° and each cylinder has common piston, connecting rod and crank
D. At 90° and each cylinder has separate piston, connecting rod and crank
Answer : B
42. Hygrometry deals with the
A. Hygroscopic substances
B. Water vapour in air
C. Temperature of air
D. Pressure of air
Answer : B
A. Hygroscopic substances
B. Water vapour in air
C. Temperature of air
D. Pressure of air
Answer : B
43. The rate of steam produced in Benson boiler is
A. 100 tonnes/h
B. 135 tonnes/h
C. 175 tonnes/h
D. 250 tonnes/h
Answer : B
A. 100 tonnes/h
B. 135 tonnes/h
C. 175 tonnes/h
D. 250 tonnes/h
Answer : B
44. The friction present between the steam and the nozzle surfaces reduces the heat drop by
A. 10 to 15 %
B. 15 to 25 %
C. 25 to 40 %
D. 40 to 60 %
Answer : A
A. 10 to 15 %
B. 15 to 25 %
C. 25 to 40 %
D. 40 to 60 %
Answer : A
45. Benson boiler requires
A. No drum
B. One drum
C. Two drums
D. Three drums
Answer : A
A. No drum
B. One drum
C. Two drums
D. Three drums
Answer : A
46. Secondary 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 induced draft fan
Answer : A
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 induced draft fan
Answer : A
47. All steam engines work on
A. Zeroth law of thermodynamics
B. First law of thermodynamics
C. Second law of thermodynamics
D. None of these
Answer : C
A. Zeroth law of thermodynamics
B. First law of thermodynamics
C. Second law of thermodynamics
D. None of these
Answer : C
48. In a throttling process
A. Heat transfer takes place
B. Work is done by the expanding steam
C. Internal energy of steam changes
D. None of the above
Answer : D
A. Heat transfer takes place
B. Work is done by the expanding steam
C. Internal energy of steam changes
D. None of the above
Answer : D
49. Lancashire boiler is used where working pressure and power required are
A. Low
B. Moderate
C. High
D. None of these
Answer : B
A. Low
B. Moderate
C. High
D. None of these
Answer : B
50. 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
A. Efficiency of the boiler
B. Efficiency of the chimney
C. Efficiency of the fan
D. Power of the boiler
Answer : B
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