1000+ Steam Boilers, Engines, Nozzles & Turbines MCQ for RBI Grade B officer [Solved]

1. 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

2. The length of Cornish boiler is of the order of
A. 24 m
B. 35 m
C. 57.5 m
D. 79 m
Answer : C

3. In order to reduce the rotor speed of an impulse turbine, the method employed is
A. Velocity compounding
B. Pressure compounding
C. Pressure-velocity compounding
D. All of these
Answer : D

4. During storage, the heating value of coal
A. Increases
B. Decreases
C. Remain constant
D. May increase or decrease depending upon the method of storage
Answer : B

5. Maximum energy loss in a boiler occurs due to
A. Unburnt carbon in ash
B. Incomplete combustion
C. Ash content
D. Flue gases
Answer : D

6. A device used to put off fire in the furnace of the boiler when the level of water in the boiler falls to an unsafe limit, is called
A. Blow off cock
B. Stop valve
C. Superheater
D. None of these
Answer : D

7. The heat loss in a boiler takes place in the form of
A. Heat carried away by flue gases
B. Heat carried away by ash
C. Moisture present in fuel and steam formed by combustion of hydrogen in fuel
D. All of the above
Answer : D

8. Water boils when its vapour pressure
A. Equals that of the surroundings
B. Equals 760 mm of mercury
C. Equals to atmospheric pressure
D. Equals the pressure of water in the container
Answer : A

9. 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

10. 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

11. The diagram factor is the ratio of the
A. Area of the actual indicator diagram to the area of theoretical indicator diagram
B. Actual workdone per stroke to the theoretical workdone per stroke
C. Actual mean effective pressure to the theoretical mean effective pressure
D. Any one of the above
Answer : D

12. Willian's law states that the steam consumption per hour provided with a throttled governor is proportional to (where I.P. = Indicated power)
A. 1/(I.P)
B. 1/(I.P)²
C. I.P.
D. (I.P.)²
Answer : C

13. 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

14. The principal function of a stop valve is to
A. Control the flow of steam from the boiler to the main pipe and to shut off the steam completely when required
B. Empty the boiler when required and to discharge the mud, scale or sediments which are accumulated at the bottom of the boiler
C. Put off fire in the furnace of the boiler when the level of water in the boiler falls to an unsafe limit
D. Increase the temperature of saturated steam without raising its pressure
Answer : A

15. Pick up the wrong statement about water tube boiler in comparison to fire tube boilers
A. Former occupies less space for same power
B. Rate of steam flow is more in former case
C. Former is used for high installed capacity
D. Chances of explosion are less in former case.
Answer : D

16. The critical pressure gives the velocity of steam at the throat
A. Equal to the velocity of sound
B. Less than the velocity of sound
C. More than the velocity of sound
D. None of these
Answer : A

17. In a De-Laval nozzle expanding superheated steam from 10 bar to 0.1 bar, the pressure at the minimum cross-section (i. e. pressure at throat, p?) will be
A. 3.3 bar
B. 5.46 bar
C. 8.2 bar
D. 9.9 bar
Answer : B

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

19. 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

20. De-Laval turbine is a
A. Simple impulse turbine
B. Simple reaction turbine
C. Impulse-reaction turbine
D. None of these
Answer : A

21. The velocity of whirl at outlet for an axial discharge turbine is
A. Minimum
B. Maximum
C. Zero
D. None of these
Answer : C

22. The function of a flywheel is
A. To convert reciprocating motion of the piston into rotary motion
B. To convert rotary motion of the crankshaft into to and fro motion of the valve rod
C. To prevent fluctuation of speed
D. To keep the engine speed uniform at all load conditions
Answer : C

23. When the circulation of water, in a boiler, is by convection currents which are set up during the heating of water, then the boiler is known as
A. Internally fired boiler
B. Externally fired boiler
C. Natural circulation boiler
D. Forced circulation boiler
Answer : C

24. The maximum steam pressure in a Locomotive boiler is limited to
A. 0.18 MN/m²
B. 1.8 MN/m²
C. 18 MN/m²
D. 180 MN/m²
Answer : B

25. In a Parson's turbine stage, blade velocity is 320 m/s at the mean radius and rotor blade exit angle is 30°. For minimum kinetic energy of the steam leaving the stage, the steam velocity at the exit of the rotor will be
A. 160/3 m/s
B. 320/3 m/s
C. 640/3 m/s
D. 640 m/s
Answer : C

26. 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

27. Thermal equilibrium means that the flow of steam is
A. Isothermal
B. Isentropic
C. Hyperbolic
D. Polytropic
Answer : B

28. Which of the following statement is wrong?
A. Locomotive boiler is a water tube boiler
B. Water tube boilers are internally fired
C. Lamont boiler is a low pressure water tube boiler
D. All of the above
Answer : D

29. 100% efficiency of a thermal cycle cannot be achieved because of
A. Frictional losses
B. It is not possible to achieve 0°K temperature
C. Leakage
D. Non availability of ideal substance
Answer : B

30. 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

31. Which of the following statement is wrong?
A. The factor of evaporation for all boilers is always greater than unity.
B. The amount of water evaporated in kg per kg of fuel burnt is called equivalent evaporation from and at 100° C.
C. The ratio of heat actually used in producing the steam to the heat liberated in the furnace is called boiler efficiency.
D. None of the above
Answer : D

32. Lancashire boiler is of
A. Stationary < fire tube type
B. Horizontal type
C. Natural circulation type
D. All of the above
Answer : D

33. A throttle governed steam engine develops 15 kW with 280 kg per hour of steam and 35 kW with 520 kg per hour of steam. The steam consumption in kg per hour when developing 20 kW will be nearly
A. 150 kg/h
B. 210 kg/h
C. 280 kg/h
D. 340 kg/h
Answer : D

34. 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

35. Primary 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 forced draft fan
Answer : B

36. 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

37. Fire 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. Forced circulation takes place
D. Tubes are laid vertically
Answer : A

38. De-Laval turbine is a
A. Single rotor impulse turbine
B. Multi-rotor impulse turbine
C. Impulse reaction turbine
D. None of these
Answer : A

39. 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

40. 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

41. 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

42. If partial pressure of air and steam be p_a and p_s respectively in a condenser, then according to Dalton's law, the pressure in condenser is equal to
A. p_s - p_a
B. p_a - p_s
C. p_a + p_s
D. None of these
Answer : C

43. 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

44. Feed water conditioning in thermal power plants in done to
A. Reduce hardness and for removal of solids
B. Increase efficiency of thermal power plant
C. Increase heat transfer rate
D. Increase steam parameters
Answer : A

45. 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

46. Cut-off governing as compared to throttle governing is
A. Less efficient and less economical
B. Less efficient and more economical
C. More efficient and less economical
D. More efficient and more economical
Answer : D

47. The average operating pressure of Benson boiler is
A. 100 bar
B. 150 bar
C. 200 bar
D. 250 bar
Answer : D

48. In a velocity compounded impulse turbine, when steam flows through the second row of moving blades,
A. Velocity increases
B. Velocity decreases
C. Velocity remains constant
D. Pressure remains constant
Answer : B

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