Multiple Choice Questions on Steam Boilers and Nozzles - Set 14 - ObjectiveBooks

# Practice Test: Question Set - 14

1. One kg of steam sample contains 0.8 kg dry steam; Its dryness fraction is
(A) 0.2
(B) 0.8
(C) 1.0
(D) 0.6

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

3. The power of a boiler may be defined as
(A) The ratio of heat actually used in producing the steam to the heat liberated in the furnace
(B) The amount of water evaporated or steam produced in kg per kg of fuel burnt
(C) The amount of water evaporated from and at 100° C into dry and saturated steam
(D) The evaporation of 15.653 kg of water per hour from and at 100° C

4. Heating wet steam at constant temperature is heating it at constant
(A) Volume
(B) Pressure
(C) Entropy
(D) Enthalpy

5. The supersaturated flow of steam through a nozzle as compared to a stable flow, the available heat drop
(A) Remains the same
(B) Increases
(C) Decreases
(D) Is unpredictable

6. The velocity of flue gases (V) through the chimney under a static draught of (H') metres is given by
(A) V = 2g H'
(B) V = 2g/H'
(C) V = H'/2g
(D) V = 2gH'

7. Efficiency of a thermal cycle increases by
(A) Regeneration
(B) Reheating of steam
(C) Both (A) and (B)
(D) Cooling of steam

8. Parson's turbine is a
(A) Simple impulse turbine
(B) Simple reaction turbine
(C) Impulse-reaction turbine
(D) None of these

9. The diameter of a cylindrical shell of a Scotch marine boiler varies from
(A) 1.5 to 2 m
(B) 2.5 to 3.5 m
(C) 3.5 to 4.5 m
(D) None of these

10. The crown of the fire box is made hemispherical in order to
(A) Give maximum space
(B) Give maximum strength
(C) Withstand pressure inside boiler
(D) Resist intense heat in fire box

11. 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

12. 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

13. 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

14. Which of the following varieties of coals is mostly used in steam boilers?
(A) Non-coking bituminous coal
(B) Brown coal
(C) Peat
(D) None of the above

15. The compounding of turbines is done in order to
(A) Reduce speed of rotor
(B) Improve efficiency
(C) Reduce exit losses
(D) All of these

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