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