Practice Test: Question Set - 19
1. The economiser is used in boilers to
- (A) Increase thermal
efficiency of boiler
- (B) Economize on fuel
- (C) Extract heat from the
exhaust flue gases
- (D) Increase flue gas
temperature
2. The reheat factor is the ratio of the
- (A) Cumulative
heat drop to the isentropic heat drop
- (B) Isentropic
heat drop to the heat supplied
- (C) Total
useful heat drop to the total isentropic heat drop
- (D) None
of the above
3. Which of the following statement is correct?
- (A) A
fire tube boiler occupies less space than a water tube boiler, for a given
power
- (B) Steam
at a high pressure and in large quantities can be produced with a simple
vertical boiler
- (C) A
simple vertical boiler has one fire tube
- (D) All
of the above
4. The three "Ts" for good combustion are
- (A) Temperature, time,
and turbulence
- (B) Total air, true fuel,
and turbulence
- (C) Thorough mixing,
total air and temperature
- (D) Total air, time, and
temperature
5. The value of the reheat factor varies from
- (A) 1.02 to 1.06
- (B) 1.08 to 1.10
- (C) 1.2 to 1.6
- (D) 1.6 to 2
6. Cut-off governing of steam engines is a method of controlling the engine output by varying
- (A) Volume
of intake steam
- (B) Pressure
of intake steam
- (C) Temperature
of intake steam
- (D) All
of these
7. The size of a boiler drum in pulverized fuel fired boiler, as its size and capacity, (steam pressure and flow ratings) increase
- (A) Increases
- (B) Decreases
- (C) Remains unchanged
- (D) Increases/decreases
depending on steam temperature requirements
8. A nozzle is said to be a divergent nozzle
- (A) When the
cross-section of the nozzle increases continuously from entrance to exit
- (B) When
the cross-section of the nozzle decreases continuously from entrance to exit
- (C) When the
cross-section of the nozzle first decreases from entrance to throat and then
increases from its throat to exit
- (D) None of the
above
9. The theoretical indicator diagram of a simple steam engine is based upon the assumption that
- (A) There
is no pressure drop due to condensation
- (B) Steam
is admitted at boiler pressure and exhausted at condenser pressure
- (C) The
expansion (or compression) of the steam is hyperbolic
- (D) All
of the above
10. If partial pressure of air and steam be ‘pa’ and ‘ps’ respectively in a condenser, then according to Dalton's law, the pressure in condenser is equal to
- (A) ps - pa
- (B) pa - ps
- (C) pa + ps
- (D) None of these
11. In turbines, the fluid undergoes a continuous steady flow process and the speed of flow is
- (A) Low
- (B) Very
low
- (C) High
- (D) Very
high
12. 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
13. On Mollier chart, free expansion, or throttling process from high pressure to atmosphere is represented by
- (A) Horizontal straight
line
- (B) Vertical straight
line
- (C) Straight inclined
line
- (D) Curved line
14. 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
15. The high pressure and low pressure cylinders in a Woolf type compound engine are regarded as having cranks
- (A) 180°
to each other
- (B) 90°
to each other
- (C) 0° to each
other
- (D) None
of these