Lakshya Education MCQs

Question: Blow off cock in a boiler is used 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: Option B

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More Questions on This Topic :

Question 1. The factor of evaporation for all boilers is always
  1.    Equal to unity
  2.    Less than unity
  3.    Greater than unity
  4.    None of these
Answer: Option C
Question 2. Film boiling occurs at
  1.    Very low pressure
  2.    Atmospheric pressures
  3.    Medium pressures
  4.    Very high pressures
Answer: Option D
Question 3. While steam expands in turbines, theoretically the entropy
  1.    Remains constant
  2.    Increases
  3.    Decreases
  4.    Behaves unpredictably
Answer: Option A
Question 4. The ratio of the workdone on the blades to the energy supplied to the blades, is called
  1.    Blading efficiency
  2.    Nozzle efficiency
  3.    Gross or stage efficiency
  4.    Mechanical efficiency
Answer: Option A
Question 5. Incomplete combustion can be best judged by
  1.    Smoky chimney exit
  2.    Excess air in flue gases
  3.    Measuring carbon monoxide in flue gases
  4.    Measuring temperature of flue gases at exit of furnace
Answer: Option C
Question 6. Green coal, in order to be burnt, must be
  1.    Heated sufficiently
  2.    Burnt in excess air
  3.    Heated to its ignition point
  4.    Burnt as powder
Answer: Option C

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