Engineering Thermodynamics MCQ

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Engineering Thermodynamics MCQ

Engineering Thermodynamics MCQ, Engineering Thermodynamics Multiple Choice Questions, Thermodynamics MCQ, Multiple Choice Questions on Engineering Thermodynamics, Basic Mechanical Engineering MCQ, Engineering MCQ, BMC MCQ,

Objective Type Questions

Q.1. During sensible heating of moist air, enthalpy

  • increases
  • decreases
  • remains constant
  • none of the above.

Answer: increases

Q.2. In an unsaturated air the state of a vapour is

  • wet
  • superheated
  • saturated
  • unsaturated

Answer: superheated

Q.3. Triple point of a pure substance is a point at which

  • liquid and vapour exist together
  • solid and liquid exist together
  • solid and vapour exist together
  • solid, liquid and vapour exist together

Answer: solid, liquid and vapour exist together

Q.4. Triple point of a pure substance on p-V diagram is represented by a

  • point
  • line
  • curve
  • triangle

Answer: line

Q.5. A substance above critical temperature is

  • solid
  • liquid
  • gas
  • vapour
  • supersaturated fluid

Answer: supersaturated fluid

Q.6. The latent heat of vaporisation at critical point is

  • less than zero
  • greater than zero
  • equal to zero
  • none of the above

Answer: equal to zero

Q.7. With the increase in pressure

  • boiling point of water increases and enthalpy of evaporation increases
  • boiling point of water increases and enthalpy of evaporation increases
  • boiling point of water decreases and enthalpy of evaporation increases
  • none of the above

Answer: boiling point of water increases and enthalpy of evaporation increases

Q.8. With the increase in pressure

  • enthalpy of dry saturated steam increases
  • enthalpy of dry saturated steam decreases
  • enthalpy of dry saturated steam remains same
  • none of the above

Answer: enthalpy of dry saturated steam decreases

Q.9. Dryness fraction of steam is defined as

  • mass of water vapour in suspension/(mass of water vapour in suspension + mass of dry steam)
  • mass of dry steam/mass of water vapour in suspension
  • mass of dry steam/(mass of dry steam + mass of water vapour in suspension)
  • none of the above

Answer: mass of dry steam/(mass of dry steam + mass of water vapour in suspension)

Q.10. The specific volume of water when heated at 0°C

  • First increases and then decreases
  • First decreases and then increases
  • Increases steadily
  • Decreases steadily

Answer: First decreases and then increases

Q.11. Only throttling calorimeter is used for measuring

  • Very low dryness fraction upto 0.7
  • Very high dryness fraction upto 0.98
  • Dryness fraction of only low pressure steam
  • Dryness fraction of only high pressure steam

Answer: Very high dryness fraction upto 0.98

Q.12. The water tubes in a simple vertical boiler are 

  • horizontal
  • vertical
  • inclined
  • nothing

Answer: horizontal

Q.13. Lancashire boiler is a

  • stationary fire tube boiler
  • internally fired boiler
  • horizontal boiler
  • natural circulation boiler
  • All of the above

Answer: All of the above

Q.14. The diameter of internal flue tubes of a Lancashire boiler is about …… of its shell

  • 1/4
  • 1/3
  • 2/5
  • ½

Answer: 2/5

Q.15. Locomotive boiler is a

  • single tube, horizontal internally fired and stationary boiler
  • single tube, vertical externally fired and stationary boiler
  • Multitubular, horizontal internally fired and mobile boiler
  • Multitubular, horizontal externally fired and stationary boiler

Answer: Multitubular, horizontal internally fired and mobile boiler

Q.16. Which of the following is a water tube boiler?

  • Lancashire boiler
  • Babcock and Wilcox boiler
  • Locomotive boiler
  • Cochran boiler

Answer: Babcock and Wilcox boiler

Q.17. Water tube boilers produce steam at pressure than that of fire tube boilers

  • Lower
  • Higher
  • Equal
  • Can’t say

Answer: Higher

Q.18. The Locomotive boiler has

  • 137 fire tubes and 44 superheated tubes
  • 147 fire tubes and 34 superheated tubes
  • 157 fire tubes and 24 superheated tubes
  • 167 fire tubes and 14 superheated tubes

Answer: 157 fire tubes and 24 superheated tubes

Q.19. The air pressure at the fuel bed is reduced below that of atmosphere by means of a fan placed at or near the bottom of the chimney to produce a draught, such a draught is called

  • Natural draught
  • Induced
  • Forced draught
  • Balanced draught

Answer: Induced

Q.20. The draught may be produced by a

  • Mechanical fun
  • Chimney
  • Steam jet
  • All of these

Answer: All of these

Q.21. The draught in locomotive boilers is produced by a

  • Chimney
  • Centrifugal fan
  • Steam jet
  • None of these

Answer: Steam jet

Q.22. The draught produced by a steam jet issuing from a nozzle placed in the chimney is called

  • induced steam jet draught
  • forced steam jet draught
  • height of chimney
  • all of these

Answer: induced steam jet draught

Q.23. The chimney draught varies with

  • climatic conditions
  • temperature of furnace gases
  • height of chimney
  • all of these

Answer: all of these

Q.24. Which of the following statements is wrong?

  • The mechanical draught reduces the height of chimney
  • The natural draught reduces the fuel consumption
  • A balanced draught is a combination of induced and forced draught
  • all of the above
  • none of these

Answer: The natural draught reduces the fuel consumption

Q.25. The amount of water evaporated in kg/kg of fuel burnt is called

  • equivalent evaporation from and at 100°C
  • evaporative capacity of a boiler
  • boiler efficiency
  • none of the above

Answer: equivalent evaporation from and at 100°C

Q.26. The ratio of the heat actually used in producing the steam to the heat liberated in the furnace is called

  • equivalent evaporation from and at 100°C
  • evaporative capacity of boiler
  • boiler efficiency
  • none of the above

Answer: boiler efficiency

Q.27. A device attached to the steam chest for preventing explosions due to excessie internal pressure is called

  • Safety valve
  • Water level indicator
  • Pressure gauge
  • Fusible plug

Answer: Safety valve

Q.28. A safety valve mainly used with locomotive and marine boilers is

  • lever safety valve
  • high pressure valve
  • dead weight safety valve
  • spring loaded safety valve

Answer: spring loaded safety valve

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