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Home Mechanical Engineering Heat Transfer, Refrigeration and Air Conditioning Comments

  • Question
  • In aircraft, air refrigeration Cycle is used because of


  • Options
  • A. low weight per tonne of refrigeration
  • B. high heat transfer rate
  • C. low temperature at high altitudes
  • D. higher coefficient of performance

  • Correct Answer
  • low weight per tonne of refrigeration 


  • Heat Transfer, Refrigeration and Air Conditioning problems


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    • 1. A refrigerant compressor is used to

    • Options
    • A. raise the pressure of the refrigerant
    • B. raise the temperature of the refrigerant
    • C. circulate the refrigerant through the refrigerating system
    • D. all of the above
    • Discuss
    • 2. In a vapour absorption refrigeration system, the compressor of the vapour compression system is replaced by

    • Options
    • A. liquid pump
    • B. generator
    • C. absorber and generator
    • D. absorber, generator and liquid pump
    • Discuss
    • 3. The refrigerant used in small-tonnage commercial machines (hermetically sealed units) is

    • Options
    • A. ammonia
    • B. carbon dioxide
    • C. sulphur dioxide
    • D. R-12
    • Discuss
    • 4. When the air is passed through an insulated chamber having sprays of water maintained at a temperature higher than the dew point temperature of entering air but lower than its dry bulb temperature, then the air is said to be

    • Options
    • A. cooled and humidified
    • B. cooled and dehumidified
    • C. heated and humidified
    • D. heated and dehumidified
    • Discuss
    • 5. The lowest temperature during the cycle in a vapour compression system occurs after

    • Options
    • A. compression
    • B. expansion
    • C. condensation
    • D. evaporation
    • Discuss
    • 6. The pressure at the inlet of a refrigerant compressor is called

    • Options
    • A. suction pressure
    • B. discharge pressure
    • C. critical pressure
    • D. back pressure
    • Discuss
    • 7. The power per tonne of refrigeration is

    • Options
    • A. 3.5/C.O.P.
    • B. C.O.P/3.5
    • C. 3.5 x C.O.P.
    • D. none of these
    • Discuss
    • 8. The angle on which the strength of the tool depends is

    • Options
    • A. rake angle
    • B. cutting angle
    • C. clearance angle
    • D. lip angle
    • Discuss
    • 9. In centreless grinding, the surface speed of regulating wheel is

    • Options
    • A. 5 to 15 m/min
    • B. 15 to 60 m/min
    • C. 60 to 90 m/min
    • D. 90 to 120 m/min
    • Discuss
    • 10. Which of the following statement is correct regarding grinding of high carbon steel?

    • Options
    • A. Grinding at high speed results in the reduction of chip thickness and cutting forces per grit.
    • B. Aluminium oxide wheels are employed.
    • C. The grinding wheel has to be of open structure.
    • D. all of the above
    • Discuss


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