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Mechanical Engineering :: Refrigeration and Air Conditioning

  1. Which of the following statement is correct?

  2. A.

     The human body can lose heat even if its temperature is less than the atmospheric temperature.

    B.

     The increase in air movement increases the evaporation from the human body.

    C.

     The warm air increases the rate of radiation of heat from the human body.

    D.

     Both (A) and (B)

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  3. Which of the following statement is correct?

  4. A.

     In vapour absorption refrigerator, the compression of refrigerant is avoided.

    B.

     Sub-cooling can be achieved by circulating more quantity of cooling water through the condenser.

    C.

     In vapour compression refrigeration, the vapour is drawn in the compressor cylinder during its suction stroke and is compressed adiabatically during the compression stroke.

    D.

     All of the above

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  5. For ammonia refrigerating systems, the tubes of a shell and tube condenser are made of

  6. A.

     Copper

    B.

     Aluminium

    C.

     Steel

    D.

     Brass

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  7. R-12 is generally preferred over R-22 in deep freezers since

  8. A.

     It has low operating pressures

    B.

     It gives higher coefficient of performance

    C.

     It is miscible with oil over large range of temperatures

    D.

     All of the above

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  9. A good refrigerant should have

  10. A.

     High latent heat of vaporisation and low freezing point

    B.

     High operating pressures and low freezing point

    C.

     High specific volume and high latent heat of vaporisation

    D.

     Low C.O.P. and low freezing point

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  11. Pick up the wrong statement. A refrigerant should have

  12. A.

     Tow specific heat of liquid

    B.

     High boiling point

    C.

     High latent heat of vaporisation

    D.

     Higher critical temperature

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  13. For proper refrigeration in a cabinet, if the temperature and vapour pressure difference between cabinet and atmosphere is high, then

  14. A.

     Bigger cabinet should be used

    B.

     Smaller cabinet should be used

    C.

     Perfectly tight vapour seal should be used

    D.

     Refrigerant with lower evaporation temperature should be used

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  15. The ratio of actual mass of water vapour in a given volume of moist air to the mass of water vapour in the same volume of saturated air at the same temperature and pressure, is called

  16. A.

     Humidity ratio

    B.

     Relative humidity

    C.

     Absolute humidity

    D.

     Degree of saturation

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  17. The ratio of the actual mass of water vapour in a unit mass of dry air to the mass of water vapour in the same mass of dry air when it is saturated at the same temperature and pressure, is called

  18. A.

     Humidity ratio

    B.

     Relative humidity

    C.

     Absolute humidity

    D.

     Degree of saturation

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  19. The capillary tube, as an expansion device, is used in

  20. A.

     Domestic refrigerators

    B.

     Water coolers

    C.

     Room air conditioners

    D.

     All of these

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