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Mechanical Engineering :: Refrigeration and Air Conditioning

  1. In a refrigerating machine, heat rejected is _________ heat absorbed.

  2. A.

     Equal to

    B.

     Less than

    C.

     Greater than

    D.

     None of these

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  3. During sensible heating of air _________ decreases.

  4. A.

     Wet bulb temperature

    B.

     Relative humidity

    C.

     Dry bulb temperature

    D.

     Specific humidity

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  5. During humidification process, __________ increases.

  6. A.

     Wet bulb temperature

    B.

     Relative humidity

    C.

     Dry bulb temperature

    D.

     Specific humidity

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  7. The boiling point of ________ is 10.5°C.

  8. A.

     Ammonia

    B.

     R-12

    C.

     Sulphur dioxide

    D.

     Carbon dioxide

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  9. Pick up the correct statement about giving up of heat from one medium to other in ammonia absorption system

  10. A.

     Strong solution to weak solution

    B.

     Weak solution to strong solution

    C.

     Strong solution to ammonia vapour

    D.

     Ammonia vapours to weak solution

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  11. An infinite parallel planes with emissivities e₁ and e₂, the interchange factor for radiation from surface 1 to surface 2 is given by

  12. A.

     (e₁ + e₂)/ e₁ + e₂ - e₁e₂

    B.

     1/e₁ + 1/e₂

    C.

     e₁ + e₂

    D.

     e₁e₂

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  13. A one tonne refrigerating machine means that

  14. A.

     One tonne is the total mass of machine

    B.

     One tonne refrigerant is used

    C.

     One tonne of water can be converted into ice

    D.

     One tonne of ice when melts from and at 0° C in 24 hours, the refrigeration effect is equivalent to 210 kJ/min

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  15. 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

  16. A.

     Cooled and humidified

    B.

     Cooled and dehumidified

    C.

     Heated and humidified

    D.

     Heated and dehumidified

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  17. The unit of thermal diffusivity is

  18. A.

     m/hK

    B.

     m/h

    C.

     m²/h

    D.

     m²/hK

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  19. Ammonia is

  20. A.

     Non-toxic

    B.

     Non-inflammable

    C.

     Toxic and non-inflammable

    D.

     Highly toxic and inflammable

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