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Mechanical Engineering :: Heat Transfer,Refrigeration and Air Conditioning

  1. The final relative humidity of the air during cooling and dehumidification is generally __________ than that of entering air.

  2. A.
    lower
    B.
    higher

  3. The emissivity of a polished silver body is __________ as compared to black body.

  4. A.
    same
    B.
    low
    C.
    very low
    D.
    high

  5. In a pressure enthalpy chart, the space between the saturated liquid line and saturated vapour line, represents sub-cooled liquid region.

  6. A.
    True
    B.
    False

  7. R-11 has the highest critical point temperature.

  8. A.
    Correct
    B.
    Incorrect

  9. The ratio of heat extracted in the refrigerator to the workdone on the refrigerant is called

  10. A.
    coefficient of performance of refrigeration
    B.
    coefficient of performance of heat pump
    C.
    relative coefficient of performance
    D.
    refrigerating efficiency

  11. Air refrigerator works on

  12. A.
    reversed Carnot cycle
    B.
    Bell Coleman cycle
    C.
    both (a) and ib)
    D.
    none of these

  13. The reciprocating refrigerant compressors are very suitable for

  14. A.
    small displacements and low condensing pressures
    B.
    large displacements and high condensing pressures
    C.
    small displacements and high condensing pressures
    D.
    large displacements and low condensing pressures

  15. The boiling point of carbon dioxide is

  16. A.
    -20.5°C
    B.
    -50°C
    C.
    -63.3°C
    D.
    -78.3°C

  17. The mass of water vapour present in __________ is called absolute humidity.

  18. A.
    1 m3 of wetair
    B.
    1 m3 of dry air
    C.
    1 kg of wet air
    D.
    1 kg of dry air

  19. The relative coefficient of performance is equal to

  20. A.
    B.
    C.
    Actual C.O.P. x Theoretical C.O.P.
    D.
    none of these