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Home Mechanical Engineering Heat Transfer, Refrigeration and Air Conditioning Comments

  • Question
  • The value of the wave length for maximum emissive power is given by


  • Options
  • A. Kirchhoff's law
  • B. Stefan's law
  • C. Wein's law
  • D. Planck's law

  • Correct Answer
  • Wein's law 


  • Heat Transfer, Refrigeration and Air Conditioning problems


    Search Results


    • 1. A designer chooses the values of fluid flow rates and specific heats in such a manner that the heat capacities of the two fluids are equal. A hot fluid enters the counter flow heat exchanger at 100° C and leaves at 60° C. A cold fluid enters the heat exchanger at 40° C. The mean temperature difference between the two fluids is

    • Options
    • A. 20°C
    • B. 40°C
    • C. 60°C
    • D. 66.7°C
    • Discuss
    • 2. The relative humidity lines on a psychrometric chart are

    • Options
    • A. vertical and uniformly spaced
    • B. horizontal and uniformly spaced
    • C. horizontal and non-uniformly spaced
    • D. curved lines
    • Discuss
    • 3. A vapour absorption refrigeration system

    • Options
    • A. gives noisy operation
    • B. gives quiet operation
    • C. requires little power consumption
    • D. cools below 0° C
    • Discuss
    • 4. Wet bulb temperature indicates the moisture content in air.

    • Options
    • A. Agree
    • B. Disagree
    • Discuss
    • 5. The drier in a refrigeration system removes moisture in the system.

    • Options
    • A. Correct
    • B. Incorrect
    • Discuss
    • 6. The __________ point of ammonia is -77.7°C.

    • Options
    • A. freezing
    • B. boiling
    • Discuss
    • 7. Environmental protection agencies advice against the use of chloro-fluoro-carbon refrigerants since

    • Options
    • A. these react with water vapour and cause acid rain
    • B. these react with plants and cause green-house effect
    • C. these react with oxygen and cause its depletion
    • D. these react with ozone layer
    • Discuss
    • 8. The heat is transferred by conduction, convection and radiation in

    • Options
    • A. melting of ice
    • B. boiler furnaces
    • C. condensation of steam in condenser
    • D. none of these
    • Discuss
    • 9. The by-pass factor of a cooling coil decreases with

    • Options
    • A. decrease in fin spacing and increase in number of rows
    • B. increase in fin spacing and increase in number of rows
    • C. increase in fin spacing and decrease in number of rows
    • D. decrease in fin spacing and decrease in number of rows
    • Discuss
    • 10. The expansion valve in a refrigerator controls the flow of refrigerant.

    • Options
    • A. Correct
    • B. Incorrect
    • Discuss


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