Mechanical Engineering :: Heat Transfer,Refrigeration and Air Conditioning
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The wet bulb temperature during sensible heating of air
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The C.O.P. of an absorption type refrigerator is given by (where T1 = Temperature at which the working substance receives heat, T2 = Temperature of cooling water, and T3 = Evaporator temperature)
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Which of the following statement is wrong?
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In free convection heat transfer transition from laminar to turbulent flow is governed by the critical value of the
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In a refrigerating machine, heat rejected is __________ heat absorbed.
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The humidity ratio or specific humidity is the mass of water vapour present in
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The formation of frost on cooling coils in a refrigerator
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The by-pass factor for a cooling coil
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The difference between dry bulb temperature and wet bulb temperature, is called
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Defrosting of a refrigerator may be done by stopping the compressor for a short period.
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A.
The heat transfer in liquid and gases takes place according to convection.
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B.
The amount of heat flow through a body is dependent upon the material of the body.
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C.
The thermal conductivity of solid metals increases with rise in temperature,
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D.
Logarithmic mean temperature difference is not equal to the arithmetic mean temperature difference.
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A.
increases with increase in velocity of air passing through it
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B.
decreases with increase in velocity of air passing through it
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C.
remains unchanged with increase in velocity of air passing through it
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D.
may increase or decrease with increase in velocity of air passing through it depending upon the condition of air entering
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