A grey body is one whose absorptivity does not vary with temperature and wave length of the incident ray.

More Questions from Heat Transfer, Refrigeration and Air Conditioning

• The wet bulb temperature during sensible cooling of air
• The colour of the flame of halide torch, in case of leakage of freon refrigerant, will change to
• In absorption vapour systems, the refrigerant widely used is R-12.
• In a spray washing system, if the temperature of water is higher than the dry bulb temperature of entering air, then the air is
• The final relative humidity of the air during cooling and dehumidification is generally __________ than that of entering air.
• The atmospheric air at dry bulb temperature of 15°C enters a heating coil maintained at 40°C. The air leaves the heating coil at 25°C. The by-pass factor of the heating coil is
• Prandtl number (PN) is given by PN = μ.cp/k.
• The transfer of heat by molecular collision is smallest in
• A composite slab has two layers of different materials with thermal conductivities k1 and k2. If each layer has the same thickness, then the equivalent thermal conductivity of the slab will be
• The wet bulb depression indicates __________ humidity of the air.

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