Heat and Mass Transfer A grey body is one whose absorptivity Does not vary with temperature and. wavelength of the incident ray Is equal to its emissivity Varies with wavelength of the incident ray Varies with temperature Does not vary with temperature and. wavelength of the incident ray Is equal to its emissivity Varies with wavelength of the incident ray Varies with temperature ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer According to Stefan's law, the total radiation from a black body per second per unit area is proportional to T Absolute temperature T2 T5 T Absolute temperature T2 T5 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The heat transfer by conduction through a thick cylinder (Q) is given by (where T₁ = Higher temperature, T₂ = Lower temperature, r₁ = Inside radius, r₂ = Outside radius, l = Length of cylinder, and k = Thermal conductivity) Q = = 2πlk/2.3 (T₁ - T₂) log (r₂/r₁) Q = [2πlk (T₁ - T₂)]/2.3 log (r₂/r₁) Q = [2π (T₁ - T₂)]/2.3 lk log (r₂/r₁) Q = 2.3 log (r₂/r₁)/[2πlk (T₁ - T₂)] Q = = 2πlk/2.3 (T₁ - T₂) log (r₂/r₁) Q = [2πlk (T₁ - T₂)]/2.3 log (r₂/r₁) Q = [2π (T₁ - T₂)]/2.3 lk log (r₂/r₁) Q = 2.3 log (r₂/r₁)/[2πlk (T₁ - T₂)] ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The most commonly used method for the design of duct size is the Equal friction method Dual or double method Static regains method Velocity reduction method Equal friction method Dual or double method Static regains method Velocity reduction method ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer A perfect black body is one which Transmits all heat radiations Is black in colour Reflects all heat Absorbs heat radiations of all wave lengths falling on it Transmits all heat radiations Is black in colour Reflects all heat Absorbs heat radiations of all wave lengths falling on it ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The total radiation from a black body per second per unit area is ________ fourth power of the absolute temperature. This statement is known as Stefan Boltzmann law. None of these Inversely proportional to Equal to Directly proportional to None of these Inversely proportional to Equal to Directly proportional to ANSWER DOWNLOAD EXAMIANS APP
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