Heat and Mass Transfer Thermal diffusivity of a substance is given by (where h = Thermal diffusivity, ρ = Density of substance, S = Specific heat, and k = Thermal conductivity) h = kρ/S h = S/ρk h = ρS/k h = k/ ρS h = kρ/S h = S/ρk h = ρS/k h = k/ ρS ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The rate of energy emission from unit surface area through unit solid angle, along a normal to the surface, is known as Intensity of radiation Emissivity Transmissivity Reflectivity Intensity of radiation Emissivity Transmissivity Reflectivity ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer According to Stefan Boltzmann law, the total radiation from a black body per second per unit area is directly proportional to the Cube of the absolute temperature Square of the absolute temperature Absolute temperature Fourth power of the absolute temperature Cube of the absolute temperature Square of the absolute temperature Absolute temperature Fourth power of the absolute temperature ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Thermal conductivity of non-metallic amorphous solids with decrease in temperature Decreases Increases Remain constant May increase or decrease depending on temperature Decreases Increases Remain constant May increase or decrease depending on temperature ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Two long parallel surfaces each of emissivity 0.7 are maintained at different temperatures and accordingly have radiation heat exchange between them. It is desired to reduce 75% of the radiant heat transfer by inserting thin parallel shields of emissivity 1 on both sides. The number of shields should be One Four Two Three One Four Two Three 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. Directly proportional to None of these Inversely proportional to Equal to Directly proportional to None of these Inversely proportional to Equal to ANSWER DOWNLOAD EXAMIANS APP
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