Heat and Mass Transfer According to Kirchoff's law, the ratio of emissive power to absorptivity for all bodies is equal to the emissive power of a Red hot body Black body Brilliant white polished body Grey body Red hot body Black body Brilliant white polished body Grey body ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer When α is absorptivity, ρ is reflectivity and τ is transmissivity, then for a diathermanous body, α = 0, ρ = 1 and τ = 0 α + ρ = 1 and τ = 0 α = 0, ρ = 0 and τ = 1 α = 1, ρ = 0 and τ = 0 α = 0, ρ = 1 and τ = 0 α + ρ = 1 and τ = 0 α = 0, ρ = 0 and τ = 1 α = 1, ρ = 0 and τ = 0 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The value of Prandtl number for air is about 0.7 0.3 1.7 0.1 0.7 0.3 1.7 0.1 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The logarithmic mean temperature difference (tm) is given by (where Δt1 and Δt2 are temperature differences between the hot and cold fluids at entrance and exit) tm = (Δt1 - Δt2)/ loge (Δt1/Δt2) tm = loge (Δt1 - Δt2)/ Δt1/Δt2 tm = tm = (Δt1 - Δt2) loge (Δt1/Δt2) tm = loge (Δt1/Δt2)/ (Δt1 - Δt2) tm = (Δt1 - Δt2)/ loge (Δt1/Δt2) tm = loge (Δt1 - Δt2)/ Δt1/Δt2 tm = tm = (Δt1 - Δt2) loge (Δt1/Δt2) tm = loge (Δt1/Δt2)/ (Δt1 - Δt2) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Thermal diffusivity is a All of these Dimensionless parameter Function of temperature Physical property of a substance All of these Dimensionless parameter Function of temperature Physical property of a substance 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
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