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 = S/ρk h = k/ ρS h = kρ/S h = ρS/k h = S/ρk h = k/ ρS h = kρ/S h = ρS/k ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The expression Q = ρ AT4 is called Newton Reichmann equation Stefan-Boltzmann equation Joseph-Stefan equation Fourier equation Newton Reichmann equation Stefan-Boltzmann equation Joseph-Stefan equation Fourier equation 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 Log mean temperature difference in case of counter flow compared to parallel flow will be Same Depends on other factors Less More Same Depends on other factors Less More ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Thermal conductivity of water in general with rise in temperature Remain constant May increase or decrease depending on temperature Increases Decreases Remain constant May increase or decrease depending on temperature Increases Decreases ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Fourier's law of heat conduction is valid for Three dimensional cases only One dimensional cases only Regular surfaces having non-uniform temperature gradients Two dimensional cases only Three dimensional cases only One dimensional cases only Regular surfaces having non-uniform temperature gradients Two dimensional cases only ANSWER DOWNLOAD EXAMIANS APP
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