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 = 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 tm = (Δt1 - Δt2)/ loge (Δt1/Δt2) tm = loge (Δt1/Δt2)/ (Δt1 - Δt2) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The emissivity for a black body is 0.5 1 0.75 0.5 1 0.75 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Log mean temperature difference in case of counter flow compared to parallel flow will be Depends on other factors Less More Same Depends on other factors Less More Same ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Which of the following property of air does not increase with rise in temperature? Dynamic viscosity Thermal diffusivity Thermal conductivity Density Dynamic viscosity Thermal diffusivity Thermal conductivity Density ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Upto the critical radius of insulation, Convective heat loss will be less than conductive heat loss Added insulation will increase heat loss Added insulation will decrease heat loss Heat flux will decrease Convective heat loss will be less than conductive heat loss Added insulation will increase heat loss Added insulation will decrease heat loss Heat flux will decrease ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Thermal diffusivity is a Function of temperature Dimensionless parameter All of these Physical property of a substance Function of temperature Dimensionless parameter All of these Physical property of a substance ANSWER DOWNLOAD EXAMIANS APP
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