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 = loge (Δt1/Δt2)/ (Δt1 - Δt2) tm = loge (Δt1 - Δt2)/ Δt1/Δt2 tm = tm = (Δt1 - Δt2) loge (Δt1/Δt2) tm = (Δt1 - Δt2)/ loge (Δt1/Δt2) tm = loge (Δt1/Δt2)/ (Δt1 - Δt2) tm = loge (Δt1 - Δt2)/ Δt1/Δt2 tm = tm = (Δt1 - Δt2) loge (Δt1/Δt2) tm = (Δt1 - Δt2)/ loge (Δt1/Δt2) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Thermal conductivity of water _________ with rise in temperature. Decreases Remain same Increases May increase or decrease depending upon temperature Decreases Remain same Increases May increase or decrease depending upon temperature ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer In case of liquids and gases, the heat transfer takes place according to Convection Conduction Radiation None of these Convection Conduction Radiation None of these ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Heat conducted through per unit area and unit thick face per unit time when temperature difference between opposite faces is unity, is called Temperature gradient Thermal coefficient Thermal conductivity Thermal resistance Temperature gradient Thermal coefficient Thermal conductivity Thermal resistance ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The critical temperature is the temperature Below which a gas does not obey gas laws Above which a gas will never liquefied Below which a gas is always liquefied Above which a gas may explode Below which a gas does not obey gas laws Above which a gas will never liquefied Below which a gas is always liquefied Above which a gas may explode ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Thermal diffusivity is Function of temperature Used as mathematical model A physical property of the material A dimensionless parameter Function of temperature Used as mathematical model A physical property of the material A dimensionless parameter ANSWER DOWNLOAD EXAMIANS APP
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