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 Two plates spaced 150 mm apart are maintained at 1000°C and 70°C. The heat transfer will take place mainly by Convection Radiation Forced convection Free convection Convection Radiation Forced convection Free convection ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Which of the following has least value of conductivity? Glass Water Plastic Air Glass Water Plastic Air ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer In regenerator type heat exchanger, heat transfer takes place by Flow of hot and cold fluids alternately over a surface Direct mixing of hot and cold fluids A complete separation between hot and cold fluids Generation of heat again and again Flow of hot and cold fluids alternately over a surface Direct mixing of hot and cold fluids A complete separation between hot and cold fluids Generation of heat again and again ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer According to Stefan Boltzmann law, ideal radiators emit radiant energy at a rate proportional to Absolute temperature Fourth power of absolute temperature Fourth power of temperature Square of temperature Absolute temperature Fourth power of absolute temperature Fourth power of temperature Square of temperature ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The transfer of heat by molecular collision is smallest in Liquids None of these Solids Gases Liquids None of these Solids Gases ANSWER DOWNLOAD EXAMIANS APP
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