Heat and Mass Transfer Depending on the radiating properties, a body will be black when(Where a = absorptivity, p = reflectivity, X = transmissivity.) P = 0, x = 1 and a = 0 P = 0, x = 0 and a = 1 P= 1, T = 0 and a = 0 X = 0, a + p = 0 P = 0, x = 1 and a = 0 P = 0, x = 0 and a = 1 P= 1, T = 0 and a = 0 X = 0, a + p = 0 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 = tm = (Δt1 - Δt2) loge (Δt1/Δt2) tm = loge (Δt1 - Δt2)/ Δt1/Δt2 tm = loge (Δt1/Δt2)/ (Δt1 - Δt2) tm = (Δt1 - Δt2)/ loge (Δt1/Δt2) tm = tm = (Δt1 - Δt2) loge (Δt1/Δt2) tm = loge (Δt1 - Δt2)/ Δt1/Δt2 tm = loge (Δt1/Δt2)/ (Δt1 - Δt2) tm = (Δt1 - Δt2)/ loge (Δt1/Δt2) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The total radiation from a black body per second per unit area is ________ fourth power of the absolute temperature. This statement is known as Stefan Boltzmann law. None of these Equal to Inversely proportional to Directly proportional to None of these Equal to Inversely proportional to Directly proportional to ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer A heat exchanger with heat transfer surface area A and overall heat transfer coefficient U handles two fluids of heat capacities Cmax and Cmin. The number of transfer units (NTU) used in the analysis of heat exchanger is specified as Cmin/U U.Cmin U/Cmin U/A.Cmin Cmin/U U.Cmin U/Cmin U/A.Cmin ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer According to Prevost theory of heat exchange Heat transfer by radiation requires no medium All bodies above absolute zero emit radiation It is impossible to transfer heat from low temperature source to t high temperature source Heat transfer in most of the cases takes place by combination of conduction, convection and radiation Heat transfer by radiation requires no medium All bodies above absolute zero emit radiation It is impossible to transfer heat from low temperature source to t high temperature source Heat transfer in most of the cases takes place by combination of conduction, convection and radiation ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer In regenerator type heat exchanger, heat transfer takes place by Generation of heat again and again Direct mixing of hot and cold fluids A complete separation between hot and cold fluids Flow of hot and cold fluids alternately over a surface Generation of heat again and again Direct mixing of hot and cold fluids A complete separation between hot and cold fluids Flow of hot and cold fluids alternately over a surface ANSWER DOWNLOAD EXAMIANS APP
EXAMIANS