Heat and Mass Transfer Thermal diffusivity of a substance is Directly proportional to the thermal conductivity All of these Inversely proportional to specific heat Inversely proportional to density of substance Directly proportional to the thermal conductivity All of these Inversely proportional to specific heat Inversely proportional to density of substance ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Absorptivity of a body will be equal to its emissivity At one particular temperature At critical temperature At all temperatures When system is under thermal equilibrium At one particular temperature At critical temperature At all temperatures When system is under thermal equilibrium ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer In convection heat transfer from hot flue gases to water tube, even though flow may be turbulent, a laminar flow region (boundary layer of film) exists close to the tube. The heat transfer through this film takes place by Conduction Both convection and conduction Convection Radiation Conduction Both convection and conduction Convection Radiation ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Stefan Boltzmann law is applicable for heat transfer by Convection Radiation Conduction Conduction and radiation combined Convection Radiation Conduction Conduction and radiation combined ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The ratio of the energy absorbed by the body to total energy falling on it is called Emissivity Emissive power Absorptivity Absorptive power Emissivity Emissive power Absorptivity Absorptive power 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 = 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) ANSWER DOWNLOAD EXAMIANS APP
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