Heat and Mass Transfer The critical thickness of insulation for a sphere is h₀/2k k/h₀ h₀/k 2k/h₀ h₀/2k k/h₀ h₀/k 2k/h₀ 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 = 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) tm = tm = (Δt1 - Δt2) loge (Δt1/Δt2) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Depending on the radiating properties, a body will be black when (Where a = absorptivity, p = reflectivity, X = transmissivity.) P= 1, T = 0 and a = 0 P = 0, x = 0 and a = 1 P = 0, x = 1 and a = 0 X = 0, a + p = 0 P= 1, T = 0 and a = 0 P = 0, x = 0 and a = 1 P = 0, x = 1 and a = 0 X = 0, a + p = 0 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The rate of energy transferred by convection to that by conduction is called Biot number Nusselt number Peclet number Stanton number Biot number Nusselt number Peclet number Stanton number ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Fourier's law of heat conduction gives the heat flow for Two dimensional cases only One dimensional cases only Irregular surfaces Nonuniform temperature surfaces Two dimensional cases only One dimensional cases only Irregular surfaces Nonuniform temperature surfaces ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer According to Prevost theory of heat exchange Heat transfer in most of the cases takes place by combination of conduction, convection and radiation Heat transfer by radiation requires no medium It is impossible to transfer heat from low temperature source to t high temperature source All bodies above absolute zero emit radiation Heat transfer in most of the cases takes place by combination of conduction, convection and radiation Heat transfer by radiation requires no medium It is impossible to transfer heat from low temperature source to t high temperature source All bodies above absolute zero emit radiation ANSWER DOWNLOAD EXAMIANS APP
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