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 In a heat exchanger with one fluid evaporating or condensing, the surface area required is least in Cross flow All of these Counter flow Parallel flow Cross flow All of these Counter flow Parallel flow ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer A cube at high temperature is immersed in a constant temperature bath. It loses heat from its top, bottom and side surfaces with heat transfer coefficients of h₁, h₂ and h₃ respectively. The average heat transfer coefficient for the cube is 1/h₁ + 1/h₂ + 1/h₃ (h₁.h₂.h₃)1/3 h₁ + h₂ + h₃ None of these 1/h₁ + 1/h₂ + 1/h₃ (h₁.h₂.h₃)1/3 h₁ + h₂ + h₃ None of these ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Film coefficient is defined as the ratio of Thickness of film of fluid to the thermal conductivity Thickness of film of fluid to the temperature drop through the films of fluids Thermal conductivity to the equivalent thickness of the film of fluid Temperature drop through the films of fluids to the thickness of film of fluids Thickness of film of fluid to the thermal conductivity Thickness of film of fluid to the temperature drop through the films of fluids Thermal conductivity to the equivalent thickness of the film of fluid Temperature drop through the films of fluids to the thickness of film of fluids ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Metals are good conductors of heat because They have high density Their atoms are relatively far apart Their atoms collide frequently They contain free electrons They have high density Their atoms are relatively far apart Their atoms collide frequently They contain free electrons ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The ratio of the thickness of thermal boundary layer to the thickness of hydrodynamic boundary layer is equal to (Prandtl number) n, where n is equal to 1 =-1/3 -1 =-2/3 1 =-1/3 -1 =-2/3 ANSWER DOWNLOAD EXAMIANS APP
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