Heat and Mass Transfer Thermal conductivity of water in general with rise in temperature Increases Decreases May increase or decrease depending on temperature Remain constant Increases Decreases May increase or decrease depending on temperature Remain constant ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer A designer chooses the values of fluid flow rates and specific heats in such a manner that the heat capacities of the two fluids are equal. A hot fluid enters the counter flow heat exchanger at 100°C and leaves at 60°C. A cold fluid enters the heat exchanger at 40°C. The mean temperature difference between the two fluids is 60°C 40°C 66.7°C 20°C 60°C 40°C 66.7°C 20°C ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Fourier's law of heat conduction gives the heat flow for One dimensional cases only Irregular surfaces Nonuniform temperature surfaces Two dimensional cases only One dimensional cases only Irregular surfaces Nonuniform temperature surfaces Two dimensional cases only 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 All of these Counter flow Parallel flow Cross flow All of these Counter flow Parallel flow Cross flow ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The most commonly used method for the design of duct size is the Equal friction method Static regains method Dual or double method Velocity reduction method Equal friction method Static regains method Dual or double method Velocity reduction method 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
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