Heat and Mass Transfer According to Stefan Boltzmann law, ideal radiators emit radiant energy at a rate proportional to Fourth power of temperature Square of temperature Fourth power of absolute temperature Absolute temperature Fourth power of temperature Square of temperature Fourth power of absolute temperature Absolute temperature 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 20°C 40°C 66.7°C 60°C 20°C 40°C 66.7°C ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Which of the following has least value of conductivity? Plastic Glass Water Air Plastic Glass Water Air 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
Heat and Mass Transfer The value of Prandtl number for air is about 0.3 0.7 1.7 0.1 0.3 0.7 1.7 0.1 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Moisture would find its way into insulation by vapour pressure unless it is prevented by High vapour pressure Less thermal conductivity insulator High thickness of insulation A vapour seal High vapour pressure Less thermal conductivity insulator High thickness of insulation A vapour seal ANSWER DOWNLOAD EXAMIANS APP
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