Heat and Mass Transfer In counter flow heat exchangers One fluid is in hottest state and other in coldest state at inlet Both the fluids at exit are in their hottest state Both the fluids at inlet are in their hottest state Both the fluids at inlet (of heat exchanger where hot fluid enters) are in their coldest state One fluid is in hottest state and other in coldest state at inlet Both the fluids at exit are in their hottest state Both the fluids at inlet are in their hottest state Both the fluids at inlet (of heat exchanger where hot fluid enters) are in their coldest state ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Reynolds number (RN) is given by (where h = Film coefficient, l = Linear dimension, V = Velocity of fluid, k = Thermal conductivity, t = Temperature, ρ = Density of fluid, cp = Specific heat at constant pressure, and μ = Coefficient of absolute viscosity) RN = ρ V l /μ RN = hl/k RN = μ cp/k RN = V²/t.cp RN = ρ V l /μ RN = hl/k RN = μ cp/k RN = V²/t.cp ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer According to Prevost theory of heat exchange It is impossible to transfer heat from low temperature source to t high temperature source Heat transfer in most of the cases takes place by combination of conduction, convection and radiation Heat transfer by radiation requires no medium All bodies above absolute zero emit radiation It is impossible to transfer heat from low temperature source to t high temperature source Heat transfer in most of the cases takes place by combination of conduction, convection and radiation Heat transfer by radiation requires no medium All bodies above absolute zero emit radiation ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The heat is transferred by conduction, convection and radiation in None of these Condensation of steam in condenser Boiler furnaces Melting of ice None of these Condensation of steam in condenser Boiler furnaces Melting of ice ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Two long parallel surfaces each of emissivity 0.7 are maintained at different temperatures and accordingly have radiation heat exchange between them. It is desired to reduce 75% of the radiant heat transfer by inserting thin parallel shields of emissivity 1 on both sides. The number of shields should be One Two Four Three One Two Four Three ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Thermal conductivity of non-metallic amorphous solids with decrease in temperature Remain constant May increase or decrease depending on temperature Decreases Increases Remain constant May increase or decrease depending on temperature Decreases Increases ANSWER DOWNLOAD EXAMIANS APP
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