Heat and Mass Transfer A perfect black body is one which Is black in colour Absorbs heat radiations of all wave lengths falling on it Transmits all heat radiations Reflects all heat Is black in colour Absorbs heat radiations of all wave lengths falling on it Transmits all heat radiations Reflects all heat ANSWER DOWNLOAD EXAMIANS APP
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 A composite slab has two layers of different materials with thermal conductivities k₁ and k₂. If each layer has the same thickness, then the equivalent thermal conductivity of the slab will be (k₁ + k₂)/ k₁ k₂ (k₁ + k₂) k₁ k₂ 2 k₁ k₂/ (k₁ + k₂) (k₁ + k₂)/ k₁ k₂ (k₁ + k₂) k₁ k₂ 2 k₁ k₂/ (k₁ + k₂) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The rate of energy transferred by convection to that by conduction is called Nusselt number Stanton number Biot number Peclet number Nusselt number Stanton number Biot number Peclet number ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The heat transfer by conduction through a thick cylinder (Q) is given by (where T₁ = Higher temperature, T₂ = Lower temperature, r₁ = Inside radius, r₂ = Outside radius, l = Length of cylinder, and k = Thermal conductivity) Q = [2π (T₁ - T₂)]/2.3 lk log (r₂/r₁) Q = = 2πlk/2.3 (T₁ - T₂) log (r₂/r₁) Q = 2.3 log (r₂/r₁)/[2πlk (T₁ - T₂)] Q = [2πlk (T₁ - T₂)]/2.3 log (r₂/r₁) Q = [2π (T₁ - T₂)]/2.3 lk log (r₂/r₁) Q = = 2πlk/2.3 (T₁ - T₂) log (r₂/r₁) Q = 2.3 log (r₂/r₁)/[2πlk (T₁ - T₂)] Q = [2πlk (T₁ - T₂)]/2.3 log (r₂/r₁) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The use of heat exchangers is made in All of these Condensers and boilers in steam plants Radiators in automobile Condensers and evaporators in refrigeration and air conditioning units All of these Condensers and boilers in steam plants Radiators in automobile Condensers and evaporators in refrigeration and air conditioning units ANSWER DOWNLOAD EXAMIANS APP
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