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 2 k₁ k₂/ (k₁ + k₂) (k₁ + k₂)/ k₁ k₂ k₁ k₂ (k₁ + k₂) 2 k₁ k₂/ (k₁ + k₂) (k₁ + k₂)/ k₁ k₂ k₁ k₂ (k₁ + k₂) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Which of the following is expected to have highest thermal conductivity? Solid ice Melting ice Water Steam Solid ice Melting ice Water Steam 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 Three Two Four One Three Two Four One ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer In counter flow heat exchangers Both the fluids at inlet are in their hottest state One fluid is in hottest state and other in coldest state at inlet Both the fluids at inlet (of heat exchanger where hot fluid enters) are in their coldest state Both the fluids at exit are in their hottest state Both the fluids at inlet are in their hottest state One fluid is in hottest state and other in coldest state at inlet Both the fluids at inlet (of heat exchanger where hot fluid enters) are in their coldest state Both the fluids at exit are in their hottest state ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer A steam pipe is to be insulated by two insulating materials put over each other. For best results Better insulation should be put over pipe and better one over it Whether to put inferior OIL over pipe or the better one would depend on steam temperature Both may be put in any order Inferior insulation should be put over pipe and better one over it Better insulation should be put over pipe and better one over it Whether to put inferior OIL over pipe or the better one would depend on steam temperature Both may be put in any order Inferior insulation should be put over pipe and better one over it 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 =-2/3 =-1/3 -1 1 =-2/3 =-1/3 -1 ANSWER DOWNLOAD EXAMIANS APP
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