Heat and Mass Transfer The energy distribution of an ideal reflector at higher temperatures is largely in the range of Remain same at all wavelengths Wavelength has nothing to do with it Shorter wavelength Longer wavelength Remain same at all wavelengths Wavelength has nothing to do with it Shorter wavelength Longer wavelength ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The heat transfer takes place according to First law of thermodynamics Kirchhoff's law Zeroth law of thermodynamics Second law of thermodynamics First law of thermodynamics Kirchhoff's law Zeroth law of thermodynamics Second law of thermodynamics 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 = tm = (Δt1 - Δt2) loge (Δt1/Δt2) tm = loge (Δt1 - Δt2)/ Δt1/Δt2 tm = (Δt1 - Δt2)/ loge (Δt1/Δt2) tm = loge (Δt1/Δt2)/ (Δt1 - Δt2) tm = tm = (Δt1 - Δt2) loge (Δt1/Δt2) tm = loge (Δt1 - Δt2)/ Δt1/Δt2 tm = (Δt1 - Δt2)/ loge (Δt1/Δt2) tm = loge (Δt1/Δt2)/ (Δt1 - Δt2) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Thermal conductivity of air at room temperature in kcal/m hr °C is of the order of 0.002 0.01 0.02 0.1 0.002 0.01 0.02 0.1 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 2 k₁ k₂/ (k₁ + k₂) k₁ k₂ (k₁ + k₂) (k₁ + k₂)/ k₁ k₂ 2 k₁ k₂/ (k₁ + k₂) k₁ k₂ (k₁ + k₂) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer In counter flow heat exchangers Both the fluids at inlet are in their hottest state Both the fluids at exit 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 inlet are in their hottest state Both the fluids at exit 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 ANSWER DOWNLOAD EXAMIANS APP
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