Heat and Mass Transfer Unit of thermal conductivity in S.I. units is J/m² sec Option (B) and (C) above J/m °K sec W/m °K J/m² sec Option (B) and (C) above J/m °K sec W/m °K ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The concept of overall coefficient of heat transfer is used in case of heat transfer by Radiation Convection Conduction Conduction and convection Radiation Convection Conduction Conduction and convection 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 66.7°C 40°C 60°C 20°C 66.7°C 40°C ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The unit of Stefan Boltzmann constant is watt2/cm °K⁴ watt/cm3 °K watt/cm2 °K⁴ watt/cm4 °K watt2/cm °K⁴ watt/cm3 °K watt/cm2 °K⁴ watt/cm4 °K 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 = = 2πlk/2.3 (T₁ - T₂) log (r₂/r₁) Q = [2πlk (T₁ - T₂)]/2.3 log (r₂/r₁) Q = [2π (T₁ - T₂)]/2.3 lk log (r₂/r₁) Q = 2.3 log (r₂/r₁)/[2πlk (T₁ - T₂)] Q = = 2πlk/2.3 (T₁ - T₂) log (r₂/r₁) Q = [2πlk (T₁ - T₂)]/2.3 log (r₂/r₁) Q = [2π (T₁ - T₂)]/2.3 lk log (r₂/r₁) Q = 2.3 log (r₂/r₁)/[2πlk (T₁ - T₂)] ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer A grey body is one whose absorptivity Is equal to its emissivity Does not vary with temperature and. wavelength of the incident ray Varies with wavelength of the incident ray Varies with temperature Is equal to its emissivity Does not vary with temperature and. wavelength of the incident ray Varies with wavelength of the incident ray Varies with temperature ANSWER DOWNLOAD EXAMIANS APP
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