Heat and Mass Transfer The emissivity for a black body is 1 0.75 0.5 1 0.75 0.5 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The radiation emitted by a black body is known as Black radiation Total radiation Full radiation All of these Black radiation Total radiation Full radiation All of these 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 = [2π (T₁ - T₂)]/2.3 lk log (r₂/r₁) Q = 2.3 log (r₂/r₁)/[2πlk (T₁ - T₂)] Q = [2πlk (T₁ - T₂)]/2.3 log (r₂/r₁) Q = = 2πlk/2.3 (T₁ - T₂) log (r₂/r₁) Q = [2π (T₁ - T₂)]/2.3 lk 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 rate of heat flow through a body is Q = [kA (T₁ - T₂)]/x. The term x/kA is known as None of these Thermal conductivity Thermal resistance Thermal coefficient None of these Thermal conductivity Thermal resistance Thermal coefficient ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Which of the following would lead to a reduction in thermal resistance? All of these In conduction, reduction in the thickness of the material and an increase in thermal conductivity. In radiation, increasing the temperature and reducing the emissivity. In convection, stirring of the fluid and cleaning the heating surface. All of these In conduction, reduction in the thickness of the material and an increase in thermal conductivity. In radiation, increasing the temperature and reducing the emissivity. In convection, stirring of the fluid and cleaning the heating surface. 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 40°C 20°C 66.7°C 60°C 40°C 20°C 66.7°C ANSWER DOWNLOAD EXAMIANS APP
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