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 convection, stirring of the fluid and cleaning the heating surface. In radiation, increasing the temperature and reducing the emissivity. All of these In conduction, reduction in the thickness of the material and an increase in thermal conductivity. In convection, stirring of the fluid and cleaning the heating surface. In radiation, increasing the temperature and reducing the emissivity. ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer When absorptivity (α) = 1, reflectivity (ρ) = 0 and transmissivity (τ) = 0, then the body is said to be a Black body White body Opaque body Grey body Black body White body Opaque body Grey body ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Thermal conductivity of wood depends on Density Temperature All of these Moisture Density Temperature All of these Moisture 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 = 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) Q = = 2πlk/2.3 (T₁ - T₂) log (r₂/r₁) Q = [2π (T₁ - T₂)]/2.3 lk log (r₂/r₁) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The heat is transferred by conduction, convection and radiation in Condensation of steam in condenser Boiler furnaces Melting of ice None of these Condensation of steam in condenser Boiler furnaces Melting of ice None of these ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Depending on the radiating properties, a body will be opaque when P = 0, x = 0 and a = 1 P=1, x = 0 and a = 0 X = 0, a + p = 1 P = 0, x = 1 and a = 0 P = 0, x = 0 and a = 1 P=1, x = 0 and a = 0 X = 0, a + p = 1 P = 0, x = 1 and a = 0 ANSWER DOWNLOAD EXAMIANS APP
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