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 = [2π (T₁ - T₂)]/2.3 lk log (r₂/r₁) Q = = 2πlk/2.3 (T₁ - T₂) log (r₂/r₁) Q = [2πlk (T₁ - T₂)]/2.3 log (r₂/r₁) Q = 2.3 log (r₂/r₁)/[2πlk (T₁ - T₂)] Q = [2π (T₁ - T₂)]/2.3 lk log (r₂/r₁) Q = = 2πlk/2.3 (T₁ - T₂) log (r₂/r₁) Q = [2πlk (T₁ - T₂)]/2.3 log (r₂/r₁) Q = 2.3 log (r₂/r₁)/[2πlk (T₁ - T₂)] ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Unit of thermal conductivity in S.I. units is W/m °K Option (B) and (C) above J/m °K sec J/m² sec W/m °K Option (B) and (C) above J/m °K sec J/m² sec ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The radiation emitted by a black body is known as Full radiation Total radiation Black radiation All of these Full radiation Total radiation Black radiation All of these ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Free convection flow depends on All of these Gravitational force Coefficient of viscosity Density All of these Gravitational force Coefficient of viscosity Density ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Depending on the radiating properties, a body will be opaque when 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 P = 0, x = 0 and a = 1 P=1, x = 0 and a = 0 X = 0, a + p = 1 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer A perfect black body is one which Transmits all heat radiations Reflects all heat Absorbs heat radiations of all wave lengths falling on it Is black in colour Transmits all heat radiations Reflects all heat Absorbs heat radiations of all wave lengths falling on it Is black in colour ANSWER DOWNLOAD EXAMIANS APP
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