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 = 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)] Q = [2π (T₁ - T₂)]/2.3 lk log (r₂/r₁) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The critical thickness of insulation for a sphere is h₀/2k 2k/h₀ k/h₀ h₀/k h₀/2k 2k/h₀ k/h₀ h₀/k ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The unit of Stefan Boltzmann constant is watt/cm3 °K watt/cm4 °K watt2/cm °K⁴ watt/cm2 °K⁴ watt/cm3 °K watt/cm4 °K watt2/cm °K⁴ watt/cm2 °K⁴ ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Depending on the radiating properties, body will be transparent when(Where a = absorptivity, p = reflectivity, x = transmissivity) 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 The amount of heat flow through a body by conduction is Dependent upon the material of the body Directly proportional to the surface area of the body All of these Directly proportional to the temperature difference on the two faces of the body Dependent upon the material of the body Directly proportional to the surface area of the body All of these Directly proportional to the temperature difference on the two faces of the body ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Conduction is a process of heat transfer From one particle of the body to another by the actual motion of the heated particles From a hot body to a cold body, in a straight line, without affecting the intervening medium None of these From one particle of the body to another without the actual motion of the particles From one particle of the body to another by the actual motion of the heated particles From a hot body to a cold body, in a straight line, without affecting the intervening medium None of these From one particle of the body to another without the actual motion of the particles ANSWER DOWNLOAD EXAMIANS APP
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