Heat and Mass Transfer According to Newton's law of cooling, the heat transfer from a hot body to a cold body is Directly proportional to the surface area Directly proportional to the difference of temperatures between the two bodies Both (A) and (B) Either (A) or (B) Directly proportional to the surface area Directly proportional to the difference of temperatures between the two bodies Both (A) and (B) Either (A) or (B) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer When α is absorptivity, ρ is reflectivity and τ is transmissivity, then for a diathermanous body, α = 0, ρ = 1 and τ = 0 α = 0, ρ = 0 and τ = 1 α + ρ = 1 and τ = 0 α = 1, ρ = 0 and τ = 0 α = 0, ρ = 1 and τ = 0 α = 0, ρ = 0 and τ = 1 α + ρ = 1 and τ = 0 α = 1, ρ = 0 and τ = 0 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The critical radius is the insulation radius at which the resistance to heat flow is Zero None of these Maximum Minimum Zero None of these Maximum Minimum 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/2.3 (T₁ - T₂) log (r₂/r₁) Q = [2π (T₁ - T₂)]/2.3 lk log (r₂/r₁) Q = [2πlk (T₁ - T₂)]/2.3 log (r₂/r₁) Q = 2.3 log (r₂/r₁)/[2πlk (T₁ - T₂)] Q = = 2πlk/2.3 (T₁ - T₂) log (r₂/r₁) Q = [2π (T₁ - T₂)]/2.3 lk log (r₂/r₁) Q = [2πlk (T₁ - T₂)]/2.3 log (r₂/r₁) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The transfer of heat by molecular collision is known as Radiation Convection Conduction None of these Radiation Convection Conduction None of these ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Total emissivity of polished silver compared to black body is Very much lower Higher Same More or less same Very much lower Higher Same More or less same ANSWER DOWNLOAD EXAMIANS APP
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