Heat and Mass Transfer Thermal diffusivity of a substance is given by (where h = Thermal diffusivity, ρ = Density of substance, S = Specific heat, and k = Thermal conductivity) h = ρS/k h = kρ/S h = k/ ρS h = S/ρk h = ρS/k h = kρ/S h = k/ ρS h = S/ρk ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Wien’s law states that the wave length corresponding to ________ is proportional to the absolute temperature. Both (A) and (B) Minimum energy Maximum energy None of these Both (A) and (B) Minimum energy Maximum energy None of these ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer An ordinary passenger aircraft requires a cooling system of capacity. 10 TR 4 TR 2 TR 8 TR 10 TR 4 TR 2 TR 8 TR ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Cork is a good insulator because it has Atoms colliding frequency Porous body Low density Free electrons Atoms colliding frequency Porous body Low density Free electrons 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 = [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) Q = = 2πlk/2.3 (T₁ - T₂) log (r₂/r₁) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The expression Q = ρ AT4 is called Stefan-Boltzmann equation Newton Reichmann equation Fourier equation Joseph-Stefan equation Stefan-Boltzmann equation Newton Reichmann equation Fourier equation Joseph-Stefan equation ANSWER DOWNLOAD EXAMIANS APP
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