Heat and Mass Transfer Which of the following property of air does not increase with rise in temperature? Dynamic viscosity Thermal diffusivity Density Thermal conductivity Dynamic viscosity Thermal diffusivity Density Thermal conductivity ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer 40% of incident radiant energy on the surface of a thermally transparent body is reflected back. If the transmissivity of the body be 0.15, then the emissivity of surface is 0.55 0.75 0.4 0.45 0.55 0.75 0.4 0.45 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Thermal diffusivity is a Function of temperature All of these Dimensionless parameter Physical property of a substance Function of temperature All of these Dimensionless parameter Physical property of a substance ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The total emissivity power is .defined as the total amount of radiation emitted by a black body per unit Thickness Temperature Area Time Thickness Temperature Area Time ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Conduction is a process of heat transfer None of these 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 From one particle of the body to another without the actual motion of the particles None of these 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 From one particle of the body to another without the actual motion of the particles 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 = = 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
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