Heat and Mass Transfer The total emissivity power is .defined as the total amount of radiation emitted by a black body per unit Thickness Time Area Temperature Thickness Time Area Temperature ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The amount of radiation mainly depends upon the Type of surface of the body All of these Nature of the body Temperature of the body Type of surface of the body All of these Nature of the body Temperature of the body ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The thermal diffusivities for gases are generally More than those for liquids More than those for solids Less than those for liquids Dependent on the viscosity More than those for liquids More than those for solids Less than those for liquids Dependent on the viscosity 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 emissivity for a black body is 0.5 0.75 1 0.5 0.75 1 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Which of the following has maximum value of thermal conductivity? Steel Aluminium Copper Brass Steel Aluminium Copper Brass ANSWER DOWNLOAD EXAMIANS APP
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