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/2.3 (T₁ - T₂) log (r₂/r₁) Q = [2πlk (T₁ - T₂)]/2.3 log (r₂/r₁) Q = [2π (T₁ - T₂)]/2.3 lk log (r₂/r₁) Q = 2.3 log (r₂/r₁)/[2πlk (T₁ - T₂)] Q = = 2πlk/2.3 (T₁ - T₂) log (r₂/r₁) Q = [2πlk (T₁ - T₂)]/2.3 log (r₂/r₁) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The use of heat exchangers is made in Condensers and evaporators in refrigeration and air conditioning units Radiators in automobile All of these Condensers and boilers in steam plants Condensers and evaporators in refrigeration and air conditioning units Radiators in automobile All of these Condensers and boilers in steam plants ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer A perfect black body is one which Is black in colour Absorbs heat radiations of all wave lengths falling on it Transmits all heat radiations Reflects all heat Is black in colour Absorbs heat radiations of all wave lengths falling on it Transmits all heat radiations Reflects all heat ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The heat transfer takes place according to Kirchhoff's law Zeroth law of thermodynamics Second law of thermodynamics First law of thermodynamics Kirchhoff's law Zeroth law of thermodynamics Second law of thermodynamics First law of thermodynamics ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Total heat is the heat required to Change vapour into liquid Increase the temperature of a liquid or vapour Convert water into steam and superheat it Change liquid into vapour Change vapour into liquid Increase the temperature of a liquid or vapour Convert water into steam and superheat it Change liquid into vapour ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The value of the wave length for maximum emissive power is given by Stefan’s law Wine’s law Planck’s law Kirchhoff’s law Stefan’s law Wine’s law Planck’s law Kirchhoff’s law ANSWER DOWNLOAD EXAMIANS APP
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