Heat and Mass Transfer Unit of thermal conductivity in M.K.S. units is K calm/hr °C K cal/hr m² °C K cal/kg m² °C K cal m/hr m² °C K calm/hr °C K cal/hr m² °C K cal/kg m² °C K cal m/hr m² °C ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The heat transfer from a hot body to a cold body is directly proportional to the surface area and difference of temperatures between the two bodies. This statement is called Newton's law of heating Newton's law of cooling First law of thermodynamics Stefan's law Newton's law of heating Newton's law of cooling First law of thermodynamics Stefan's law ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The rate of energy transferred by convection to that by conduction is called Nusselt number Peclet number Stanton number Biot number Nusselt number Peclet number Stanton number Biot number ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Fouling factor is used When a liquid exchanges heat with a gas None of these In case of Newtonian fluids In heat exchanger design as a safety factor When a liquid exchanges heat with a gas None of these In case of Newtonian fluids In heat exchanger design as a safety factor 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 = 2.3 log (r₂/r₁)/[2πlk (T₁ - T₂)] Q = [2πlk (T₁ - T₂)]/2.3 log (r₂/r₁) Q = [2π (T₁ - T₂)]/2.3 lk log (r₂/r₁) Q = = 2πlk/2.3 (T₁ - T₂) log (r₂/r₁) Q = 2.3 log (r₂/r₁)/[2πlk (T₁ - T₂)] Q = [2πlk (T₁ - T₂)]/2.3 log (r₂/r₁) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The ratio of the thickness of thermal boundary layer to the thickness of hydrodynamic boundary layer is equal to (Prandtl number) n, where n is equal to =-1/3 1 -1 =-2/3 =-1/3 1 -1 =-2/3 ANSWER DOWNLOAD EXAMIANS APP
EXAMIANS