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 =-1/3 1 =-2/3 -1 =-1/3 1 =-2/3 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Which of the following would lead to a reduction in thermal resistance? All of these In conduction, reduction in the thickness of the material and an increase in thermal conductivity. In convection, stirring of the fluid and cleaning the heating surface. In radiation, increasing the temperature and reducing the emissivity. All of these In conduction, reduction in the thickness of the material and an increase in thermal conductivity. In convection, stirring of the fluid and cleaning the heating surface. In radiation, increasing the temperature and reducing the emissivity. ANSWER DOWNLOAD EXAMIANS APP
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 = k/ ρS h = S/ρk h = ρS/k h = kρ/S h = k/ ρS h = S/ρk h = ρS/k h = kρ/S ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Which of the following has maximum value of thermal conductivity? Copper Steel Brass Aluminium Copper Steel Brass Aluminium ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Which of the following is a case of steady state heat transfer? I.C. engine None of these Air preheaters Heating of building in winter I.C. engine None of these Air preheaters Heating of building in winter ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The unit of overall coefficient of heat transfer is kcal/m hr °C kcal/hr °C kcal/m² kcal/m² hr °C kcal/m hr °C kcal/hr °C kcal/m² kcal/m² hr °C ANSWER DOWNLOAD EXAMIANS APP
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