Heat and Mass Transfer The critical thickness of insulation for a sphere is h₀/k h₀/2k k/h₀ 2k/h₀ h₀/k h₀/2k k/h₀ 2k/h₀ 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 -1 =-2/3 =-1/3 1 -1 =-2/3 =-1/3 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Which of the following would lead to a reduction in thermal resistance? All of these In convection, stirring of the fluid and cleaning the heating surface. In conduction, reduction in the thickness of the material and an increase in thermal conductivity. In radiation, increasing the temperature and reducing the emissivity. All of these In convection, stirring of the fluid and cleaning the heating surface. In conduction, reduction in the thickness of the material and an increase in thermal conductivity. In radiation, increasing the temperature and reducing the emissivity. ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer If the energy radiated per second per sq. cm. of the surface for wave lengths lying between λ, and λ + dλ is represented by (eλ.dλ), then eλ is called Emissive power Absorptive power None of these Emissivity Emissive power Absorptive power None of these Emissivity ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Fourier's law of heat conduction gives the heat flow for Irregular surfaces Nonuniform temperature surfaces One dimensional cases only Two dimensional cases only Irregular surfaces Nonuniform temperature surfaces One dimensional cases only Two dimensional cases only ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The value of Prandtl number for air is about 0.7 1.7 0.1 0.3 0.7 1.7 0.1 0.3 ANSWER DOWNLOAD EXAMIANS APP
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