Heat and Mass Transfer The thermal diffusivities for gases are generally More than those for solids More than those for liquids Less than those for liquids Dependent on the viscosity More than those for solids More than those for liquids Less than those for liquids Dependent on the viscosity ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The critical thickness of insulation for a sphere is k/h₀ 2k/h₀ h₀/2k h₀/k k/h₀ 2k/h₀ h₀/2k h₀/k ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer According to Newton's law of cooling, the heat transfer from a hot body to a cold body is Both (A) and (B) Either (A) or (B) Directly proportional to the surface area Directly proportional to the difference of temperatures between the two bodies Both (A) and (B) Either (A) or (B) Directly proportional to the surface area Directly proportional to the difference of temperatures between the two bodies ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer A designer chooses the values of fluid flow rates and specific heats in such a manner that the heat capacities of the two fluids are equal. A hot fluid enters the counter flow heat exchanger at 100°C and leaves at 60°C. A cold fluid enters the heat exchanger at 40°C. The mean temperature difference between the two fluids is 66.7°C 60°C 20°C 40°C 66.7°C 60°C 20°C 40°C ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Planck’s law holds good for polished bodies All of these black bodies all coloured bodies polished bodies All of these black bodies all coloured bodies ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Total emissivity of polished silver compared to black body is More or less same Same Higher Very much lower More or less same Same Higher Very much lower ANSWER DOWNLOAD EXAMIANS APP