Q1: If Prandtl number is greater than the Schmidt number, then the

ANS:A - thermal boundary layer lies inside the concentration boundary layer.

The Prandtl number (Pr) represents the ratio of momentum diffusivity (kinematic viscosity) to thermal diffusivity, while the Schmidt number (Sc) represents the ratio of momentum diffusivity to mass diffusivity. When the Prandtl number is greater than the Schmidt number (Pr>Sc), it means that thermal diffusivity is relatively higher compared to mass diffusivity. This condition typically occurs in situations where heat is transferred more readily than mass. In such cases, the thermal boundary layer tends to be thinner than the concentration boundary layer. This is because heat transfers more readily through the fluid, leading to a faster decrease in temperature near the surface compared to the decrease in concentration of a solute or species. So, if Pr>Sc, the thermal boundary layer lies inside the concentration boundary layer.