ANS:C - 1

The Prandtl and Reynolds analogies are identical for a Prandtl number (��Pr) value of 1. In fluid dynamics, the Prandtl number (Pr) is a dimensionless number defined as the ratio of momentum diffusivity (kinematic viscosity) to thermal diffusivity. It is given by: =Kinematic viscosityThermal diffusivityPr=Thermal diffusivityKinematic viscosity​ When =1Pr=1, it indicates that the momentum diffusivity and thermal diffusivity of the fluid are equal. At this point, the Prandtl and Reynolds analogies become identical, simplifying the analysis of convective heat transfer. So, the correct option is: 1.