Question

In which one of the following cases will the liquid flow in a pipe be most streamlined

• A. Liquid of high viscosity and high density flowing through a pipe of small radius
• B. Liquid of high viscosity and low density flowing through a pipe of small radius
• C. Liquid of low viscosity and low density flowing through a pipe of large radius
• D. Liquid of low viscosity and high density flowing through a pipe of large radius

Answer 1

The correct option is B Liquid of high viscosity and low density flowing through a pipe of small radius

For streamline flow , Reynold's number $N_R\propto \frac{rp}{\eta }$ should be less.For less value of $N_R,$ radius and density should be small and viscosity should be high.