Which of the following has the lowest Prandtl number?

Question

Quizplus · Accepted Answer

The Prandtl number is a dimensionless number, essentially a ratio of momentum diffusivity (kinematic viscosity) to thermal diffusivity. It indicates the relative thickness of the momentum and thermal boundary layers. Fluids with low Prandtl numbers, like molten metals (e.g., molten sodium), have much thinner thermal boundary layers compared to their momentum boundary layers, because their thermal diffusivity is much higher than their viscosity. This is in contrast to fluids like water, transformer oil, and dilute H2SO4, which have higher Prandtl numbers due to their lower thermal diffusivities relative to their viscosities.

Which of the Following Has the Lowest Prandtl Number