Question

When does vapor turn into form of water or snow?

(a) Cooled below Dew point

(b) At Frost point

(c) When cooled Freezing point

(d) When there is rise in Humidity

This question was posed to me in an interview for job.

My question is based upon Hydrology topic in division Hydro Electric Power Plant of Energy Engineering

Answer 1

Right choice is (a) Cooled below Dew point

To explain I would say: Water is evaporated from surface of earth and stored in form of clouds. When the vapors in the atmosphere are cooled below dew point temperature, it falls in the form of water or snow depending on the atmospheric temperature.