Question

Which phenomenon occurs during the formation of clouds?
(A) Condensation
(B) Melting
(C) Evaporation
(D) Sublimation

Answer 1

Hint: Condensation is the process by which a change in physical state of matter occurs from gaseous phase to liquid phase. It is the opposite of vaporization, where the change in physical state is from gaseous phase to liquid phase.

Complete answer:
The formation of clouds is part of the water cycle. The water cycle or the hydrological cycle is the continuous movement of water above and below the surface of Earth. First, water evaporates from the surface of Earth from different water bodies. When moist air rises up, clouds are formed. As it rises, it gets colder and colder, and eventually the air becomes incapable of holding the water vapour in it. During this process, the water vapour condenses and forms small water droplets. These water droplets float in air, and form clouds. Since the change in physical state is from gaseous phase to liquid phase where the water vapour in the atmosphere turns into water droplets, the process undergone is condensation.
Hence, the required answer is (a) Condensation.

Note:
Melting, also known as fusion, is the change in physical state from solid phase to liquid phase. Evaporation is a type of vaporization, and is a surface phenomenon in which the change in physical state is from liquid to gaseous phase. Sublimation is the change in physical state from solid to gaseous phase directly, skipping the liquid phase.