Water In The Atmosphere - 1 - UPSC Geography Free MCQ Test with solutions

With the change of air temperature, the capacity to retain moisture increases or decreases and the relative humidity is also affected.

The air containing moisture to its full capacity at a given temperature is said to be saturated. The temperature at which saturation occurs in a given sample of air is known as the dew point.

The air becomes saturated when the capacity of containing moisture is full. At this point, air becomes incapable of holding any moisture. Condensation occurs and water vapour forms droplets in the form of clouds.

The transformation of water vapour into water is called condensation. It is caused by the loss of heat.

When air becomes saturated with water vapor, it cannot hold any more moisture. The excess water vapor condenses into tiny droplets, forming clouds. Rain may occur later if these droplets combine and grow heavy enough.

Orographic rainfall occurs when an airstream is forced to rise over a mountain range. The air becomes cooled and precipitation takes place.

Mid level clouds are called altostratus and altocumulus. The prefix “alto” indicates that they have cloud bases between 2 and 6 km above the ground.

Latent heat of water is the energy required to change its state or phase, without changing its temperature.

Rain shadow zone means Leeward side of the mountain. Areas lying in the rain shadow zone of the interior of the continents and high latitudes receive very low rainfall-less than 50 cm per annum.

The percentage of moisture present in the atmosphere as compared to its full capacity at a given temperature is known as the relative humidity. With the change of air temperature, the capacity to retain moisture increases or decreases and the relative humidity is also affected.