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Different forms of condensation are seen due to changes in atmospheric conditions.

70.8% of the earth’s surface is covered with water.

When the temperature in the atmosphere falls below the freezing point, water vapour directly turns into snowflakes this process is called sublimation.

• Rainfall is an important source of water on planet earth and rainfall is formed because of changes in the temperature of the air with water vapour. 
• The instrument that is used to measure rainfall is called rain gauge. 
• The funnel i.e. used for measuring rain has a specific diameter and the rain falling in this funnel is collected in bottle fitted in the gauge. 
• The collected water is then measured with the help of measuring jar. In the areas of heavy rainfall, the reading of the rain with rain gauge should be taken every three hours. The measuring jar reads rain in millimetres 
• The gauge has to be kept on open ground on 30cm high flat-mount. 
• So that the rain water is collected without any obstruction.

Correct answer is (d) 70.8%

If condensation and solidification of the water vapour in the atmosphere closer to the earth surface are visible, they are in the form of fog, dew or frost.

(i) Fog:

• The temperature of the layers of the air near the surface of the earth reduces. As the temperature reduces, water vapour condenses.
• In this process the water vapour turns into microscopic water particles and float in the air. 
• When the density of these droplets in the air increases it leads to the formation of fog

(ii) Dew:

• When moisture-laden air near the earth surface comes in contact with very cold objects condensation of water vapour takes place. 
• They turn into very small water droplets and stick to the surface of cold objects, e.g. eg: leaves and this is called dew.

(iii) Frost:

• When the temperature of the air reaches less then 0 degree Celcius the water droplet stuck to the surface of the cold objects and freezes.
• This frozen water droplet is called as frost.

Hails occur in summer reason in India.

(i) Convectional rainfall

(ii) Orographic rainfall

(iii) Cyclonic rainfall

• The main source of potable water available on the earth is precipitation. 
• As extreme rainfall is destructive so is the absence of rainfall.
• Floods may occur because of heavy rainfall and causes loss to life and property. 
• If precipitation does not take place then conditions of drought arise. It causes a shortage of food and food may have to be imported and farmers’ conditions becomes grave. 
• The economy of an agrarian1 country like India is dependent on agriculture. The agriculture in India to a large extent is dependent on monsoons. Hence rainfall in India is important to the whole country. 
• A good rainfall at the right time increases crop production while untimely rain can damage the crope. 
• Acid rains which is a combination of harmful gases and rainwater is harmful to the living organisms as well as non-living objects.

Hails do not occur in cold zones because of lack of upward flow.

• Orographic rainfall occurs in most parts of the world. 
• Convectional rainfall is regional in nature. 
• There is a certainty in the convectional rainfall occurring in the equatorial areas.
• Comparatively, the orographic and cyclonic rainfall is less certain. 
• And therefore, such areas are prone to very heavy rainfall, floods or droughts frequently.

(a) rainfall

(b) fog 

(c) hail 

(d) snow

Correct option is (c) orographic

• When the temperature in the atmosphere falls below the freezing point, the water vapour directly turns into snowflakes. This is called sublimation. 
• Here, the vapour in the form of gas transforms into solid snow. 
• Precipitation in the form of solid particles is known as snowfall. 
• In high latitudinal and temperate regions, snowfall occurs at the mean sea level while in tropical areas, snowfall occurs at places located higher than the snowline altitude.

• Cyclone is the specific air formation when the pressure at an area is less than the surrounding regions.
• Air from the surrounding region comes toward the center of the cyclone and starts moving upwards. 
• As it rises, the temperature of the air reduces, condensation occurs and rainfall takes place. 
• It rains in areas over which the cyclone passes. Cyclonic rainfall occurs more in temperate zones and its area is also quite extensive. 
• aComparatively, cyclonic rainfall occurring in tropical regions is limited in extent and is stormy in nature.

Correct option is (a) temperate

If a person is outside without any coverage, he needs to seek shelter immediately, making sure to protect his head from hailstones.

Hailstones are solid and heavy in nature and they hit the earth due to gravity and this is the reason they destroy the crops in the field.

Correct option is (d) hail

For the formation of hailstones the following conditions are required:

• Intense heating which results in upwards air flow. 
• The decrease in air temperature at higher layers of the atmosphere. 
• As India is a tropical country, we do not find cooler air at higher levels because of the intense heating of land.

• When there is a lot of heat on the earth’s surface, the upward air flow blows at a great speed. 
• Because of this upward flow, the temperature of the air reduces and the condensation of the water vapour takes place. 
• Dark clouds are formed. Because of the upward movement of air, these water droplets go at a higher altitude. 
• Here, solidification of these droplets occur and hailstones are formed.

(i) Orographic rainfall occurs in Maharashtra.

(ii) The rain shadow area lies to the Leeward side of Sahyadri hills (Maharashtra plateau).

(iii) The answer may vary.

• Strong vertical movements of air with very high difference in temperature are an ideal condition for the formation of hailstones. 
• Presence of moisture is also necessary in the air. 
• Such conditions do not exist frequently. 
• Hence hailstones are not experienced frequently.

Because we have a moderate temperature and we are closer to the sea, snow is not found in our surroundings.

Snow is found everywhere in winters of Kashmir because Kashmir is located at a higher altitude where the temperature falls below freezing point. Hence water vapour directly turn into snowflakes leading to snowfall.

Correct option is (c) 120mm

• As hailstones are heavy they fall towards the earth’s surface, but because of the frequent upward flow of air, they are repeatedly taken upwards. 
• Here, a new layer of snow encapsulates the hail. This happens quite a few times.
• Hence, concentric layers are formed while the hail grows in size. 
• These big heavy hailstones fall rapidly to the ground because of gravity. This type of precipitation is called as hail. 
• Hence due to hail, crops may get destroyed.

Correct option is (b) convectional

• In areas located at higher altitudes and highlatitudes, where the temperatures are below 0°C get precipitation in the form of snow. 
• Snow is friable and opaque. This snow accumulates in the form of layers on top of each other. 
• Because of the pressure from the upper layers, the lower layers of the snow become homogeneous, massive and transparent.
• Massive transparent snow formed in such a way is called ice.

Thus, there is a difference between ice and snow.

• Winds coming from Arabian sea are moisture-laden. They are obstructed by the Western Ghats coming in their way. 
• According to the slope of the Western Ghats, the moisture-laden winds start going upwards. 
• The temperature of these winds drop and condensation occurs and rainfall takes place. Thus, because of the obstruction of the Western Ghats, orographic rainfall occurs. 
• The windward side of the mountains gets more rain; amount of vapour in the air reduces after crossing the mountain and the water vapour carrying capacity of the air increases. 
• The leeward side of the mountain gets lesser rainfall and hence a rain-shadow area is formed here.

• In equatorial areas, the surface gets heated because of the sun’s heat and the air near it also gets heated. 
• As it gets heated, it spreads and becomes lighter and moves upwards. It cools down when it goes upward. The moisture-holding capacity of cold air is less. 
• Consequently, condensation of the water vapour occurs and rainfall occurs in equatorial areas.
• Thus in equatorial areas, convectional rainfall occurs almost daily in the afternoons.

Convectional rainfall is mainly experienced in equatorial region.

(i) Fog:

• The temperature of the layers of the air near the surface of the earth reduces. As temperature reduces, water vapour condenses.
• In this process, vapour turns into microscopic water particles and float in the air. 
• When the density of these droplets in the air increases, fog occurs.

(ii) Dew:

• When moisture-laden air near the earth’s surface comes in contact with very cold objects, condensation of the vapour takes place. They turn into very small water droplets. 
• These water droplets get stick to the surface of the cold objects. This is called dew.

(iii) Frost:

• If the temperature of the air reaches less than 0°C, the water droplets stuck to the surfaces of cold objects and freeze. 
• This frozen water droplet is called frost.