Category: CBSE Class 11

Here we are providing Class 11 Geography Important Extra Questions and Answers Chapter 6 Soils. Important Questions for Class 11 Geography are the best resource for students which helps in class 11 board exams.

Important Questions for Class 11 Geography Chapter 6 Soils

Soils Important Extra Questions Very Short Answer Type

Question 1.
What is soil?
Answer:
Soil is a layer of unconsolidated material at the surface of the earth which has been derived from rocks and organic matter.

Question 2.
How is soil formed?
Answer:
It is formed by gradual disintegration under the influence of various agents.

Question 3.
Name the major factors in the formation of soils.
Answer:
Parent material, relief, climate, vegetation and drainage.

Question 4.
Name the three horizons of the soil.
Answer:

1. A horizon – topmost
2. B horizon – less leached
3. C horizon – illuvial

Question 5.
Name the physical properties of the soil.
Answer:
Size, shape and arrangement of particles, the volume and effective depth of the soil.

Question 6.
What is ravine?
Answer:
It is a small narrow valley with steep sides. It is larger than a gully and smaller than a canyon.

Question 7.
Why soil conservation is important?
Answer:
Because it is the most important natural resource for plants, animals and human beings.

Question 8.
Define soil texture.
Answer:
Soil texture is the arrangement and relationship of particles of the soil.

Question 9.
What does the black colour of the soil indicate?
Answer:
It indicates the presence of rich organic matter in the soil.

Question 10.
What is meant by slight, moderate and severe erosion?
Answer:
If the soil erosion is less than 25% of the surface – light.

• If it is between 25%-75% – moderate.
• If it is more than 75% – severe.

Question 11.
Which organisms play an effective role in the fertility of the soil?
Answer:
These are bacteria, fungi, earthworms, ants and other insects and animals.

Question 12.
Which two groups the soils used to be classified into in ancient India?
Answer:
Urvara and Usara, meaning fertile and sterile respectively.

Question 13.
What does ICAR stand for?
Answer:
ICAR stands for Indian Council of Agricultural Research.

Question 14.
On which criteria, the ICAR classification is based?
Answer:
The ICAR classification is based on genesis, colour, composition and location.

Question 15.
Identify the various categories of soils in India as classified by ICAR.
Answer:
Alluvial soil, black soil, red and yellow soils, laterite soil, arid soils, saline soils, organic soil and forest soils.

Question 16.
What is Regur?
Answer:
‘Regur’ is black soil.

Question 17.
Which two types of soils have been developed in the upper and middle Ganga plain?
Answer:
Khadar and Bhangar. Khadar is a newer alluvial whereas Bhangar is older alluvial.

Question 18.
Give some examples of coarse grain.
Answer:
Jowar, Bajra, ragi, etc.

Question 19.
Which chemical is added to the soils in order to solve the problem of salinity?
Answer:
Gypsum is added to the soil in order to solve the problem of salinity.

Question 20.
What is ‘jumping’?
Answer:
‘Jumping’ is the name of shifting agriculture in India. This is the oldest type of agriculture. This is also known as ‘slash and bum’ method.

Question 21.
Which regions are known for cotton cultivation in India?
Answer:
The Deccan plateau and the Coimbatore upland are known for cotton cultivation in India.

Question 22.
Name the two most active agents of soil erosion.
Answer:
Wind and running water are the two active agents of soi 1 erosion.

Question 23.
What exhibits badland topography?
Answer:
Areas with poor vegetation and steep slope, particularly in undulating terrain and along with the river courses, often exhibit badland topography.

Question 24.
What are the ill effects of soil erosion?
Answer:
Ill effects of soil erosion are the removal of fertile soil, sudden and heavy floods, sitting of river beds, lowering of water bodies and lowering of the soil moisture.

Question 25.
Name three primary forms of soil structure.
Answer:
The three primary forms of soil structure are granular, blacky and peaty.

Question 26.
What are ferruginous gneiss and schist rocks?
Answer:
Time rocks containing iron are known as ferruginous gneiss and schist.

Question 27.
From which the black soil is derived?
Answer:

1. Deccan trap and
2. the ferruginous gneiss and schist rock.

Soils Important Extra Questions Short Answer Type

Question 1.
Explain how the soil organisms play an effective role in the fertility of the soil?
Answer:
A large number of soil organisms including bacteria, fungi, earthworms, ants, insects and animals play an effective role in the fertility of the soil. They multiply very quickly under favourable conditions and add nutrients to the soil.

Question 2.
How did the soils use to be classified in ancient India?
Answer:
In ancient India, the soils used to be classified into two main groups, viz., Urvara which were fertile and Usara which were sterile. The Urvara soils were subdivided into different types on the basis of crops grown, such as barley soil, rice soils, etc. Similarly, Usara soils were sub-divided into salt land, deserts, etc.

Question 3.
Discuss the types and characteristics of alluvial soils.
Answer:
Alluvial soils are depositional soils transported by the streams and winds. They are largely sandy loam in texture. The colour of the alluvial soils varies from light grey to ash grey. Its shades depend on the depth of the deposition, the texture of the materials, and the time taken for its formation.

Question 4.
What are ravines? How are they different from gullies?
Answer:
A ravine is a small, narrow valley with steep sides, larger than a gully, but smaller than a canyon.

A gully, on the other hand, is a narrow channel worn in the earth by water. It is especially a miniature valley resulting from a heavy downpour of rain. Further erosion and deepening of a gully leading to the formation of a ravine.

Question 5.
Differentiate among soil erosion, soil exhaustion and soil degradation.
Answer:
The removal of the soil by running water in wet areas and wind in dry areas is known as soil erosion. The removal of its organic and mineral content is referred to as soil exhaustion. Whereas the misuse of the soils leads to soil degradation i.e. decline in the quality of soil, However, the agencies involved in soil erosion, exhaustion and degradation are common. They are running water, wind, snow, animals and human beings.

Question 6.
Which elements are required by plants as nutrients?
Answer:
A large number of elements namely, carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, sulphur, magnesium, calcium, iron, manganese, zinc, copper, boron and molybdenum are required by a plant as nutrients.

Question 7.
Classify the soil on the basis of various types of water in India.
Answer:
There are four types of soils identified on the basis of different types of water. They are Barani, Chari, Nahari and sailable. Soils dependent on rainwater are called Barani, that on well irrigation Chari, that on canal irrigation Nahari and that on river percolation sailable.

Question 8.
Define alluvium.
Answer:
The alluvium is the unconsolidated, loose material left only soil but also the gravel and sand brought down by a river and deposited in its bed, flood plain, delta or estuary, or in a lake, or land down like cone deposits on the flood plains of the large rivers.

Question 9.
Which type of soil is derived from Deccan lavas? Explain its important characteristics?
Answer:
Black soil is derived from Deccan lavas. The important characteristics are:

1. It chemically consists of lime, iron, magnesia and alumina.
2. It is generally clayey, deep and impermeable.

It lacks in phosphorous, nitrogen and organic matter but contains potash.

Question 10.
Which type of soil is the most dominant type and where is it found? Describe its two properties.
Answer:
Alluvial soils are the most widespread soil covering an area of 8 lakh sq. km. from Punjab to Assam. It is found over about 43.7% area in India. It is found in river basins, flood plains and coastal areas. This soil is rich in potash but poor in nitrogen. Alluvial soi Is are of three types:

1. Khadar soils -f fine and deposited in flood plains.
2. Bangar soils – older alluvium soil.
3. Newest alluvial soils – fine alluvial soil found in delta.

Question 11.
What are the characteristics of laterite soils?
Answer:

1. The laterite soils are brick coloured.
2. These are shallow, acidic and less fertile.
3. these less fertile due to leaching of soil.
4. These are poor in nitrogen, potash but rich in iron. This is found in Tamil Nadu.

Question 12.
What is the parent material of soil?
Answer:
The soils are formed due to the weathering and erosion of rocks exposed on the surface. The material which has undergone weathering and erosion and had contributed to soil formation is known as the parent material. The type and nature of parent materials play a vital role in determining the properties of soil.

Question 13.
What is contour ploughing?
Answer:
The method of tilting or ploughing hillsides or sloping lands among the contour lines, that is, around rather than up and down a slope mainly with a view of conserving soil and water.

Question 14.
How can we improve the fertility of soils?
Answer:
The fertility of the soil means the presence of humus contents and enough soil nutrients which provides nourishment to the plants. To improve the fertility of the soil following methods should be used:

Question 15.
Distinguish between soil erosion and soil conservation.
Answer:

Soil erosion	Soil conservation
(1) Ills black in colour and hence called black soil.	(1) It is yellow in colour.
(2) It is formed by the decomposition of lava.	(2) It is formed by leaching in tropical areas.
(3) It is suitable for the cultivation of cotton.	(3) It is suitable for millets.
(4) Et is found in Deccan plateau.	(4) It is found over a low plateau in Bihar.

Soils Important Extra Questions Long Answer Type

Question 1.
Describe the areas affected by soil erosion. What are the factors responsible for it? Suggest measures to conserve it.
Answer:
The areas affected by the soil erosion are West Bengal, Uttar Pradesh, Madhya Pradesh, Maharashtra, Tamil Nadu, Karnataka, Delhi, Rajasthan and many other parts of India.

1. Potato cultivation in theregionofMeghalayaonNilgiri hills causes soil erosion.
2. Cleaning of forests in the Himalayas and on the Western Ghats.
3. Excessivegrazingbycattleontheslopesofhillscauserapidsoil erosion.
4. On steep slopes due to running water soil-erosion increases.
5. Strong winds cause soil erosion. They blow away soil in dry areas.
6. Heavy rainfall causes soil-erosion.
7. Jumping by the tribal population in different parts of the country have caused considerable depletion of the soils.
8. Deforestation causes soil erosion.

The followings are the measures to conserve the soils:

1. By scientific use of land.
2. Crop-rotation, contour ploughing and bunding.
3. Afforestation in the upper reaches of river basins.
4. Increased use of organic manures.
5. Construction of water barriers against gullies in wet regions.
6. Replacing flood irrigation by sprinklers and drip irrigation.

Question 2.
Write a short note on Arid soils and Saline soils.
Answer:
Arid soils – Arid soi 1 is red to brown in colour. They are generally sandy and alkaline. In some areas, the salt content is so high that common salt is obtained by evaporating the saline water. In a dry climate, due to high temperature and accelerated evaporation. They lack moisture and humus content is normal. Lower horizons of soils are occupied by Kankar due to increased calcium downward. This type of soil is found in Rajasthan where desert topography is found. These soils contain less humus and. organic matter. These are suitable for Jowar, Bajra, Ragi and oilseeds, etc.

Saline soils – These are known as Usara soils. It contains a larger portion of sodium, potassium and magnesium. It is poorly fertile. These require more salts largely because of the dry climate and poor drainage. These are found in arid and semi-arid regions and water-logged and swampy areas. Its structure ranges from sandy to loamy. It lacks nitrogen and calcium. Saline soils are found in the region of western Gujarat, deltas of the eastern coasts and Sunderban area of West Bengal. With the excessive use of cultivation and irrigation, the fertile alluvial soils are becoming saline.

Question 3.
Describe the major characteristics and distribution of the soils in India.
Answer:
Characteristics and distribution of soils in India:
1. Alluvial soil – It is fine silt deposited in the plains by rivers, brought from the mountain regions. It is very fertile and famous for agriculture. Relatively fine and new soil of the flood plains and deltas is known as Khadar and older deposits as Bangar. Great plains of the north and deltas of peninsular rivers abound in alluvial soil.

2. Black soil – Black soil is made of volcanic rocks of lava flows. The soil is fertile and clayey. It can maintain moisture for long periods. Due to black in colour, it is said to be black soil. Cotton is grown abundantly in this soil. Locally it is named as regur soil. Gujarat, parts of M.P. and Maharashtra have black soil over large areas.

3. Red soil – Red soil has developed on the crystalline igneous rocks. They are less fertile but with the help of manures and fertilisers, good crops are raised in it. Relatively hot and dry parts of southern and eastern peninsula abound in red soils.

4. Laterite soil – Due to heavy rains fertile portion of the soil has been washed away leading to leaching. Hence the soil is infertile. Hilly regions of Western Ghats and Chhotanagpur plateau with heavy rainfall and hot weather are represented by this type of soil.

5. Mountain soils are found in the Himalayan region. They are good for tea growing. Desert soil is found in Rajasthan. They are sandy and do not produce any significant crop.

Question 4.
Discuss the type of physical conditions leading to the formation of peaty and organic soils.
Answer:
The peaty and organic soils are found in the areas of heavy rainfall and high humidity, where there is a good growth of vegetation. A large amount of dead organic matter accumulates in these areas and this gives rich humus and organic content to the soil. Hence, they are peaty and organic soils. Organic matter in these soils may go even up to 40 to 50%.

These soils are normally heavy and black in colour. They occur widely in the northern part of Bihar, the southern part of Uttaranchal and coastal areas of West Bengal, Orissa and Tamil Nadu. Such soils are used for cultivation of high and less soil exhaustive crops.

Question 5.
(a) So long a balance exists between the processes of soils formation and soil erosion, there is no nutrient, but when the balance has distributed the erosion of the soil becomes a menace. Comment.
Answer:
The removal of soil by running water and the erosion process of running water and wind are continuous. Generally, there is a balance between these two processes. The rate of removal of fine particles from the surface is the same as the rate of addition of particles to the soil layer. Sometimes such a balance is distributed by natural or human factors, leading to a greater rate of removal of soil. When this happens, the entire soil layer may be removed in a few years.
Indiscriminate felling of trees, careless overgrazing of pasture lands, unscientific drainage operations and improper land use are some of the important causes which upset this balance.

(b) What are ravines? How are they different from gullies?
Answer:
Ravines: A ravine is a small narrow valley with steep sides, larger than a gully, but smaller than a canyon.

A gully, on the other hand, is a narrow channel worn in the earth by water. It is especially a miniature valley resulting from a heavy downpour of rain. Further erosion and deepening of a gully leading to the formation of a ravine.

Here we are providing Class 11 Geography Important Extra Questions and Answers Chapter 5 Natural Vegetation. Important Questions for Class 11 Geography are the best resource for students which helps in class 11 board exams.

Important Questions for Class 11 Geography Chapter 5 Natural Vegetation

Natural Vegetation Important Extra Questions Short Answer Type

Question 1.
What is natural vegetation?
Answer:
Natural vegetation means a plant community that has been left undisturbed over a long period of time, so as to allow its species to adjust themselves to climate and soil conditions as fully as possible. Natural vegetation is found in mountain regions,

Question 2.
How many types the natural vegetation in India can be classified into?
Answer:
Based on the structure, physiognomy and florists nature of the | plants, the natural vegetation in India can be divided into:

1. Tropical evergreen forests
2. Tropical dry deciduous and evergreen forests
3. Semi-desert and desert vegetation
4. Wetlands littoral and swamp forests
5. Montane vegetation
6. The grasses

Question 3.
What is boreal?
Answer:
The species which are brought from outside are known as exotic and about 40% of the plant species in India are found to be exotic. The plant species which are brought from the Sino-Tibetan area are known as ‘boreal’.

Question 4.
Describe the vegetation in central parts of the plateau.
Answer:
In the central part of the Indian plateau dry tropical or deciduous
and thorny vegetation is found. This region receives less than 70 cm. rainfall and is covered with thorn forest type of vegetation. This part! presents vast undulating poor grassland. Summer is very long and dry,
the landscape changes to the pale carpet of grasses with grey stone surfaces.

Question 5.
Give any three characteristic features of tropical deciduous forests.
Answer:

1. TheyarefoundonfoothillsofHimalayasandmanyparts of peninsular plateau.
2. During the dry season, they shed their leaves. Teak, Shisham, sal, rosewood are the main species.
3. They have important economical significance.

Question 6.
What do you mean by biosphere reserve? Where and when was the first biosphere reserve of India developed?
Answer:
The vast areas which have been reserved for the preservation and protection of flora and fauna of the country in their natural form are known as bio-reserves. In these areas, the plants and animals are kept to protect for the future generation. The first Biosphere in India was developed at Nilgiri.

Question 7.
Describe the location and characteristic features of Kaziranga National Park.
Answer:
Kaziranga National Park is located inNagaonandGolaghatdistricts on the southern bank of Brahmaputra river at the foot of Mikir hills. It lies in the flood plains of the Brahmaputra river. The riverine habitat consists primarily of tall, dense grasslands interspersed with open forests. One homed rhinoceros and elephants are the main inhabitants of this park.

Question 8.
Write a short note on Sundarbans Biosphere Reserve.
Answer:
It is located in the swampy delta of the two great Indian rivers the Brahmaputra and the Ganga in West Bengal. It extends over a vast area of mangrove forest, swamps and forested islands, covering over 1300 sq. km. Sunderban is the home of nearly 200 Royal Bengal Tigers. Adapting themself to the saline and freshwater environment, the tigers at the park are good swimmers.

Question 9.
How can we utilise our forests resources for the future? Give three methods.
Answer:

1. We have to stop the reckless cutting of forests.
2. To reduce the pressure on forests, the substituent of timber should be found out.
3. To fulfil the basic needs of fuel and fodder of the people, social forestry and farmer forestry should be introduced.
4. More and more trees should be planted.

Question 10.
Name the various Bio-reserves in India.
Answer:

1. Nilgiri (Karnataka)
2. Nanda Devi (Uttranchal)
3. No Krek (Meghalaya)
4. Andaman Nicobar
5. Valley of flowers (Uttranchal)
6. Gulf of Mannar (Tamil Nadu)
7. Rann of Kutchh (Gujarat)
8. Kaziranga National Park (Assam)

Question 11.
What are the characteristic features of the tropical evergreen forests?
Answer:

1. There is a dense growth of vegetation which causes difficulty. of accessibility. A number of species are very large.
2. There is a lack of pure stands.
3. High temperature and heavy rainfall make conditions unsuitable for living.

Question 12.
What is the difference between National parks and Sanctuaries?
Answer:

National parks	Sanctuaries
(1) This is an area of multi ecosystems.	(1) The area of wildlife sanctuaries are also dedicated to protecting wildlife and species.
(2) This area has not been materially altered by human occu¬pation.	(2) There is no entry without permission.
(3) This is dedicated to protecting wildlife.	(3) Hunting and grazing are prohibited.
(4) Plant and animal species, for scientific education, recreation and geomorphological sites are present.	(4) Man’s activity is allowed in the sanctuaries.

Question 13.
How vegetation is different from forests?
Answer:
Vegetation is not limited to forests only. It is something more than the forests. Vegetation includes trees, grasses, shrubs, etc. Vegetation gives a distinct type of landscape to the region as grassland, woodland.

Forests are all type of vegetation. It refers to the society of trees in close growth. Forests are very useful for mankind.

Question 14.
Define reafforestation and afforestation.
Answer:
Reafforestation is the saplings of two plants which are planted to replace every felled tree. It is practised to avoid the evils of Jumping.

Afforestation is the planting of one sapling to get one tree. It is practised to bring more area under forest.

Natural Vegetation Important Extra Questions Long Answer Type

Question 1.
Why have certain species of animals become extinct in our country? What is being done to preserve wildlife?
Answer:
Wildlife has a very important role for mankind. But we have depleted its habitat, the forests, very fast. We have hunted wild animals and poached them indiscriminately. The result is that many of these wild animals face the danger of extinction. The major animals which face extinction are antelopes, lion, tigers, blackbuck, bustard, etc. Hence, to see the future need, there is an urgent need to conserve them.

Steps to be taken to preserve wild-life:

1. Hunting and poaching of wild animals have been banned.
2. Strict and severe punishment is accorded to defaulters.
3. National parks, zoos, sanctuaries and biosphere reserves have been set up more and more in number all over the country.
4. Maintenance of the existing trees.
5. More and more birds and animals are being declared national birds and animals.
6. ‘Project Tiger’ and ‘Project Elephant’ programmes have been ‘ launched to preserve and conserve wildlife.

Question 2.
Describe the various regions of concentration of forests in varying degrees in India.
Answer:
On the basis of the percentage of the actual forest cover, the states have been grouped into four regions. They are:

1. The region of high concentration
2. The region of medium concentration
3. The region of low concentration
4. The region of very low concentration

1. The region of the high concentration-This region includes the states where the percentage cover of the forest is more than 40%. All the eastern states except Assam fall in this category. Favourable climate, especially rainfall and temperature, is responsible for the high concentration of forests. There is variation in forest cover in the region. In the states of Mizoram, Nagaland and Arunachal Pradesh and in the Union Territory of Andaman and Nicobar Islands, forests occupy more than 80% of the geographical area. Manipur Meghalaya, Tripura, Sikkim and Dadra and Nagar Haveli have a percentage of forest between 40 and 80.

2. The region of moderate concentration – It includes the states of Madhya Pradesh, Orissa, Goa, Kerala, Assam and Himachal Pradesh. Goa has the lightest (33.79)% of the actual forest followed by Orissa and Assam. Rest of the states have less than 30% of their area.

3. The region of low concentration – This region is also not continuous. The states of Maharashtra, Karnataka, Andhra Pradesh and Tamil Nadu form peninsular sub-region while those of Uttar Pradesh and Bihar form the northern sub-region.

4. The region of very low concentration – The northwestern part of India falls in this category. The states included are Rajasthan, Punjab, Haryana, Gujarat, Chandigarh and Delhi. West Bengal in the east also comes under this region. Physical and human factors have been responsible for a very low concentration of forests in these areas.

Question 3.
Write a short note on the strange creatures of India.
Answer:
The strange creatures of India are Gangetic dolphin, Civets, Indian Pangolin, GreatlndianHorbill, Indian giant squirrel, mouse, deer and flying-fox.

Gangetic Dolphin – It lives in the Ganga river. It is born blind and lives sightless for the rest of its life.

Civets- It is a cat I like creature, lives solitary, comes out at night to hunt small birds, mammals and reptiles. It remains hiding during the day.

Indian pangolin – It has a scaly body. As protection against predators, it rolls itself into a ball and raises its sharp scales.

Great Indian Hornbill – It is a large bird with strange nesting habits; the female seal herself into d hollow in a tree and the male dutifully brings her food during the entire period of incubation.

Indian giant squirrel – It is a large nocturnal rodent which lives in the upper canopy of trees. It flaps between its body and its extremities act like parachutes and enable the large mammal to glide from tree to tree.

Mouse deer-This is a deer of 30 cm. in height. To evade predators, it hides beneath the low bushes and vegetation.

Flying fox – It is one of the world’s largest bats and is found all over India. Its wingspan is more than 1.5 m. and can fly over 220 km.

Question 4.
What is a Biosphere reserve? How many Biospheres are found in India? Describe in short.
Answer:
A Biosphere Reserve is a unique and representative ecosystem of terrestrial and coastal areas which are internationally recognized within the framework of UNESCO’S Man and Biosphere Programme.

There are 4 biosphere reserves in India. Four biosphere reserves namely

1. Nilgiri,
2. Nanda Devi,
3. Sunderbans,
4. Gulf of Mannar has been recognised by UNESCO on world network.

1. Nilgiri Biosphere Reserve- It is the first of the fourteen biosphere reserves of India and was established in September 1986. The total area of the biosphere reserve is around 5520 sq. km. Nilgiri Biosphere Reserve possesses different habitat types, unspoilt areas of natural vegetation types with several dry and moist deciduous, semi-evergreen and wet evergreen forests, evergreen sholes, grasslands and swamps. It includes the largest known population of two endangered animal species, namely the Nilgiri Tahr and the Lion-tailed Macaque. About 80% of the flowering plants reported from the Western Ghats occur in the Nilgiri Biosphere Reserve.

2. Nanda Devi Biosphere Reserve – It is situated in Uttranchal, includes parts of Chamoli, Almora, Pithoragarh and Bageshwar districts. The major type of the reserve is temperate forest. A few important species are silverweed, orchids, Latifolie and rhododendron. The biosphere reserve has a rich fauna, for example, snow leopard, black bear, brown bear, musk deer, snow-cock, golden eagle.

3. Sundarban Biosphere Reserve – This reserve is located in the swampy delta of the river Ganga in West Bengal. It spreads over a vast area of 9,630 sq. km and consists of mangrove forests, swamps and s- forested islands. It is a home of nearly 200 Royal Bengal Tigers.

4. Gulf of Mannar Biosphere Reserve – It covers an area of 1,05,000 hectares on the south-east coast of India from Sri-Lanka. The biosphere reserve comprises 21 islands with estuaries, beaches, forests of the nearshore environment, seagrass, coral reefs and mangroves.

Question 5.
Describe the importance of social forestry in India.
Answer:
The social forestry was used for the first time by the National Commission on Agriculture in 1976 to denote tree raising programmes to supply firewood, small hunters and minor forest produce to the rural population. Ambitious social forestry programmes have been launched by several state governments. The forest departments in most states have set up separate social forestry wings.

Social forestry programmes have mainly three components viz., farm forestry, wood lots and community wood lots. Farm forestry encourages farmers to plant trees on their own farmer; wood lots are planted by the forest departments for the needs of the community especially along roadsides, canal banks and other such public lands, and community wood lots are planted by the community themselves on community lands, to be shared equally by them.

Here we are providing Class 11 Geography Important Extra Questions and Answers Chapter 10 Atmospheric Circulation and Weather Systems. Important Questions for Class 11 Geography are the best resource for students which helps in class 11 board exams.

Important Questions for Class 11 Geography Chapter 10 Atmospheric Circulation and Weather Systems

Atmospheric Circulation and Weather Systems Important Extra Questions Very Short Answer Type

Question 1.
What is atmospheric pressure?
Answer:
Atmospheric pressure is the weight of the column of air on the surface of the earth at sea level.

Question 2.
What is atmospheric pressure at sea-level?
Answer:
The atmospheric pressure at sea level is about 1 kilogram per cm2.

Question 3.
What are factors determining the amount of pressure at a particular point?
Answer:
The amount of pressure exerted by air at a particular time is determined by temperature and density.

Question 4.
How the air pressure is the measure?
Answer:
The air pressure is measured as a force per unit area. The units of measurements are millibar (Mb).

Question 5.
What kind of relationship exists between pressure and temperature?
Answer:
There exists an inverse relationship between pressure and temperature.

Question 6.
In which direction the earth rotates on its axis?
Answer:
On its axis, the earth rotates from west to east.

Question 7.
How many pressure belts are there in all?
Answer:
There are seven pressure belts in all.

Question 8.
Give the latitudinal extent of the sub-polar low-pressure belt.
Answer:
Between 45” North and Arctic Circle in the northern hemisphere, and 45° South and Antarctic Circle in the southern hemisphere.

Question 9.
What are the other names used for westerlies?
Answer:
The other names used for westerlies are ‘roaring forties’, ‘furious fifties’, and ‘striking sixties’.

Question 10.
Name two places with the heaviest rainfall in India.
Answer:
The two places with the heaviest rainfall in India are Mawsinram and Cherrapunji.

Question 11.
What do the properties of air masses include?
Answer:
The properties of air masses include their temperature, humidity, hydrostatic moisture content, stability, and abundance of minor content.

Question 12.
Where are the polar maritime air masses located?
Answer:
They are located over warmer high latitude oceans of North Pacific, North Atlantic Ocean, and entire sweep of southern hemisphere oceans, fringing Antarctica.

Question 13.
Give the full form of ITCZ.
Answer:
Inter-Tropical Convergence Zone.

Question 14.
What is a millibar?
Answer:
It is a unit of measurement of atmospheric pressure.

Question 15.
What are the two types of pressure systems?
Answer:
The two types of pressure systems are high-pressure systems and low-pressure systems.

Question 16.
What is a pressure gradient?
Answer:
The pressure gradient is defined as the decrease in pressure per unit distance in the direction in which the pressure decreases most rapidly.

Question 17.
What are isobars?
Answer:
The isobars are imaginary lines drawn through places having equal atmospheric pressure at sea-level.

Question 18.
Why does pressure decrease with altitude?
Answer:
Because the air becomes thinner or its density decreases rapidly upwards from the surface of the earth.

Question 19.
What are tertiary winds?
Answer:
These are local winds like land and sea breeze.

Question 20.
Name the instrument by which the atmospheric pressure is measured.
Answer:
Barometer.

Question 21.
What is the standard sea-level pressure in millibars?
Answer:
1013.25 Mb.

Question 22.
How do air pressure and winds influence the weather?
Answer:
They control temperature and precipitation.

Question 23.
What is the normal rate of pressure decrease with altitude?
Answer:
1 Mb for every ascent of 110 meters.

Question 24.
Name the hot winds which blow in the USA and Canada.
Answer:
Chinook.

Question 25.
Where do you find the maximum and minimum deflection of winds by the Coriolis effect?
Answer:
At poles and equator respectively.

Question 26.
Name two broad types of cyclones.
Answer:
Temperate and tropical cyclones.

Question 27.
What are the two other names of temperate cyclones?
Answer:
Depressions and western disturbances.

Atmospheric Circulation and Weather Systems Important Extra Questions Short Answer Type

Question 1.
How do air pressure and winds influence the weather?
Answer:
Air pressure and winds control temperature and precipitation. Even a minor change in pressure changes the velocity and direction of winds and this, in turn, brings about changes in temperature and precipitation.

Question 2.
What is Coriolis force and who discovered it first?
Answer:
On the rotating earth, a point on the equator moves the fastest. As we go towards the poles, the speed decreases, reaching about zero at the pole. It is because of this difference in speed that any moving body, such as winds and ocean currents, gets deflected when it moves towards the equator or away from the equator. This force or deflection is called Coriolis. It was discovered by Coriolis, a French mathematician.

Question 3.
Explain Ferrel’s law.
Answer:
Ferrel’s law states that all moving bodies like wind and ocean currents get deflected from their normal paths towards the right in the northern hemisphere and towards the left in the southern hemisphere. The role of deflection increases with the distance from the equator. As a result, by the time the poleward directed winds reach 25 degrees latitude, they are deflected into nearly west to east flow.

Question 4.
Explain the occurrence and importance of ITCZ.
Answer:
The ITCZ means Inter-Tropical Convergence Zone. It is also known as Inter-Tropical Front (ITF). It is an equatorial front. It is a broad trough of low pressure defined more sharply over land than over the ocean. The tropical maritime air masses converge here. In ITCZ, the north-east trade winds and the south-east trade winds meet. This zone is mainly stationed over the equator but moves north and south according to the season. The air mass may be almost stagnant, the winds light and variable. Hence the air belt is calm, known as doldrums.

Question 5.
What is a pressure gradient?
Answer:
The pressure gradient is the rate at which pressure rises or falls. The gradient is steep when pressure changes in a short distance and mild when pressure changes at long distances. The pressure gradient is shown by isobars. When isobars are closer, the pressure gradient is steep and vice-versa.

Question 6.
What are tertiary winds?
Answer:
These winds are generated by the influence of the surrounding terrain. They include mountain and valley winds, land and sea-breezes, and other local winds such as loo, foehn, chinook and mistral, etc. Some winds are hot and some winds are cold winds. All are local winds.

Question 7.
What are roaring forties?
Answer:
The southern hemisphere has mostly sea and very little land. Westerlies, therefore, blow without any hindrance and with great velocity. Their roar can be heard far and wide. The westerlies here are called roaring forties.

Question 8.
Give the relation between pressure and temperature.
Answer:
The pressure and temperature have an inverse relationship with each other. As the air gets heated, it expands and rises upwards. The higher the temperature, the lower is the pressure. On the other hand, cold air contracts and becomes heavy. It results in high pressure.

Question 9.
What do you understand by Horse Latitude?
Answer:
The latitudes near the tropics are known as horse latitudes. In this zone, no permanent winds blow. It is a region of high pressure due to descending winds.

The sailing ships from Europe to America had to face problems due to the absence of backing winds. Therefore, some horses were thrown into the sea to make their ships lighter and to move further. This is why these latitudes are known as horse latitudes.

Question 10.
What is a jet stream? Explain.
Answer:
The winds with a high velocity which blow at high altitude are called the jet stream. This strong current of air is located near 90° north latitude. It affects the weather patterns of the world. High flying planes use these as super tailwinds to save time and fuel.

Question 11.
Describe the local winds in brief.
Answer:
Winds having special characteristics under local conditions are known as local winds.

1. Hot winds: Chinook in Canada and USA, foehn in Switzerland.
2. Dry winds: Sirocco in south Europe, Khanzim in Egypt, Hermatton in West Africa, Simoon of Arabia, Santa Anna of California, Zenda of Argentina.
3. Cold winds: Boro and Mistral in Southern Europe, Pampero in Argentina, Buran in Siberia.

Question 12.
Write a short note on ‘doldrums’.
Answer:
The doldrum is an equatorial low-pressure belt between 5°N to 5°S latitudes. It is known as the-belt of calm. The air is constantly heated due to the high temperature. The air expands and rises as convection currents. There are no surface winds. Sailing ships often found them becalmed in this belt due to the absence of backing winds.

Question 13.
What is the importance of air mass?
Answer:
Air mass is important for climatological study. Air masses are related to atmospheric disturbances, cyclones, storms, and fronts.

• The distribution and location of air provide an essential understanding of regional climate.
• Air masses transfer heat from lower latitude to higher latitudes.
• Atmosphericdisturbancesdevelopalongfrontsofdifferentairmasses.
• Air masses are associated with particular types of wind belts and determine the weather characteristics.

Question 14.
What do you understand by valley breeze?
Answer:
The valley breeze occurs during day time. Due to insolation, the valley bottom gets heated. The hot air becomes light and ascends towards the upper slopes. It is known as the valley breeze.

Fig. 10.3: Slopes heated by insolation

Atmospheric Circulation and Weather Systems Important Extra Questions Long Answer Type

Question 1.
Distinguish between:
1. planetary and periodic winds,
2. the sea breeze and land breeze.
Answer:
1. Planetary and periodic winds:
Planetary winds are related to the general circulatory pattern of winds on the rotating earth’s surface. These winds constitute the large-scale motion of the atmosphere under the influence of pressure gradients. They ignore seasonal heating and land-water contrast on the earth’s surface. They are also called permanent or primary wind system of the earth’s surface and comprise trade winds, westerlies, and polar easterlies. These winds blow constantly in a particular direction throughout the year.

Fig. 10.4: Planetary winds

The winds that change their direction periodically with the change in season are called periodic or secondary winds. Monsoon, air masses and fronts, cyclones and anticyclones, land and sea breezes, and mountain and valley breezes are the wind systems that periodically change their courses diurnally or seasonally.

2. Land and sea breezes:
Daily temperature contacts between land and water produce a small diurnal reversal of winds called land and sea breezes. Both are basically caused by differential heating of land and sea.

During the day, the land gets heated up much faster than the sea. The sea remains comparatively cool with higher pressure, so the sea breeze blows in from the sea to land during the day. Its speed is between 5-20 miles/hour and it is generally stronger in tropical than temperate regions.

Its influence does not normally exceed 15 miles from the coast. It is most deeply felt when one stands facing the sea in a coastal area.

At night, the reverse takes place. As the land cools down much faster than the sea, the cold and heavy air produces a region of local high pressure. The sea conserves its heat and remains quite warm. Its pressure is comparatively low. A land breeze thus blows out from land to sea.

Fishermen in the tropics often take advantage of the outgoing land breeze and sail out with it.

Question 2.
Describe the global pattern of the distribution of pressure.
Answer:
The horizontal distribution of pressure, or its global pattern in general, presents an alternate belt of low and high-pressure areas.

There is an inverse relationship between pressure and temperature. The equatorial region having high temperature has low pressure, while the polar regions with low temperature have high pressure. These pressure belts are thermally induced. Logically, there should have been a gradual increase in pressure from the equator towards the poles.

Fig. Pressure belts of the world (See fig.9.1)

There are two intermediate zones of subtropical highs in the vicinity of 30°N and S and two sub-polar lows in the vicinity of 60°N and S. The dynamic control, viz., pressure gradient force, rotation of the earth, are responsible for the formation of these pressure belts.

Thus there are seven pressure belts:

1. An equatorial trough of low pressure.
2. Sub-tropical high-pressure belt (Northern hemisphere)
3. Sub-polar low-pressure belt (Northern hemisphere)
4. Sub-polar low-pressure belt (Southern hemisphere)
5. Sub-tropical high-pressure belt (Southern hemisphere)
6. Polar high (Northern hemisphere)
7. Polar high (Southern hemisphere)

Question 3.
Discuss the seasonal variations in the pressure distribution over the earth’s surface.
Answer:
Despite a broad generalized pattern of pressure distribution on the earth, pressure conditions vary considerably on the basis of prevailing weather conditions in different parts of the world. The horizontal distribution of pressure on the earth’s surface is shown by isobar. Just as there is a daily range of temperature on the surface of tire earth, so there is the diurnal rhythm of pressure.

The direction and rate of change in pressure are called pressure gradient. It is at right angles to isobars, just as the slope of the land surface is at right angles to contour, lines. The rate of change or steepness of the gradient is shown by the spacing of isobars. Closely spacing isobars show’ steep pressure gradient, and widely spaced isobars show’ gentle gradient.

The zonal distribution of pressure is modified by continents and oceans, in summer, the relatively hot continents intensify the low-pressure cells and weaken or destroy high-pressure cells. In a similar manner, the corresponding cooler oceans weaken the low-pressure cells and the high-pressure cells. In winter the situation is reversed. ,

Fig. 10.6: Horizontal distribution of pressure and winds

Question 4.
What are cyclones? Describe the various types of cyclones.
Answer:
Cyclones constitute the most fundamental and climatically the most significant atmospheric disturbances affecting the weather. On the basis of the areas of their origin, they are classified into two types: temperate and tropical.

Temperate cyclones: Temperate1 cyclones are concentrated in the middle latitudes between 35° and 65° in both hemispheres. They are generally extensive having a vertical thickness ranging from 9 to 11 km. and a diameter of about 1,000 km. It is just like a spearhead, having the shape of an upturned ‘V’. The approaching temperate cyclones are noticed by the appearance of dark clouds in the background of white clouds.

According to polar front theory, the highs and lows of westerly wind belts result from the interactions and alteration of two contrasting types of air masses, one in the polar region and the other in the subtropics. Cold air from highs moves toward the equator and is deflected westward, forming the northeast and southeast polar winds. Warmer air from the subtropical highs moves toward the poles and by an eastward deflection from the westerly winds.

Fig. 10.7: Temperate cyclones

As soon as the cyclone approaches, there is drizzle followed by heavy rainfall. The velocity of the wind increases. On the approach of the warm front, the fall in the pressure stops, and the sky becomes clear. This gives the clue that the center of the cyclones has reached. Immediately after this, the temperature begins to fall and the sky becomes cloudy and raining again. This indicates the approach of a cold front.

Tropical cyclones: These are violent storms that originate over tropical seas and move over the coastal areas bringing about large-scale destruction caused by violent winds, very heavy rainfall, and storm surges. They are known as cyclones in the Indian ocean, hurricanes in the Atlantic, typhoons in the western Pacific and South China sea, and willy-willies in west Australia. The conditions favorable for the formation and intensification of tropical storms are:

• Large sea surface with a temperature higher than 27°C.
• Presence of the Coriolis force.
• Small variations in the vertical wind speed.
• A pre-existing weak low-pressure area or low level cyclonic
  circulation.
• Upper divergence above the sea level system.

The cyclone creates stone surges and they inundate the coastland. Over the Indian sea, the cyclonic storms occur in the pre-monsoon

Question 5.
Define and describe the fronts.
Answer:
The contact line between air masses of different properties is called a front. A cold front develops where the cold air mass moves under warm air mass and lifts it up. On the other hand, the trailing edge of a cold air mass that is followed by warm air is called a warm front. In each case, precipitation is likely to occur because warm air is rising over the cold air. Thus duration and intensity of precipitation along the few from.s are quite different. The cold front is steep and produces showery and sometimes violet precipitation for a longer period of time. If the cold front moves faster than the warm front in such a trap, part or all the pocket of warm air may be lifted from the surface, thus producing air occluded front. Often exculpation of the air masses lose earlier characters and form new fronts.

Here we are providing Class 11 Geography Important Extra Questions and Answers Chapter 9 Solar Radiation, Heat Balance and Temperature. Important Questions for Class 11 Geography are the best resource for students which helps in class 11 board exams.

Important Questions for Class 11 Geography Chapter 9 Solar Radiation, Heat Balance and Temperature

Solar Radiation, Heat Balance and Temperature Important Extra Questions Very Short Answer Type

Question 1.
What is insolation?
Answer:
The incoming solar radiation is called insolation.

Question 2.
How much energy radiated by the sun is intercepted by the earth?
Answer:
Only A of the billionth fraction of the energy radiated from the sun is intercepted by the earth.

Question 3.
What is isotherm?
Answer:
Isotherms are imaginary lines joining places having equal temperatures.

Question 4.
Where does the energy radiate from the sun come from?
Answer:
The energy radiated from the sun comes from nuclear reactions in its core.

Question 5.
What is the temperature at the core of the sun?
Answer:
The temperature at the core of sun-is about 15,000,000°C.

Question 6.
What is the radiant energy of sun commonly known as?
Answer:
The radiant energy of the sun is commonly known as short waves or electromagnetic waves.

Question 7.
At what speed the short waves travel?
Answer:
The short waves travel at a speed of light, i.e., about 2,98,000 km. per second.

Question 8.
What is terrestrial radiation?
Answer:
The longwave radiation, i.e., re-emittance of the energy received from the earth’s surface, is terrestrial radiation.

Question 9.
Name the processes which control the heat budget of the earth ., and the atmosphere.
Answer:
They are the processes of absorption, reflection and scattering.

Question 10.
Define heat budget.
Answer:
The gains and losses in heat by incoming and outgoing radiation is known as heat budget.

Question 11.
What is advection?
Answer:
Transfer of heat through the horizontal movement of the air is called advection.

Question 12.
What is meant by temperature gradient?
Answer:
The rate of change of temperature is called the temperature gradient.

Question 13.
Name two months of the year which represent the seasonal extremes of temperature.
Answer:
January and July months represent the seasonal extreme of temperature.

Question 14.
Define Planck’s law.
Answer:
Planck’s law states that hotter a body, the more energy it will ‘ radiate and shorter is the wavelength of that radiation.

Question 15.
What is specific heat?
Answer:
Specific heat is the energy needed to raise the temperature of one grain of a substance by one degree Celsius.

Question 16.
What is insolation?
Answer:
The incoming solar radiation is termed as insolation. It comes in the form of short waves.

Question 17.
What are the methods by which the atmosphere is heated?
Answer:
The atmosphere gets heated in the following ways:
(a) Radiation,
(b) Conduction,
(c) Convection,
(d) Advection.

Question 18.
Why do isotherms bend while crossing the continents and oceans?
Answer:
Due to differential heating and cooling of land and seawater.

Question 19.
How much energy radiated by the sun is intercepted by the earth?
Answer:
1/2000 million part of the total energy radiated by the sun is intercepted by the earth.

Question 20.
Which is the most important process of heating the atmosphere?
Answer:
Terrestrial radiation.

Question 21.
What is the temperature?
Answer:
Warmth or coolness of the air is called its temperature.

Question 22.
What is the extent of the Torrid Zone?
Answer:
23’/2°N to 23’/2°S.

Question 23.
What is the extent of the Frigid Zone?
Answer:
66V20 to poles.

Question 24.
Name the type of climate found in coastal areas.
Answer:
Maritime (moderate).

Question 25.
Why is the temperature of the earth increasing?
Answer:
Due to the increase in carbon dioxide.

Question 26.
What is insolation?
Answer:
The incoming solar radiation is termed as insolation.

Solar Radiation, Heat Balance and Temperature Important Extra Questions Short Answer Type

Question 1.
What is air drainage?
Answer:
The cold air acts almost like water and moves down the slope to pile up deeply in pockets and valley bottoms with warm air above. This is called air drainage. It protects plants from frost damages.

Question 2.
What are the characteristics of isotherms?
Answer:
Main characteristics of isotherms are:

1. Isotherms run along the latitudes.
2. Isotherms take sudden bends at the land-water edge because of land-water contact.
3. They are drawn at equal space which indicates the latitudinal thermal gradient.
4. Isotherms change their positions.

Question 3.
Discuss the variation in the distribution of insolation over the earth’s surface.
Answer:
The incoming solar radiation is called insolation. Insolation is * greatest at the equator. It decreases polewards. The total amount of insolation received at the equator is roughly about 4 times of that received at the poles. In tropical regions, the amount of insolation is only large but there is also little seasonal variation. It is because all their places between Tropic of Cancer and Capricorn experience overhead sun twice during the course of a year. Insolation is maximum twice in a belt between 23°30’ and 66°30′.

Question 4.
What are the effects of the atmosphere on insolation?
Answer:
The energy from the sun passes through different layers of the atmosphere before it reaches the ground. Atmospheric gases are essentially transparent to visible light, but suspended particles of liquid or solid material can absorb or reflect light. A thick cloud may allow less than 10% of sunlight to reach the earth’s surface. Clouds generally behave like mirrors. They reflect sunlight off in different directions rather than absorbing. Reflected sunlight is permanently lost from the earth. The blue colour of the daytime sky is due to the scattering of sunlight.

Question 5.
Define temperature.
Answer:
The temperature is the measurement of available or sensible heat energy in a system. It is a measure of hotness or coldness of the body. Such property determines whether the heat will flow out or into an object when it comes in contact with other objects.

Question 6.
Explain why the angle of the sun’s rays falls variably on different latitudes.
Answer:
The earth revolves around the sun once in a year in an elliptical path called the ‘plane of ecliptic’. At the same time, the earth rotates on its axis in 24 hours. The earth’s axis is tilted making an angle of 66°30′ from the plane. Due to inclination of the earth’s axis, the angle of the sun’s rays falling on the earth’s surface varies from vertical on the equator to more and more slanting as one moves towards the poles.

Question 7.
Explain how the ocean currents influence the temperature distribution over the earth surface.
Answer:
Ocean currents are large movements of ocean water from places of warm temperature to colder temperature or vice-versa. Their movement affects the temperature of the adjacent areas. The warm currents raise the temperature of adjoining colder landmasses. The climate of north-western Europe is modified to a large extent by ocean currents of the North Atlantic Ocean. The cold currents of the western coast of South Africa or South America lower the temperature of adjacent warmer lands.

Question 8.
What is the role played by prevailing winds in temperature modification?
Answer:
Prevailing winds also affect the temperature conditions of the areas. The moderating effects of oceans are brought to the adjacent lands through winds. On the contrary, off-shore winds take the effects of warm or cold currents away from the land.

Question 9.
What is the difference between direct radiation and diffused radiation?
Answer:
The sun emits short wave radiation to space and the earth’s surface. The solar energy strikes the upper limits of the atmosphere and it gradually reaches the earth’s surface directly or indirectly (scattered) and is absorbed. It is estimated that out of 100 units of incoming solar energy, 22 units travel directly to the earth’s surface. This energy flow is called direct radiation. Some of the scattered rays eventually also find their way down indirectly to the earth’s surface. They are collectively called diffused radiation.

Question 10.
What is global warming? What are its causes?
Answer:
The burning of fossil fuels, the cultivation of the soil, industrialisation of land on a large scale, rapid means of transport and deforestation have caused an imbalance in the atmosphere. These activities are increasing the amount of carbon dioxide. Thus, the greenhouse effect has raised the average temperature of the earth by 0,5°C. By the year 2000, the earth’s average temperature will go up by 2°C.

This is called global warming. It is causing a rise in the sea level due to melting of glaciers. It is threatening to submerge many coastal areas.

Question 11.
Why do different parallels receive different amounts of insolation?
Answer:
Due to the inclination of the earth’s axis, the angle of the sun’s rays falling on the earth’s surface varies from vertical on the equator to more and more slanting as one moves towards the poles. This latitudinal difference in the angle of incidence of sun’s rays leads to different amounts of insolation received at different parallels.

Fig.9.5: Incidence of the sun’s rays on the earth’s surface

Question 12.
How does the angle of the sun’s rays falling on the ground affect the amount of insolation?
Answer:
The amount of insolation reaching the earth’s surface depends largely on the inclination or angle of the sun’s rays. Vertical rays and those nearly 80 in the lower latitudes are more effective in increasing temperature than the oblique rays in the higher latitudes, although the duration of sunshine may be much longer in the latter case. Moreover, the oblique rays spread over a larger area on the earth’s surface whereas the vertical rays are concentrated over a smaller area, the intensity of heat being lighter in the area insolated by vertical rays.

Question 13.
Differentiate between advection and convection.
Answer:
Transfer of heat through the horizontal movement of the air is called advection, whereas the vertical mixing of the air is termed as convection. Convection is caused by the circulatory movement of the air itself and the pull of gravity.

Question 14.
Isotherms do not show the correct temperature of a place. Discuss.
Answer:
Isotherms show the temperature of a place supposing it to be at sea level. The temperature is reduced to sea level to avoid the effect of relief. Thus, isotherms do not show the actual temperature of a place.

Solar Radiation, Heat Balance and Temperature Important Extra Questions Long Answer Type

Question 1.
Discuss the impact of tilting of earth’s axis on insolation in the northern and southern hemisphere.
Answer:
The earth rotates on its axis in 24 hours. The earth’s axis is tilted at an angle of 66°30′ from the plane.

Fig.9.6 : Solstices and equinoxes

When the northern hemisphere is tilted towards the sun, it receives the maximum amount of insolation. On 21 st June, the sun is overhead the Tropic of Cancer and it is the longest day of the year for the northern hemisphere. All this time, the southern hemisphere is away from the sun and 21st June is the shortest day of the year for the southern hemisphere. On 21st March and 23rd September, the sun is over the equator and the length of the day is the same everywhere throughout the world. This position is called the equinox.

On 21st December, the southern hemisphere is in front of the sun and receives the maximum daylight. It is, however, the tropics that receive the maximum insolation.

Question 2.
Discuss the impact of altitude on temperature over the atmosphere.
Answer:
Altitude is the height of a point above mean sea level, measured vertically. The temperature decreases with increasing height and latitude from the earth’s surface. This vertical decrease in temperature takes place at the rate of 0.65° per 100 metres or 165 metres per 1°C. These variations are normal throughout the troposphere and are termed as normal lapse rate. The atmosphere near the surface is denser and contains a large amount of water vapour and dust particles. Being closer to the land surface, it absorbs more terrestrial heat than that of the upper air. Hence, the temperature is higher in the lower part of the atmosphere than in the upper part, where the air is cleaner. That is why the higher we go, the cooler it is. Ootacamund, Mount Abu, Panchmarhi are cooler in summer than plains.

Question 3.
What are the basic mechanisms of heat transfer? Discuss the importance of these mechanisms with reference to the atmosphere.
Answer:
There are three basic mechanisms of heat transfer:

1. Radiation,
2. Conduction, and
3. Convection.

1. Radiation: Radiation is the act of transmitting energy in the form of particles of electromagnetic waves. The process is similar to that of transmission of light from an electric bulb. There are two forms of radiations: solar radiation and terrestrial radiation. The atmosphere gets heated up, in fact, through terrestrial radiation and not by solar radiation.

2. Conduction: When two bodies of unequal temperatures are in contact with one another, there is a flow of energy in the form of heat from warmer to cooler body. The layer of air resting upon the warmer earth becomes heated by the process of conduction. The actual conduction during the course of the day affects only the lowest layer of the atmosphere.

3. Convection: Convection is the process of heat transfer caused by the dying circulatory movement of the fluid itself. It takes place due to difference in temperature, and hence in density, and the pull of gravity. Convection produces vertical movement. The horizontal movement of a similar nature is called advection.

Fig97: Convection circulation

A cyclic circulation helps in transforming the heat of lower layers to the upper layers of the atmosphere. This process of heating is convection.

Question 4.
How is the atmosphere heated? Discuss the role of terrestrial radiation in this process.
Answer:
The only source of heat for the earth or the atmosphere is the sun. But the sun does not heat the atmosphere directly. The solar radiation or energy emitted from the sun travels through space and reaches the earth’s surface in the form of insolation or incoming solar radiation. The incoming solar radiation has no significant role in heating the atmosphere. But it helps the earth’s surface. The earth, in turn, reradiates this energy in the form of terrestrial radiation.

Thus the earth functions as a transformer in an electric circuit, receiving energy in one state and transmitting it to another. The sun heats the earth and earth heats the atmosphere. Nearly 51 % of solar energy reaches the earth directly or indirectly. The sun emits short wave radiations to space. The earth, on the other hand, radiates it back in long waves. The terrestrial radiation warms up the layers of atmosphere above it by direct contact or through the transmission of heat by upward movement of air currents.

Fig.9.8: The annual radiation budget of the earth. Units are percentages of the total solar radiation received at the outer edge of the atmosphere.

Question 5.
How many shapes the sun has? Describe photosphere.
Answer:
The sun has three shapes: the core and the interior. The innermost portion of the sun is extremely hot and hence here hydrogen atoms combine to form a smaller number of heavier helium atoms. In this process, certain mass is converted into energy.

The Photosphere: Photosphere is the solar surface. The energy produced in the core reaches to this surface. Most of the sun’s energy comes from the photosphere and we see it as a solar disc. In the photosphere, there are granules that transport energy from the base of the photosphere to its surface. Sunspots are dark regions on the photospheres. They are formed due to strong magnetic fields. The energy is released in the form of x-ray and ultra-violet radiations from the sunspots.

Above the photosphere occurs the sun’s atmosphere. The lower part is chromosphere and the upper is the corona. They are visible only during solar eclipses. Corona exudes electromagnetic energy. These energy particles can be captured by earth’s magnetic field in the ionosphere and their interaction with gases produce the aurora.

Here we are providing Class 11 Geography Important Extra Questions and Answers Chapter 8 Composition and Structure of Atmosphere. Important Questions for Class 11 Geography are the best resource for students which helps in class 11 board exams.

Important Questions for Class 11 Geography Chapter 8 Composition and Structure of Atmosphere

Composition and Structure of Atmosphere Important Extra Questions Very Short Answer Type

Question 1.
How is the atmosphere held to the earth?
Answer:
The atmosphere is held to the earth by the force of gravity.

Question 2.
What is heterosphere?
Answer:
The layer of the atmosphere 90 km above the surface of the earth where the composition begins to change with a progressive increase in the lighter gases, is called heterosphere.

Question 3.
Which are the major constituents of clean dry air of atmosphere?
Answer:
Oxygen and nitrogen are the major constituents of clean dry air of the atmosphere.

Question 4.
Which gas of the atmosphere does not take part in a chemical reaction?
Answer:
‘Argon’ does not take part in a chemical reaction.

Question 5.
What are aerosols?
Answer:
Aerosols are huge amounts of s0lid and liquid particles present in the atmosphere.

Question 6.
Which gas despite its small percentage is crucial in atmospheric processes?
Answer:
Carbon dioxide is an important gas in the atmospheric processes.

Question 7.
What is the atmosphere?
Answer:
The atmosphere is a gaseous envelope extending thousands of kilometres above the earth’s surface.

Question 8.
What energises the atmosphere?
Answer:
The atmosphere is energised by the sun.

Question 9.
Where does much of life exist on the earth?
Answer:
Much of life exists at the bottom of the atmosphere where it meets the lithosphere and the hydrosphere.

Question 10.
Name two broad layers of the atmosphere.
Answer:
Homosphere and heterosphere are two broad layers of the atmosphere.

Question 11.
Name the three thermal layers of the homosphere.
Answer:
Troposphere, stratosphere and mesosphere.

Question 12.
What is wind?
Answer:
The horizontal motion of the air is known as wind.

Question 13.
Mention some forms of precipitation.
Answer:
Rain, hail, sleet or snow are some forms of precipitation.

Question 14.
Which gas acts as a filter and protects us from ultraviolet rays?
Answer:
Ozone gas protects us from the ultraviolet rays and acts as a filter.

Question 15.
Which layer transmits the radio waves?
Answer:
Ionosphere.

Question 16.
Name the gas which is found in the upper part of the atmosphere.
Answer:
Hydrogen.

Question 17.
What are the two causes of depletion of the ozone layer?
Answer:
Use of carbons and deforestation are the two causes of depletion of the ozone layer.

Question 18.
Name the gas which is most essential for life.
Answer:
Oxygen.

Question 19.
What are the principal elements of weather and climate?
Answer:
Temperature, pressure, wind, moisture and precipitation are the principal elements of weather and climate.

Question 20.
Why do the jet aircraft fly through the lower stratosphere?
Answer:
Because it provides the easiest flying conditions. It is the layer of calm and clean air. There is no water vapour and clouds are present.

Question 21.
What are the constituents of dust particles?
Answer:
Smoke-soot, ash, pollen are the main constituents of dust particles.

Question 22.
What is the weather?
Answer:
The cumulative effect of wind, temperature, pressure, clouds, humidity and precipitation is called weather.

Question 23.
What is the role of elements of weather?
Answer:
They influence temperature and precipitation.

Composition and Structure of Atmosphere Important Extra Questions Short Answer Type

Question 1.
Why are the vapour and dust particles important variables of weather and climate?
Answer:
The water vapour and dust particles are important variables of weather and climate because they are the source of all forms of condensation and principal absorbers of heat received from the sun or radiated from the earth. Besides, they affect the stability of the atmosphere.

Question 2.
What is meant by a normal lapse rate?
Answer:
The temperature decreases with altitude because the atmosphere is heated more by the heat radiated from the earth’s surface. Wanner air lying under the cooler air goes up or turns downward. In this layer, the temperature decreases vertically at a rate of 0.65°C per 100 metres. It is called the normal lapse rate.

Question 3.
What is homosphere?
Answer:
The atmospheric layer up to an altitude of 90 km. above the surface of the earth is generally called homosphere. It is uniform in term of these major gases – nitrogen, oxygen and argon. In addition, it also contains some rare gases like neon, krypton and xenon.

Question 4.
Name the gases and other materials which compose the atmosphere.
Answer:
Nitrogen, oxygen and argon are the most important gases of the atmosphere. In addition, it contains gases like carbon dioxide, neon, helium, ozone, hydrogen, methane, krypton and xenon. Besides, there are also present huge amounts of solid and liquid particles collectively called aerosols.

Question 5.
Discuss the properties of nitrogen gas.
Answer:
Nitrogen is the most abundant gas of the atmosphere. By volume, it constitutes 78.8% of the total gases present in the atmosphere. Nitrogen does not easily enter into chemical union with other substances but gets fixed into the soil. It serves mainly as diluent or dissolver. It regulates combustion.

Question 6.
What is the importance of carbon dioxide on the earth?
Answer:
By volume carbon dioxide constitutes 0.03% of the total gases of the earth’s atmosphere. Although it forms a small portion, it is an important gas in the atmospheric processes. It can absorb the heat and thus allows the lower atmosphere to be warmed up by heat radiation coming from the sun and from the earth’s surface. Green plants in the process of photosynthesis utilise carbon dioxide from the atmosphere.

Question 7.
Explain the difference between weather and climate.
Answer:
The weather of any place is the sum total of its temperature, pressure, winds, moisture and precipitation conditions for a short period of time. Climate, on the other hand, is the composite weather conditions over a considerable period of time.

Question 8.
Identify the climatic controls.
Answer:
The various climatic controls are given below :

1. Latitude or sun.
2. Distribution of land and water
3. The great semi-permanent high and low-pressure belts
4. Winds
5. Altitude
6. Mountain barriers
7. Ocean currents
8. Storms of various kinds

Question 9.
What is the importance of the atmosphere for the earth?
Answer:
The earth is the only known planet to have life. The atmosphere, which is unlike that of any other planet, encircles and protects the earth. Changes in the composition of the atmosphere are closely associated with the evolution of the earth. One of the most important transition was the increase in oxygen when photosynthetic plants evolved.

The atmosphere is a mixture of gases, the largest proportion of which is nitrogen. However, the most important is oxygen, without which life could not be sustained. The very survival of life processes is associated with the atmosphere.

The influence of the atmosphere on humans particularly is not only direct but also indirect through natural vegetation, soil and topography.

Question 10.
What is tropopause?
Answer:
The tropopause is the plane which separates the troposphere and stratosphere. It is the boundary between these two layers. It is a thin transitional zone between two layers.

Question 11.
Explain three major features of the troposphere.
Answer:
Three major features are :

1. It is 16 km thick at the equator and 10 km thick at the poles.
2. The temperature decreases with the altitude at the rate of l°C per 165 metres.
3. Biological activities take place in this layer.

Question 12.
What are the main characteristics of the lowermost layer of the atmosphere?
Answer:
The lowermost layer is the troposphere.

• Its average height is 16-18 km.
• All biological activities occur in this layer.
• All the atmospheric processes take place in this layer.
• It is 16 km thick at the equator and 10 km thick at the poles.

Composition and Structure of Atmosphere Important Extra Questions Long Answer Type

Question 1.
Distinguish between troposphere and stratosphere.
Answer:

Troposphere	Stratosphere
(1) It is the lowermost layer of the atmosphere.	(1) It is the second layer of the atmosphere above the earth.
(2) Its height varies from 10-18 km. at the equator.	(2) Its height is up to 50 km.
(3) Temperature decreases at the rate of 1 °C per 165 metres in this layer.	(3) In this layer temperature is very low and fairly constant.
(4) It is the zone of convection currents of the atmosphere.	(4) It is a zone of non-convection currents of the atmosphere.
(5) Water vapour, dust particles, clouds are found in this layer.	(5) There is no water vapour but dust particles and clouds are found.
(6) Atmospheric processes occur in this layer.	(6) This zone is free from atmospheric disturbances.

Question 2.
What is the difference between condensation and precipitation?
Answer:
Condensation is the physical process of the transition of a substance from the vapour to the liquid state, e.g., as a result of cooling or increase of pressure. It occurs in the atmosphere when the air is saturated or when it is cool. Thus, the change of state of the moisture from invisible water vapour to visible liquid (water) or solid (ice or snow ) state is known n as condensation. It is opposite of evaporation.

Precipitation, on the other hand, means ‘throwing down of moisture’. Continuous condensation in the body of the air helps the water droplets to grow in size so that the resistance of the air fails to keep them suspended. In such cases, only an ascending air current can keep them floating in the air. In the absence of such a current, the products of condensation begin to fall on the earth’s surface. The process whereby the water vapour first condenses in the air and then falls on to the earth is called precipitation.

Question 3.
Discuss the principal elements of weather and climate and the major climatic controls.
Answer:
The principal elements of weather and climate are temperature precipitation, moisture, pressure and winds. These are called elements because they are the ingredients out of which various weather and climate types are compounded. The temperature and precipitation are the main basic elements to which pressure, winds and other elements are related.

Temperature expresses the intensity of heat. Practically all the heat energy on the earth is the result of insulation or the increasing solar radiation. Unequal distribution of temperature over the earth’s surface causes differences in atmospheric pressure, which causes winds.

Higher the temperature, the greater is the capacity’ of air to hold moisture on cooling. The air is not able to retain all the moisture it gathers while warm. This leads to condensation and precipitation.

Thus, the temperature is the basic element on which other elements of climate depend.

The climatic controls are :
Latitude (or sun), distribution of land and water, the great semi¬permanent high and low-pressure belts, winds, altitude, mountain barriers, ocean currents and storms of various kinds.

Question 4.
Define the atmosphere. Explain its importance to human life.
Answer:
The atmosphere is a mixture of air and various gases which envelopes the earth all around. It represents the gaseous realm of the earth. It is held to the earth by the force of gravity.

Importance of atmosphere:

1. It contains gases like oxygen (essential for breathing) for man and animals and carbon dioxide for plants.
2. By trapping the heat, it acts as a greenhouse. It keeps the earth
   warm.
3. One of its layer, the ionosphere, reflects radio waves back to the earth and makes radio communication possible.
4. It protects us from the deadly cosmic rays and meteors which are continuously showered on the earth from outer space.
5. All the weather phenomenon take place in the atmosphere. Presence of water vapour in the atmosphere brings many changes such as condensation and precipitation. These processes influence the human life, plants and animals.
6. It absorbs ultraviolet rays.
7. It acts as an air conditioner by moderating the extremes of heat ‘ and cold.
8. It is a storehouse of water vapour.

Question 5.
Discuss the proportion of the constituent gases of the atmosphere.
Answer:
The atmosphere is a mixture of various gases. It includes :
Nitrogen (N,), Oxygen (O,), Argon (Ar), Carbon dioxide (CO,), Neon (Ne), Helium (He), Ozone (O,), Hydrogen (H), Methane (CH4), Krypton (Kr) and Xenon (Xe).

Nitrogen (N2): It is a colourless, odourless gas, the main constituent (i.e. 78.8% by volume) of the atmosphere. It is an essential constituent of living organisms. It is an important element for plants.

Oxygen (O,): Constitutes 20.94% of the total volume of the atmosphere. It is the second most abundant gas. It is essential to plant and animal life.

Argon (Ar): It constitutes one per cent volume of the total atmosphere. It is an inert gas, does not take part in any chemical reaction.

Carbon dioxide: It constitutes a very small amount (0.03%). It is an important gas in the atmospheric process. It can absorb heat and thus allows the lower atmosphere to be warmed up by heat radiation from the sun and from the earth’s surface. Green plants in the process of photosynthesis utilise carbon dioxide from the atmosphere.

Neon (Ne): Neon is an inert gaseous element occurring in’ trivial quantities (0.0018%) in the atmosphere.

Helium (He): It exists primarily in the sun’s atmosphere. It is an inert element of the atmosphere.

Ozone (03): It is an allotropic form of oxygen (02). Its main concentration lies between 20 to 25 km. from the earth’s surface.

Hydrogen (H): It is the lightest element. It is gaseous and inflammable. It is used in many chemical processes.

Here we are providing Class 11 Geography Important Extra Questions and Answers Chapter 7 Landforms and their Evolution. Important Questions for Class 11 Geography are the best resource for students which helps in class 11 board exams.

Important Questions for Class 11 Geography Chapter 7 Landforms and their Evolution

Landforms and their Evolution Important Extra Questions Very Short Answer Type

Question 1.
What is geomorphology?
Answer:
It is the study of landforms especially concerned with the genesis, evolution, and processes involved in the formation of the surface features of the earth.

Question 2.
What is the relief?
Answer:
The physical landscape of the earth’s surface is called relief. It includes mountains, valleys, plains, and plateaus.

Question 3.
Name various types of weathering.
Answer:
Chemical weathering, mechanical weathering, and biological weathering.

Question 4.
Arrange the following from smaller to bigger form: stream, gully, river, rill.
Answer:
Rill, gully, stream, river.

Question 5.
What is fiord?
Answer:
When a glacial trough formed near the sea gets filled up by the seawater, it is called a fiord. It is a deep steep-sided water inlet near the sea.

Question 6.
What do you understand by mud-flow?
Answer:
Mud-flow is a moving mass of solid waste fluid by rain or melting snow.

Question 7.
What is deflation?
Answer:
Deflation is the lifting and transporting of loose particles of clay and silt, collectively referred to as dust.

Question 8.
What is a landform?
Answer:
The landform is the shape, focus and volume of a specific physical feature of the earth’s surface produced by natural processes of erosion and deposition.

Question 9.
What is the combination?
Answer:
A combination is a form of chemical weathering caused due to the reaction of minerals with dissolved carbon dioxide in water.

Question 10.
Name two basic forms in which the running water acts as a geomorphic agent.
Answer:
As a geomorphic agent, the running water acts in two basic forms, namely overland flow and channel or streamflow.

Question 11.
What is a drainage basin?
Answer:
The drainage basin is a part of land drained by a sole river system.

Question 12.
What are three closely inter-related geomorphic works performed by rivers?
Answer:
Rivers perform three closely inter-related geomorphic works, viz., erosion, transportation, and deposition.

Question 13.
Give an example of badland topography.
Answer:
The valley of the Chambal in Madhya Pradesh is an example of badland topography.

Question 14.
What is Karst topography?
Answer:
Karst topography is a landscape formed by groundwater in a limestond1 region.

Question 15.
What is meant by water table?
Answer:
The top of the zone of saturated rocks is called the water table.

Question 16.
Why is wind action most prominent in arid and semi-arid areas?
Answer:
Wind action is most prominent in arid and semi-arid areas as there are loose particles of soil in these areas and wind can remove them easily.

Question 17.
Which areas on the earth’s surface depict landforms made by glaciers?
Answer:
The following areas on the earth’s surface depict landforms made by glaciers:

1. High altitude areas,
2. High mountain areas.

Question 18.
What is a glacier?
Answer:
The moving heap of ice and snow is termed a glacier.

Question 19.
How are lagoons formed? Give two examples of lagoons from India.
Answer:
Lagoons are formed when sand bars along the coast cut off a portion of the sea from the main water body. Example:

1. Chilka lake (in Orissa),
2. Pullicat lake (Tamilnadu).

Question 20.
Where are areas of permanent snow or ice found over the surface of the earth?
Answer:

1. Areas or regions situated at high latitudes.
2. Areas situated at very high altitudes irrespective of their distance from the equator.

Question 21.
What acts as cutting tools for the sea waves?
Answer:
Loose pieces of rocks and sand suspended in the sea waves.

Question 22.
What is marine erosion?
Answer:
Marine erosion is the erosion of rocks in the coastal areas, carried out by the sea waves.

Question 23.
Where are lagoons mostly found in India?
Answer:
On the Malabar coast of India.

Question 24.
Where is the Marine beach situated in India?
Answer:
Marine beach is situated in Chennai on the Coromandel coast.

Question 25.
What is the distance covered by a rapidly moving glacier in a day?
Answer:
4 kilometres per day.

Question 26.
Where is wind most important as an agent of gradation?
Answer:
In arid and semi-arid regions.

Question 27.
Enumerate various forms made by wind action.
Answer:

1. Wind eroded basin,
2. Loess plains,
3. Sand dunes.

Question 28.
Where do the sand dunes originate?
Answer:
Sand dunes originate at the place where there is some obstruction in the way of the wind.

Landforms and their Evolution Important Extra Questions Short Answer Type

Question 1.
How would you explain the fact that the areas of permanent snow or ice are in high latitudes and very high altitudes?
Answer:

1. Sun always shines perpendicular on the equator. Hence, equatorial regions get intense heat due to straight sun rays. As we go northwards or southwards from the equator, the sun’s rays become oblique and less heat is received in these regions. Hence, poles are always cold.
2. Temperature decreases with increase in height at the rate of 1 °C per 165 metres height. Hence, as we go above from the equator, fewer temperatures are observed. A height comes when the temperature is below freezing point and snow and ice rules over.

Question 2.
What are snowfields? Where are they generally situated?
Answer:
The vast areas which are permanently covered with snow and ice are called snowfields.

The snowfields are generally found situated above the snow line.

1. High latitudes and polar regions,
2. Near mountain tops.

Question 3.
What is meant by ‘moraines’?
Answer:
Glaciers carry pieces of rocks, big and small, with them. They deposit them at certain places – at their edges, on the bottom, at the terminals and the central zone of two glaciers. These deposits are called moraines.

Question 4.
Define loess plateau?
Answer:
Loess is the deposit of sand blown over long distances and deposited over large areas. When the thickness of the loess is hundreds of metres, it assumes the name of loess plateau.

Question 5.
Write a short note on the formation of sand dunes.
Answer:
Wind deposits sand brought by it as sand dunes. The major features of these sand dunes are as follows:

1. A sand dune is a typical hill. It has a crest.
2. It is generally mobile as it goes on shifting along the direction of the prevailing wind.
3. Obstructions in the path of the wind lead to the formation of the sand dunes.
4. Sand dunes vary in size. They vary from a few metres to 300 metres in height.

Question 6.
Distinguish between stalactite and stalagmite.
Answer:

Stalactite	Stalagmite
Deposits of lime hanging downwards from the ceiling are of a cave are called stalactites	deposits of lime taking place upwards from the floor of an ave are termed as stalagmites.

Question 7.
Distinguish between beaches and sand bars.
Answer:

Beaches	Sand Bars
(1) Beaches. are deposits of sand and gravel along the coast.	(1) Sand bars are embank¬ments of sand and gravel built by the wave action on the seafloor at a short distance from the coast,
(2) Example: Marine beach in Chennai.	(2) Example: Sand bars along the coast of Kerala.

Question 8.
What is a fiord?
Answer:
When a glacial trough formed near the sea gets filled up by the seawater, it is called a fiord. Thus a fiord is a deep, steep-sided water inlet near the sea. It is typical of Norwegian and Chilean coasts.

Question 9.
What is ‘regolith’?
Answer:
Regolith is a layer of loose or soft material lying above the bedrock. When regolith is formed by decomposition and disintegration of the bedrock that lies directly beneath it, it is called residual regolith. The regolith transported by steam, ice, water and deposited elsewhere is called transported regolith.

Question 10.
Define fluvial denudation.
Answer:
Running water is undoubtedly the most important agent of denudation. It is most conspicuous as a stream or river that transports enormous volumes of surplus precipitation from the land to the ocean. Stream action, in combination with weathering, mass wasting and overland flow, is responsible for the total process called fluvial denudation.

Question 11.
Explain two forms of the flow of running water as the geomorphic agent.
Answer:
Running water acts as a geomorphic agent in two basic forms, viz., overland flow and channel or streamflow.

Overland flow is the movement of run-off downhill on the ground surface in a more or less broadly distributed sheet or film. Second is channel flow or streamflow in which water moves to lower levels in a long, narrow, trough-like feature called stream-channel, bounded on both sides by rising shapes called banks that contain the flow.

Question 12.
Discuss the features developed due to falling rain on bare surfaces.
Answer:
Gentle rain falling on bare surfaces loosens the soil and muddies the water. The muddy water flows as the thin, slow-moving surface layer of water called sheet flow. As the slope increases, the water scours additional sediments and erodes small channels, which are called rills. Headward erosion of rills and their subsequent widening leads to gully formation. Gullies dissect the land into a number of isolated hills, giving rise to badland topography.

Question 13.
Discuss the internal and external forces involved in the creation of landforms.
Answer:
A host of internal and external forces are involved in the creation of landforms. Tectonic forces crumple rocks and push up continents and mountain ranges. Moving water, air and ice erode rocks and transport the eroded debris to depositional sites and thus change the appearance of the landscape with the passage of time. The intensity of these agencies varies from one region to- another depending on climate, vegetation and altitude.

Question 14.
How is a U-shaped valley formed?
Answer:
A glacier does not make its own valley. When a glacier enters a V-shaped river valley, it modifies it into a U-shaped valley. The valley is deepened as the pressure of ice increases. A wide, flat structure is formed. Due to side cutting the valley is widened, and it is known as U-shaped valley.

Question 15.
On what factors the erosional work of the river depends?
Answer:
The erosional work of the river depends upon the following factors:

1. Volume of water
2. The slope of the river
3. Load of the river
4. Velocity of water
5. The nature of the rocks

Landforms and their Evolution Important Extra Questions Long Answer Type

Question 1.
Discuss features created by wave action.
Answer:
At the shoreline, the line along which the water meets the land, the major erosive agent is wave action. Along the coast of hard rock, a gently inclined rock surface is carved out to accommodate the swash and backwash. It is called abrasion platform. A shoreline rising abruptly from the abrasion platform is called a marine cliff. The stormy waves thrust rock fragments with great violence against the cliff base to develop wave-cut notches or sea-caves. Relatively thick and gently sloping accumulation of sand, gravel or cobbles in the zone of breakers and surf is called beads.

Question 2.
Write an essay on the geomorphic work of rivers,
Answer:
Rivers are the stream channels organised into branching channel network. Rivers perform three closely interacted geomorphic works, viz.,

1. erosion,
2. transportation,
3. deposition. River erosion is the progressive removal of minerals from the surface of stream channel which itself may consist of the bedrock of regolith. River transportation is the movement of eroded particles in a chemical solution, in turbulent suspension or 6y rolling and changing along the bed. River deposition consists of -accumulation of any transported particles on the stream bed on the adjoining flood plain or on the floor of a body of standing water into which the river empties. While the river performs all three functions simultaneously, one may dominate over the other in different parts of the river course.

The nature of river erosion depends upon the materials of which the channel is composed. Erosion is hydraulic action, the pressure and drag of flowing water exerted upon grains projecting from the bed and banks. Weak bedrock and various forms of regolith are easily carved out by hydraulic action. Abrasion occurs when rock particles carried in the current strike against the exposed bedrock of the channel. Small particles are reduced by crushing and grinding when caught between larger cobbles and boulders. The chemical reaction between ions carried in solution and exposed mineral surfaces result in a form of erosion called a solution.

Question 3.
How does wind affect rocks and what kinds of rocks are eroded the fastest? Explain the formation of landforms by winds.
Answer:
Winds are not strong enough to remove the mineral matter from hard rocks, moist clay or soil rich in vegetation. They can only affect those rocks which are soft, arid and vegetation less. Hence rocks which are soft are eroded the fastest.

Formation of landforms by winds: Winds form landforms both during erosional and depositional work.

Erosional landforms – Winds erode loose particles of soil and take them away. In course of a time, a hollow is formed in the desert surface. This is called a wind-eroded basin.

Depositional landforms – When the wind becomes weak and some obstacle lies in its path, deposition of transported loose particles begin to take place. Wind becomes weak due to the decrease in its velocity. As a result of the depositions, sand dunes are formed. They are of different types and shapes.

Question 4.
Which is the most important agent modifying the coastal topography? Describe the various features formed by this agent of gradation.
Answer:
The most important agent modifying coastal topography is sea waves. Sea waves erode, transport and deposit debris in the coastal regions and form both erosional as well as depositional features,

Erosional Features: Arches and Sea stacks: If the rock formation along the coast differs in resistance, softer rocks are eroded and harder remain to stand. This results in the formation of arches and stacks.

Depositional Features:

1. Sea waves deposit sand, gravel and pebbles on the shore. These deposits are called beaches. Marine beach (Triplicane) in Chennai is famous in India.
2. Sometimes sea waves deposit embankments of sand and gravel on the seafloor not far from the coast. These embankments are termed as bars. Very often ships strike against these bars and cause damage to themselves.
3. Sometimes sand bars separate a portion of the sea from the main sea, giving birth to a lake lagoon. A lagoon is a saltwater .lake. These lakes have a connection with the main sea through sand and gravel along with the narrow outlets. Malabar coast in India abounds in lagoons. On the eastern coast, Chilka (in Orissa) and Pullicat (near Chennai) are two well-known lagoons.

Question 5.
Distinguish between:
1. V-shaped valley and U-shaped valley.
2. Valley glacier and Continental glacier.
3. Gorge and Canyon.
Answer:
1. V-shaped valley and U-shaped valley.

V-shaped valley	U-shaped valley
(1) Valley with slanting sides and the narrow bottom is called a V-shaped valley.	(1) Valley with steep sides and flat bottom is called a U-shaped valley.
(2) It is formed by the action of running water.	(2) It is formed by the action of the glacier.
(3) Example: Ganga, Brahmputra valley.	(3) Valley formed by Pindari glacier in the Himalayas.

2. Valley glacier and Continental glacier.

Valley glacier	Continental glacier
(1) Glaciers formed in the high mountains are long and narrow as they occupy former river valley, and are termed as valley glacier.	(1) Glaciers formed in polar and arctic regions over extensive areas are called continental glaciers.
(2) Example: Siachen glacier.	(2) Example: Antarctic glacier.

3. Gorge and Canyon.

Gorge	Canyon
(1) A gorge is a narrow deep opening of the river across a mountain.	(1) Canyon are formed in dry areas.
(2) Side cuttings are absent due to hard rocks.	(2) It has high vertical walls for long distances.
(3) The river’s downcutting leads to the formation of deep gorges	(3) The upper part of the canyon is wide due to weathering.
	(4) The lower part is deeper due to rapid downcutting

Here we are providing Class 11 Geography Important Extra Questions and Answers Chapter 6 Geomorphic Processes. Important Questions for Class 11 Geography are the best resource for students which helps in class 11 board exams.

Important Questions for Class 11 Geography Chapter 6 Geomorphic Processes

Geomorphic Processes Important Extra Questions Very Short Answer Type

Question 1.
What are exogenetic forces?
Answer:
The external forces are known as exogenetic forces.

Question 2.
What are endogenetic forces?
Answer:
The internal forces operating from within the earth are known as endogenetic forces.

Question 3.
What is the degradation?
Answer:
The wearing down of relief is known as degradation.

Question 4.
What is the function of endogenetic forces?
Answer:
These forces continuously elevate or build up parts of the earth’s surface.

Question 5.
Name the various exogenetic elements.
Answer:
Water, air wind, ice, etc. are exogenetic elements.

Question 6.
How is energy generated within the earth?
Answer:
The energy within the earth is generated by radioactivity, rotational and tidal friction.

Question 7.
What is the effect of gravitational stresses?
Answer:
They activate wave and tide induced currents and winds.

Question 8.
What is orogeny?
Answer:
Orogeny is a mountain building process.

Question 9.
What causes earthquakes?
Answer:
Orogeny, epeirogeny, plate tectonics cause earthquakes.

Question 10.
Name the denudation processes.
Answer:
Weathering, mass wasting/movements, erosion and transportation are the denudation processes.

Question 11.
Name the different types of weathering.
Answer:
Weathering is of three types:-

1. Chemical,
2. Physical,
3. Biological weathering.

Question 12.
What are the important agents of weathering?
Answer:
Frost, wind, heat, glacier and running water.

Question 13.
Name the two active factors of soil formation.
Answer:
Climate and living organisms.

Question 14.
What do you mean by exfoliation?
Answer:
It is the process of peeling off the outer layers from the main rock.

Question 15.
What is bad land?
Answer:
An area dissected with gullies and ravines.

Question 16.
What is humus?
Answer:
Humus is the organic matter of vegetable or animal organs in the soil.

Question 17.
How do organic soils develop?
Answer:
Organic soils develop from the accumulation of plant residues that are preserved by the low oxygen environment of shallow and stagnant waters.

Question 18.
Name the primary factors responsible for the development of soils.
Answer:
The primary factors responsible for the development of soils are parent material, climate, biota, topography and time.

Question 19.
What is eutrophication?
Answer:
Enrichment of water with nutrients, primarily phosphorous, causing abundant aquatic plant growth is called eutrophication.

Question 20.
Define soil profile.
Answer:
A vertical section of the soil through all its horizons and extending into the parent material is called a soil profile.

Question 21.
What is pedology?
Answer:
The branch of science that deals with the study of soil are called pedology.

Question 22.
What is added to the saline soil to reduce its salinity?
Answer:
Gypsum is added to the saline soil to reduce its salinity and make it useful for crops.

Question 23.
What are the mineral contents of laterites?
Answer:
The mineral contents of laterites include aluminium and iron oxide,

Question 24.
What makes the soil alkaline?
Answer:
Alkaline soils are formed in areas of low rainfall due to the accumulation or retention of lime.

Question 25.
Name the four soil-forming processes.
Answer:
The four soil-forming processes are eluviation, illuviation, Teaching and chelation.

Question 26.
What does ICAR stand for?
Answer:
ICAR stands for Indian Council of Agricultural Research.

Question 27.
Name eight soil groups as classified by ICAR.
Answer:
They are alluvial soils, black soils, red and yellow soils, laterite, arid, saline, peaty, organic and forest soils.

Geomorphic Processes Important Extra Questions Short Answer Type

Question 1.
What are geomorphic processes? Describe briefly.
Answer:
The endogenetic and exogenetic forces causing physical; stresses and chemical actions on earth materials and bringing about changes in the configuration of the earth’s surface are known as geomorphic processes. Diastrophism and volcanism are endogenetic geomorphic processes.

Question 2.
Distinguish between exogenetic and endogenetic forces.
Answer:
Exogenetic forces: The earth’s surface is being continuously subjected to external forces induced basically by the energy (sun). These external forces are known as exogenetic forces.

Endogenetic forces: The forces originating within the earth from its interior are known as endogenic forces. They are responsible for building up and wearing down of the earth’s surface.

Question 3.
What is directional force and what is its role?
Answer:
Gravity is a directional force. It activates the movements of matter and also causes stresses on the earth materials. Indirect gravitational stresses activate wave and tide induced currents and winds. Without gravity and gradients, there would be no mobility and hence no erosion.

Question 4.
What do you understand by oxidation?
Answer:
When atmospheric oxygen combines with minerals of rocks (especially with iron) to form oxides, the process is known as oxidation, v Rocks get rusted due to the presence of air and water. The rocks begin to decay and crumble to a powder mass of brown dust.

Question 5.
What is carbonation?
Answer:
Carbonation is the process in which rainwater gets mixed with carbon dioxide. It dissolves limestone, chalk and marble rock to form carbonates or bicarbonates with minerals. Calcium carbonates and magnesium carbonates are dissolved in carbonic acid.

Question 6.
What is weathering?
Answer:
Weathering means the weakening or wearing down, breaking up, rotting and disintegration of rocks at or over the earth’s surface.

Question 7.
What is chemical weathering?
Answer:
Chemical weathering is the decomposition of rocks by chemical methods. It results from the action of weak acids and gases like oxygen, carbon dioxide and hydrogen. Chemical weathering produces a chemical change in the minerals of rocks. High temperatures and humidity cause the rocks to decompose.

Question 8.
How does mass wasting take place?
Answer:
The force of gravity acts constantly upon the soil and bedrock. At various places, the internal strength of these materials is sufficient to keep them in place. But when the ground surface is sloping, the force of gravity is directed down the slope parallel with the surface. Every particle has least same tendency to roll or slide downhill and will do so whenever the downslope force exceeds the resisting forces of friction and cohesion that tend to bind the particles to the rest of the mass.

Question 9.
How does biota help in soil development?
Answer:
Biota is the collective term for the animal and plant life of a specific area as per the period of time. The decomposition of organic wastes and residues and the activities of living plants and animals have marked influence on soil development. Burrowing animals such as moles, prairie dogs, earthworms, ants and termites help soil development slowly by decomposing organic matter and forming weak acids that dissolve minerals faster. The roots of living plants and decomposed plant material release weak organic acids that help in weathering and soil development.

Question 10.
What is the pH value of soils?
Answer:
‘pH’ value means ‘potential hydrogen’, the standard measure of activity or Alkalimists in the soils. It is based on the activity of hydrogen ions in a litre of a solution, expressed in gram per litre. The pH value range from 0 to 14.0. Neutrality is at 3.0. Numbers lower than neutrality signify increasing acidity and higher numbers increasing salinity. Knowledge of the pH value of the soil under cultivation is most important in agriculture and horticulture.

Question 11.
What is saline soil?
Answer:
Because of the dry climate and poor drainage conditions, this soil acquires more salt. It is widespread in western Gujarat (Rann of Kutch), deltas of the east coast and Sunderban areas of West Bengal. Gypsum diminishes the salinity of soil and makes it useful for drops.

Question 12.
Distinguish between chelation and leaching.
Answer:
Leaching is the downward movement of material from a soil horizon in solution.

Chelation is also the downward movement of material, similar to leaching, but under the influence of organic complex compounds.

Question 13.
Discuss the role of topography in soil formation.
Answer:
The topography influences the soil formation through its relationship with relief, water and temperature. Steep hillsides have thin soil cover because of surface runoff that results in the erosion of the surface. On the other hand, gentle hillside preserves appreciable soil overdue to the luxuriant vegetation and sufficient water passing in vertically to deeper levels. The land-locked depressions receive a high amount of runoff water that favours appreciable vegetation cover but slower decomposition because of oxidation deficiency. This results in the formation of soil that is rich in organic matter.

Question 14.
How many essential elements are required by plants?
Answer:
Plants need at least 16 essential elements. They are carbon, hydrogen, oxygen, phosphorus, potassium, nitrogen, sulphur, calcium, iron, magnesium, boron, manganese, copper, zinc, molybdenum and chlorine.

Question 15.
How are the exogenetic earth processes driven?
Answer:
Exogenetic earth processes are the external processes that are driven by solar energy. They act through the atmosphere and oceans where air and water come in contact with the lithosphere.

Geomorphic Processes Important Extra Questions Long Answer Type

Question 1.
What is the rock weathering? Discuss various ways in which it takes place.
Answer:
Rock weathering is the chemical decomposition and physical disintegration of rocks. Weathering takes place in three ways :

1. Chemical weathering
2. Physical or mechanical weathering
3. Biological action

1. Chemical weathering: Chemical weathering is the decomposition of rocks by chemical methods. It results from the action of weak acids and gases like oxygen, carbon dioxide and hydrogen. Chemical weathering produces a chemical change in the minerals of rocks. High temperatures and humidity cause the rocks to decompose.

2. Physical or Mechanical weathering: The physical wear and tear of rocks is called mechanical weathering. In the middle and high latitude climates, and at high altitudes, alternate freezing and melting of water called frost action provide a powerful mechanism for breaking up of rocks. Water that penetrates joint planes and other natural openings in the rock expands when transformed into ice crystals. The pressure of the growing mass of such crystals causes joint blocks to be heaved up and pried free of the parent mass.

In the dry climates of low and middle latitudes, an important agent of rock disintegration is salt. The dry climates have long droughts in which evaporation can occur continuously causing water deep in the rock to be drawn surfaceward by capillary force. Near the rock surface, the moisture steadily evaporates permitting dissolved salts to be deposited in the opening of the rock. The growing salt crystals in this manner are capable of exerting pressure and disintegrating rocks.

The action of roots of growing plants exerting pressure upon the confining walls of rocks is yet another kind of mechanical weathering.

Biological weathering: When the breakdown of rocks and minerals is due to plants, animals and bacteria, it is called biological weathering. The main contribution of animals to weathering seems to be repeated mixing of soil material, thus bringing fresh material into exposure to the weathering agents. Snails are common in lime-rich ) areas and can wear deep holes in the limestone. Bird droppings may provide ‘ organic matter for the slant of soil formation and weathering.

Grazing by large animals loosens the soil, thus increasing surface runoff and soil erosion. Larger plants affect weathering in a number of ways. Cracks may be widened by root pressure. The accumulation of elements by plants and their return to the surface of the soil affects the nature of the soil and weathering profiles and the course of weathering. , Vegetation litter and decaying vegetation are important in conserving moisture which in turn enhances weathering.

Question 2.
Describe the geomorphic processes and how the gravity force affects the materials.
Answer:
The endogenetic and exogenetic forces causing physical stresses and chemical action on earth materials and bringing about changes in the configuration of the surface of the earth are known as geomorphic processes. The common geomorphic processes are diastrophism, volcanism, weathering, mass wasting, erosion and deposition.

Any exogenetic element of nature (like ice, wind, water, etc.) capable of acquiring and transporting earth materials can be called a geomorphic agent. When these elements become mobile due to gradients, they remove the materials and transport them over slopes. An agent is a mobile medium which removes, transports and deposits ‘ earth materials. Running water, groundwater, glaciers, wind, waves and currents, etc. can be called geomorphic agents.

Gravity is a directional force activating all downslope movements of matter and also causes stresses on the earth materials. Gravitational stresses activate wave and tide induced currents and winds. Without p gravity and gradients, there would be no mobility and hence no erosion, transportation and deposition are possible. So, the gravitational stresses are as important as the other geomorphic processes. Gravity force keeps us in contact with the surface and switches on the movement of all surface earth materials.

Question 3.
Write short notes on:-
1. Diastrophism,
2. Volcanism,
3. Exfoliation.
Answer:
1. Diastrophism: These are endogenetic processes. They include

1. orogenic processes, involving mountain building through severe folding and affecting long and Harrow belts of earth’s crust,
2. Epeirogenic processes, involving uplift or warping of large parts of the earth’s crust,
3. earthquakes, involving local, relatively minor movement, and
4. plate tectonics, involving horizontal movements of the crustal plates. In the process of orogeny, the crust is severely deformed into folds. Due to Epeirogency, there may be simple deformation. Orogeny is a mountain building process, whereas epeirogeny is a continental building process. Through the processes of orogeny, epeirogeny earthquakes and plate tectonics, there can be faulting and fracturing of the crust. All these processes cause pressure, volume and temperature (PVT) changes which in turn induce metamorphism of rocks.

2. Volcanism: Volcanism includes the movement of molten rocks towards the surface of the earth and also the formation of many intrusive and extrusive volcanic forms. In the process of volcanism, a host of landforms are created, including rock deformation, resulting in Domal folds and metamorphism of surrounding rocks due to intense heat.

3. Exfoliation: This is a type of physical weathering process unloading, thermal contraction and expansion and salt weathering. Exfoliation is a result and not a process. Spalling or flaking off of more or less curved sheets of shells from rocks or bedrocks resalts in smooth and rounded surfaces. Exfoliation can occur due to expansion and contraction induced by unloading and temperature changes. Exfoliation domes and tors result due to unloading and thermal expansion respectively. Granular exfoliation or disintegration, taking place especially due to salt weathering processes, also results in smooth and rounded surfaces.

Question 4.
Define and describe soil horizons.
Answer:
Soil horizons are the soil layers that are approximately parallel to the soil surface. Each horizon is different from the other. Boundaries between horizons range from indistinct to abrupt and clear. Horizons are formed because of differences in the degree of depth, amounts of humus accumulated, translocation of colloids by water and loss of colloids. Capital letters A, B, C, D and E are used to designate these horizons.

Horizons are commonly identified from the surface downwards.

‘A’ horizon is the topsoil containing humus, from which materials are washed downwards by percolating water (leaching) so that it is termed an eluvial (eluviation) horizon.

‘B’ horizon or sub-soil lies beneath ‘A’ horizon. It is a horizon of deposition, of secondary enrichment, an illuvial horizon (illuviation) into which are deposited, the washed-out materials from ‘A’ horizon. Underneath is the ‘C’ horizon, it is the weathered parent material of the existing soil. Some soil scientists also distinguish ‘D’ horizon, the bedrock.

Question 5.
Discuss the factors responsible for soil formation and also the processes involved.
Answer:
Soil forming factors: There are five factors that influence soil formation, viz., parent material, climate, biota, topography and time.
1. Parent material: Parent material in soil science is weathered bedrock or the transported glacial or alluvial material. Soils from weakly cemented sandstone will be sandy and soils from shales will be shallow and fine-textured. Similarly, clay formation is favoured more by a high percentage of decomposable dark mineral and less by quartz.

2. Climate: Climate is an important active factor in soil formation. Several processes are involved in soil formation and may to some extent affect the soil profile.

3. Biota: Biota is the collective term for the animal and plant life of a
a specific area as per the period of time. The decomposition of organic wastes and residues and the activities of living plants and animals have marked influence on soil development. Burrowing animals such as moles, prairie dogs, earthworms, ants and termites help soil development slowly by decomposing organic matter and forming weak acids that dissolve minerals faster. The roots of living plants and decomposed plant material release weak organic acids that help in weathering and soil development.

4. Topography: Topography means relief features. Steep hillsides have thin soil cover because of surface runoff that results in the erosion of the surface. On the other hand, gentle hillside preserves appreciable soil cover due to the luxuriant vegetation and sufficient water passing in vertically to deeper levels. The landlocked depressions receive a high amount of runoff water that favours appreciable vegetation cover but slower decomposition because of oxidation deficiency. This results in the formation of soil that is rich in organic water. Thus, topography influences soil formation through its relationship with water and temperature.

5. Time: Soil formation is a very slow process. It may take a few hundred to a few thousand years. This period of time, however, varies from place to place, depending upon other factors discussed above (plant material, -biota, topography, climate). Under ideal conditions, a recognisable soil profile may develop in 200 years and under less favourable circumstances, it may extend to several thousand years.

Soil, forming processes: Several processes are involved in soil formation. These are:

1. Eluviation: It is the mechanical translocation of clay or other fine particles down the profile.
2. Illuviation: ft is the accumulation of the washed down material in the lower horizons of the soil profile.
3. Leaching: It is the removal and downward movement of material from a horizon in solution.
4. Cheluviation: It is a downward movement of the material, similar to leaching, but under the influence of complex organic compounds.

Here we are providing Class 11 Geography Important Extra Questions and Answers Chapter 5 Minerals and Rocks. Important Questions for Class 11 Geography are the best resource for students which helps in class 11 board exams.

Important Questions for Class 11 Geography Chapter 5 Minerals and Rocks

Minerals and Rocks Important Extra Questions Very Short Answer Type

Question 1.
What is meant by smelting?
Answer:
The process through which metals are separated from ores by using heat is called smelting.

Question 2.
Why are coal and petroleum called fossil fuels?
Answer:
Because they are associated with fossils (remnants of organisms).

Question 3.
Name two important sources of atomic energy found in India.
Answer:
Uranium and Thorium.

Question 4.
Define a rock.
Answer:
A rock is any natural mass of mineral matter that makes up the earth’s crust.

Question 5.
Name the types of rocks.
Answer:
The three types of rocks are the igneous rocks, the sedimentary rocks and the metamorphic rocks. ‘

Question 6.
Which are two main types of igneous rocks?
Answer:
On the basis of chemical differentiation of magma, there are two types of igneous rocks, viz., mafic and felsic.

Question 7.
What is meant by ‘texture? of the rocks?
Answer:
Texture relates to the sizes and patterns of the mineral crystals present in the rock.

Question 8.
Name the scale that grades between the size of mineral grains.
Answer:
The system of grading of mineral grains according to their size is called the Wentworth scale.

Question 9.
What is ‘phenocrysts’?
Answer:
Few large crystals embedded in a matrix of smaller crystals are known as phenocrysts.

Question 10.
What is ‘diagenesis’?
Answer:
It is the process of physical and chemical changes affecting sediments during their conversion into solid rocks.

Question 11.
What is the scientific study of rocks called?
Answer:
The scientific study of rocks is called petrology.

Question 12.
What does the term ‘lithosphere’ mean?
Answer:
The term lithosphere means a sphere of rocks.

Question 13.
Give two examples of soft rocks.
Answer:
Clay and chalk.

Question 14.
What kind of rock is granite?
Answer:
Granite is a coarse-grained igneous rock that is formed by the slow cooling of magma.

Question 15.
What happens to clay when it gets metamorphosed?
Answer:
It converts into slate.

Question 16.
What is metamorphism?
Answer:
Metamorphism is the change of form. It refers to the change in the form of rock when it is subjected to heat or pressure.

Question 17.
How many minerals have been identified and named till date?
Answer:
At least 2000 minerals have been named and identified till date.

Question 18.
Name the largest diamond ever found.
Answer:
Cullinan diamond is the largest diamond ever found.

Question 19.
What is the basic source of all minerals found in the earth?
Answer:
The basic source of all minerals is the hot magma in the interior of the earth.

Question 20.
What are ‘optical properties’ of minerals?
Answer:
Optical means ‘usual’. The optical properties of minerals are evaluated by means of a microscope using polarised light rays.

Question 21.
What are sedimentary rocks?
Answer:
The rocks which are formed by the accumulation of sediments are called sedimentary rocks.

Question 22.
Name three types of sedimentary rocks on the basis of their mode of formation.
Answer:

1. Mechanically formed,
2. Organically formed,
3. Chemically formed.

Question 23.
Name the different types of coal.
Answer:
Peat, Lignite, Bituminus and Anthracite.

Question 24.
What is the thickness of lithosphere?
Answer:
The thickness of the lithosphere is about 100 km.

Question 25.
What are schists?
Answer:
Strongly developed foliation is known as schists.

Minerals and Rocks Important Extra Questions Short Answer Type

Question 1.
What is lithification?
Answer:
The fragments of the rocks are transported by various exogenous agencies and deposited. These deposits through compaction and/or cementation turn into rocks. This process is called lithification. In many sedimentary rocks, the layers of deposits. retain their characteristics even after lithification.

Question 2.
How would you classify the igneous rocks based on the size and nature of crystals?
Answer:
There are five types of igneous rocks based on the size and nature of crystals viz.

1. rocks with phaneritic textured crystals
2. rocks with orphan textured crystals
3. equigranular textured rocks, and
4. porphyritic textured rocks.

The crystals large enough to be seen with naked eyes or with the help of hand lens are called phaneritic textured crystals, whereas those too small to be distinguished without the aid of a microscope are – called orphan textured crystals of the igneous rocks. Where crystals in the rocks are all within the same size range, the texture is described as equigranular, whereas few large crystals are embedded in a matrix of smaller crystals, the texture is porphyritic.

Question 3.
Discuss the classification of sedimentary rocks into clastic and non-clastic division.
Answer:
Clastic means ‘broken’, describes clastic sediments consisting of particles removed individually from a parent rock source. The naming of clastic rocks depends on the size of component mineral grains.

The non-clastic sedimentary rocks are made of sediments of two basic types: chemical precipitates and organically derived sediments.

The chemical precipitates are solid mineral matters precipitated from an aqueous solution. The rock salt and gypsum are its examples. The organically derived sediments consist of remains of plants and animals as well as mineral matters produced by activities of plants and animals. Coal and limestone are examples.

Question 4.
What are schists?
Answer:
As metamorphism continues a large percentage of the minerals assume the plate-like shape and are assembled in parallel orientation in the rock, a structure is known as foliation. Strongly developed foliation is known as schist.

Question 5.
What is meant by mineral hardness?
Answer:
The degree to which a mineral surface resists being scratched is known as its mineral hardness. Hardness is important because it determines how a mineral is worn away by the abrasive action of stream, waves, wind and glaciers in the processes of erosion and transportation.

Question 6.
What are minerals and how are they formed?
Answer:
The mineral is a naturally occurring homogeneous solid that is an inorganic substance having an orderly atomic structure and definite chemical composition.

The basic source of all minerals is hot magma in the interior of the earth. When magma cools, crystals of mineral appear. These first crystals may sink in the magma so that the composition of the magma changes with depth. Thus, a sequence of minerals is formed in the rocks as the magma cools. Besides this, certain minerals such as coal, petroleum and natural gas are organic substances found in solid, liquid and gaseous forms respectively.

Question 7.
Describe the formation of sedimentary rocks.
Answer:
Sedimentary rocks are made from sediments deposited by the erosion and weathering of other rocks. Wind, water and snow erode rocks and carry the sediments to low lying areas. When deposited in the sea, they are compressed and hardened to form layers of rocks. Sediment is a fragmented mineral and organic matter derived directly or indirectly from pre-existing rocks and from life processes transported and deposited by air, water, etc. Chalk, sandstone, limestone, gypsum and coal are the examples.

Question 8.
What is mineral ‘lustre’?
Answer:
The appearance of a mineral surface under reflected light is referred to as its mineral lustre. It is described by several descriptive adjectives, such as metallic (metal like), adamantine (diamond), vitreous glass), resinous (oil), pearly or silky.

Question 9.
What do you understand by the specific gravity of minerals?
Answer:
Each mineral has a certain specific gravity. The specific gravity is the ratio of its density to the density of water at 4° Celsius. Mineral’s specific gravity is a property of great importance because it determines the density of a given rock and rock density, in turn, determines the gross layered structure of the earth.

Question 10.
What is the Deccan Trap?
Answer:
The Deccan trap is an extensive area in the north-west part of India. It covers about 5 lakh sq. km, area. It has been formed by lava flows. Lava has solidified to form basalt. It is useful for cotton cultivation.

Question 11.
How is coal formed?
Answer:
Vegetation is hurried in swamps and forests. Due to pressure of the overlying sediments, the remains of plants are changed into carbon. Coal is formed in this way. Coal is of different types such as peat, lignite, bituminous and anthracite.

Question 12.
What are the three types of rocks? Give two examples of each of them.
Answer:
The three types of rocks are:

1. Igneous rocks
2. Sedimentary rocks
3. Metamorphic rocks

1. Igneous rocks: These rocks are formed by the cooling and solidification of molten lava and magma in the interior of the earth. Granite and basalt are examples.

2. Sedimentary rocks: These rocks have been formed by the deposition cementation of the fragments by exogenous means, i.e., wind, ice and sea. Examples are – sandstone and clay.

3. Metamorphic rocks: These rocks are formed by the change in colour, hardness, texture and mineral composition of the pre-existing rocks. Examples are – marble, slate.

Question 13.
What is meant by the texture of rocks?
Answer:
The texture means the size and pattern of the mineral crystals present in the rock. The size of the mineral crystals in an igneous rock depends largely upon the rate of cooling of magma.

Question 14.
Why fossils are preserved in sedimentary and not in igneous rocks?
Answer:
Sedimentary rocks are formed by the deposition of fragments ‘ carried away by exogenous means. They are deposited in distinct strata or layers. Fossils in the form of prints of leaves, insects or soft bovine animals and pieces of bones, shells or some hard parts of old living beings are embedded into layers of the sedimentary rocks. Thus, fossils are preserved in sedimentary rocks. The igneous rocks are formed by the solidification of magma. They are massive. They have no layers. Therefore, fossils cannot be preserved in igneous hard rocks and they are fossils-free.

Minerals and Rocks Important Extra Questions Long Answer Type

Question 1.
Write short notes on:
1. Sedimentary rocks
2. Types of metamorphism
Answer:
1. Sedimentary rocks: Exogenous agencies such as rain, wind, ice, running water, plants and animals are constantly hurried in rock disintegration producing loose and broken rock fragments in all sizes. These minerals are carried by wind, ice and running water in depressions such as lakes and seas on the earth’s surface. Such dropped materials are called sediments. Accumulation of these sediments in course of time gives rise to sedimentary rocks. The word ‘sedimentary’ is derived from the Latin word ‘sedimented’ means setting down. The sediments are usually deposited in distinct layers or strata. Therefore, these rocks are also known as stratified rocks.

2. Types of metamorphism: Metamorphism is the process of transformation of pre-existing rock into a new rock. Thus, metamorphic rocks are found when a rock is subjected to heat and/or pressure. Their characteristics are altered by forming new mineral forms. There are three types of metamorphism, viz. foliation, lineation and banding. When, under continued metamorphism, its minerals assume the plate-like shape and are assembled in parallel orientation in the rock, it is called foliation, e.g., Schist is formed in this manner.

When the mineral grains are drawn out into long, thin, pencil-like objects, all in parallel alignment, it is referred to as lineation. In another type of metamorphism, i.e., banding, the minerals of different varieties or groups are segregated into alternate layers. These layers are usually of light or dark shades, making the banding conspicuous.

Question 2.
What is the economic importance of minerals?
Answer:
Mineral resources can be divided into four main groups – essential resources, energy resources, metal resources and industrial resources. The most basic group, essential resources, comprises soil and water. Energy resources can be divided into fossil fuels (crude oil, natural gas, coal, oil shale and tar sand) and nuclear fuels (uranium, thorium and geothermal power). Metal resources range from structural metals such as iron, aluminium and titanium to ornamental and industrial metals such as gold, platinum and gallium.

Mineral deposits have two geological characteristics that make them a real challenge to modem civilization. First, all of them are non-renewable resources. The geological processes that form them are much slower than the rate at which we exploit them. There is no likelihood of our ability to grow mineral deposits at a rate equal to our consumption. Second, mineral deposits have a place value. We cannot decide from where to extract them; nature made that decision for us when the deposits were formed.

Question 3.
Describe the categorization of metamorphic rocks.
Answer:
The metamorphic rocks can be broadly grouped into two major classes – cataclastic rocks and recrystallised rocks. Cataclastic rocks are formed by mechanical disruption (breaking and crushing) of the original materials. The process is described as dynamic metamorphism.

The recrystallised rocks are further divided into two sub-classes – contact and regional metamorphic rocks. The contact metamorphic rocks are formed by recrystallisation under high temperature caused by intruding magma. The rocks are not subjected to bending or breaking and new minerals emanating from magma are added to metamorphosed rocks. The regional metamorphic rocks undergo recrystallisation during the process of being deformed by sharing often under the condition of high pressure or high temperature or bolts.

Question 4.
Discuss various types of rocks in detail.
Answer:
There are three main groups of rocks: igneous, sedimentary and metamorphic rocks.
Igneous rocks: These are formed from lava hurled out of a volcano or from the cooling of hot magma below the crust. Granite is a coarse-grained rock that was formed by the slow cooling of magma. Basalt is a fine-grained igneous rock, almost black, that was formed by quick cooling of lava. Chemical differentiation of magma gives rise to mafic and felsic types of igneous rocks.

The size of mineral crystals in an igneous rock largely depends upon the rate of cooling of magma. As a general rule, rapid cooling results in small crystals and slow cooling in large crystals. Extremely sudden cooling results in the formation of a natural glass which is non-crystalline. Large bodies of magma trapped beneath the surface cool very slowly because the surrounding rocks conduct the heat slowly. Rapid cooling occurs in lava that loses heat rapidly to the atmosphere or to the overlying ocean water.

Question 5.
Describe the formation of igneous rocks, giving suitable examples of various types.
Answer:
The igneous rocks are divided into extrusive rocks and intrusive rocks. When the magma solidifies on the surface of the earth, we call it an extrusive rock. A typical example of this kind of rock is basalt. It is a very fine-grained rock, usually Sf black in colour.

On the other hand, when the magma solidifies in the crust, below the surface, it is called an intrusive rock. The few most common examples of intrusive rocks are granite and dolerite. More frequent, however, is the solidification of magma below the earth’s surface leading to the formation of intrusive rocks. Igneous rocks are classified on the basis of chemical composition and texture. Chemical differentiation of magma gives rise to mafic and felsic types of igneous rocks.

Texture relates to the sizes and pattern of the mineral crystals present in the rock. The size of mineral crystals in an igneous rock depends largely upon the rate of cooling of magma. As a general rule, rapid cooling results in small crystals and slow cooling results in large crystals. Extremely sudden cooling results in the formation of natural glass which is non-crystalline. Large bodies of magma trapped beneath the surface cool very slowly because the surrounding rocks conduct the heat slowly. Rapid cooling occurs in lava that loses heat rapidly to the atmosphere or to the overlying ocean water.

Here we are providing Class 11 Geography Important Extra Questions and Answers Chapter 13 Water (Oceans). Important Questions for Class 11 Geography are the best resource for students which helps in class 11 board exams.

Important Questions for Class 11 Geography Chapter 13 Water (Oceans)

Water (Oceans) Important Extra Questions Very Short Answer Type

Question 1.
What are brines?
Answer:
Brines are salt solutions commonly containing a higher portion of dissolved salt than that occurring in seawater.

Question 2.
How would you classify the large water bodies?
Answer:
The large water bodies can be classified into four groups, viz., oceans, intercontinental seas, enclosed seas and fringing seas.

Question 3.
Name four major oceans of the earth.
Answer:
The four major oceans of the earth are the Pacific Ocean, Atlantic Ocean, Indian Ocean and the Arctic Ocean.

Question 4.
Give three examples of intercontinental seas.
Answer:
They are Malays Sea, Central American Sea and the Mediterranean Sea.

Question 5.
Give a few examples of enclosed seas.
Answer:
Baltic Sea, Red Sea, Hudson Bay and the Persian Gulf are some examples of enclosed seas.

Question 6.
Identify some fringing seas.
Answer:
Baring Sea, Japan Sea, East China Sea, Andaman, California, North Sea, Laurentian Sea, Bass Sea, English Channel and Irish Seas.

Question 7.
What are the factors on which the amount of rainfall entering the soil depends?
Answer:
The amount of rainfall entering the soil depends upon the rate of rainfall and the infiltration rate of the soil.

Question 8.
What are the first order relief features of the earth?
Answer:
Continents and ocean basins are the first order relief features of the earth.

Question 9.
“The continental margins consists of two major submarine features.” Name them.
Answer:
They are the continental shelf and the continental slope.

Question 10.
Mention three types of features of the ocean basin floor.
Answer:
The ocean basin floor contains three types of features, viz.,

1. abyssal plains and hills,
2. oceanic rise and
3. seamounts.

Question 11.
Name the second layer of oceans identified on the basis of their temperature structure.
Answer:
It is Theraseoline.

Question 12.
What is the major salt presents in the seawater?
Answer:
The major salt present in seawater is sodium chloride.

Question 13.
Name the deepest part of the ocean.
Answer:
The deepest part of the ocean is the Mariana Trench in the Pacific Ocean. It is from 11,034 m. deep below the sea level.

Question 14.
Where is the tallest sea mount situated?
Answer:
The tallest seamount is situated between Samoa and New Zealand which is 8690 m. high from the surrounding ocean floor.

Question 15.
What are the factors determining the salinity of seawater?
Answer:
The salinity of seawater depends upon the extent of evaporation, river discharge and precipitation.

Question 16.
What is residence time?
Answer:
The average time that an element remains dissolved in the ocean before removal is known as residence time.

Question 17.
How do you measure the salinity of seawater?
Answer:
It is measured in gm. of salt per thousand gm of seawater.

Question 18.
Why is the earth called Blue planet?
Answer:
Because of the abundance of water on its surface, the earth is often called a Blue planet.

Question 19.
What are oceanic deeps?
Answer:
Trough like depressions or trenches in the seafloor is called oceanic deeps. Deeps occur mostly at the convergence of plates in subduction zones.

Question 20.
How is the hydrological cycle expressed mathematically?
Answer:
The hydrological cycle is expressed mathematically as:

RF = RO + ET

RF includes all types of precipitations, RO is round off and ET is evapotranspiration.

Question 21.
Which is the largest ocean in the world?
Answer:
The Pacific Ocean.

Question 22.
Which sea has the maximum salinity?
Answer:
Dead Sea – 238 per thousand.

Question 23.
How much part of the earth is covered by the Pacific Ocean?
Answer:
1/3 part.

Question 24.
How much percentage of the earth is covered with water?
Answer:
71 % of the surface of the earth is covered with water.

Question 25.
What is the average salinity of ocean water?
Answer:
35 per thousand.

Question 26.
Name the two main banks of the world.
Answer:

1. The Duggar bank,
2. The Grand bank,

Question 27.
What percentage of the ocean floor is covered by the continental shelf?
Answer:
7.6%.

Water (Oceans) Important Extra Questions Short Answer Type

Question 1.
Why is earth called the ‘Blue Planet’?
Answer:
The earth is called a Blue planet because of the abundance of water found on the surface of the earth. Water covers 71 % of the earth surface.

If we take into account only the water surface of the earth, then 43% lies in the northern hemisphere and 57% in the southern hemisphere.

Question 2.
What are oceanic deeps?
Answer:
The oceanic deeps are deeper than the abyssal plains. They occupy 2% of the oceanic area. Although deeps are found in the Pacific ocean. Mariana deep is the deepest deep in the Pacific Ocean.

Question 3.
Name the most common features found on the ocean floor.
Answer:
The most common features found on the ocean floor are:

1. Continental shelf
2. Continental slope
3. Submarine canyon
4. Abyssal plains
5. Submarine ridge
6. Ocean deeps
7. Troughs

Question 4.
Define the continental shelf.
Answer:
From the coasts towards the open sea, there often exists a stretch of the shallow sea. The bed of this shallow sea bordering the continental platform is known as the continental shelf. It is a continuation of the continental block submerged below the sea. It slopes gently towards the sea, the angle of slope usually being less than one degree. The depth of the shallow seas rushing over a continental shelf varies from low tide to about 100 fathoms. Along the eastern coast of India, there exists a fairly wide strip of the continental shelf.

Question 5.
What are oceanic deeps?
Answer:
Trough like depressions or trenches in the seafloor is called oceanic deeps. Deeps occur mostly at the convergence of plates in subduction zones.

Question 6.
What are seamounts?
Answer:
Seamounts are topographical features rising from the ocean floor. A seamount is an isolated peak, usually a volcano, with a pointed summit, usually lies below the ocean surface, sometimes 3000 m. below.

Question 7.
What is an abyssal plain?
Answer:
Abyssal plain is a deep-sea plain. It is a very large and relatively level area of the ocean floor, covered with a thin layer of sediment. Thus abyssal plain is an area of the deep ocean floor having a flat bottom with a very’ faint slope. Characteristically situated at the foot of the continental rise, the abyssal plain is present in all ocean basins. It is formed by long-continued deposition of very’ fine sediments and, therefore, has a nearly perfect flatness.

Question 8.
Write a short note on the continental rise.
Answer:
Continental rise is a submarine feature of the continental margins. Along its seaward margin, the continental shelf gives way to the continental slope. The slope is abruptly replaced by the continental rise. Continental rise is a surface of much gentler slope decreasing in steepness toward the ocean basin floor. It generally has a moderate to low relief.

Question 9.
What is runoff? How does it occur?
Answer:
Runoff is th§ water flowing from a drainage area. It is that part of precipitation which run off the land surface into streams. Runoff occurs when precipitation, that does not have an opportunity to infiltrate into the soil, flows across the land surface. However, most of it enters the stream channel ultimately, which carries it to the oceans. A part of precipitation that infiltrates the soil percolates downward to the water table through springs. Broadly speaking, runoff is composed of water from both surface flow and seepage flow. It is an extremely important-segment of hydrological cycles.

Question 10.
Discuss the factors affecting the distribution of temperature of the ocean water.
Answer:
The salinity of seawater varies from place to place. At the equator, the salinity is somewhat lower due to abundant rains, greater cloudiness and low rate of evaporation. In latitudes about 20° in both the hemispheres, where evaporation is more intense and precipitation is lower, salinity is greater and in the temperate latitudes, where evaporation is less and rains. are more abundant, salinity is lower.

In Red sea, where no river flows, the salinity is 40 to 41 per thousand. In the Black sea, in which numerous rivers discharge, the salinity is 17 to 18 per thousand. In the White sea. it is between 25 and 26 per thousand, while in the Baltic sea it is 3 to 4 per thousand on an average.

Fig. 13.4: Distribution of surface water salinity in oceans

Question 11.
Why is the seawater saline?
Answer:
The seawater is saline because a number of salts are dissolved in it. The total weight of salts dissolved in the sea is 4800 million tonnes. Of these, sodium chloride, or common salt, accounts for 3800 million tonnes, sulphate for 3000 million tonnes, magnesium for 1600 million tonnes, potassium for 480 million tonnes and bromide for 83 million tonnes. The seawater may be less saline or more saline depending upon the extent of evaporation, river discharge and precipitation, but salt composition remains invariable.

Question 12.
What are the direct and indirect uses of oceans to man?
Answer:
Oceans are directly or indirectly useful to man in many ways:
Direct uses of the oceans:

1. Oceans are the storehouse of fishes.
2. They are a storehouse of minerals.
3. They provide the cheapest route for transportation.

Indirect uses: Indirectly-oceans control the climate.

Question 13.
How is the depth of seafloor measured?
Answer:
The depth of seafloor is measured with sound waves. A depth recorder is used for this purpose. The echo of the sound returning after striking the sea bottom forms the basis of it. It helps to measure the velocity and depth.

Question 14.
What do you understand by hydrosphere?
Answer:
The hydrosphere is the part of the earth submerged by oceans and seas. The vast oceans cover a total area of about 71% of the total earth’s surface. Earth is called a blue planet. Approximately 61% of the northern hemisphere and 81 % of the southern hemisphere is known as water hemisphere. The distribution of land and water is antipolar on earth. The Arctic Ocean surrounds the north pole and the Antarctic continent encircles the south pole.

Water (Oceans) Important Extra Questions Long Answer Type

Question 1.
Prepare a map of the Atlantic Ocean floor, mentioning ocean basins and mid-Atlantic ridges.
Answer:
The Atlantic Ocean covers about one-sixth of the earth’s area. Resembling ‘S’ in shape, the ocean is bounded on the west by North America and South America, and On the east by Europe and Africa. To the south, it extends up to Antarctica and in the north, it is bounded by Greenland and Iceland.

The mid-Atlantic ridge, running from north to south in ‘S’ form is about 14,450 km. long and about 4000 m. high. The ridge has a broad fracture in the middle and slopes on both sides gently. The mid-oceanic ridge in the North Atlantic is known as Dolphin Ridge, and that in the South Atlant ic as the Challenger Ridge. A number of islands are located on the ridge.

The mid-Atlantic ridge divides the ocean into two major basins, namely, the East and West Atlantic basins. Some other basins in the Atlantic are the North American basin, The Labrador basin, The Brazil basin. The Argentina, Agulhas, Angola, and the West.

Fig. 13.3: Major Relief features of the Atlantic Ocean

Question 2.
What type of relief features exists in the ocean basin floor?
Answer:
The ocean basin is an extensive region of the basin floor, generally lying at a depth ranging between 2,500 and 6,000 m. It covers about 76.2% of the ocean’s area.

The ocean basin floor contains three types of relief features:

1. abyssal plains and hills,
2. oceanic rise and
3. seamounts.

An abyssal plain is an area of the deep ocean floor having a flat bottom with a very faint slope. Characteristically situated at the foot of the continental rise, the abyssal plain is present in all ocean basins. Abyssal plains are surfaces formed by long-continued deposition of very fine sediments and, therefore, have a nearly perfect flatness. Abyssal hills are small hills rising to heights of a few tens of metres to a few hundred metres above the sea basin floor.

The ocean rise is an area hundreds of km. in the breadth over which the surface rises several hundred metres above the surrounding abyssal plain. Within the rise, the relief may range from subdued to very rugged.

Seamounts are the isolated peaks that rise 1000 ms. or more above the seafloor. Many of the seamounts are conspicuously flat-topped and extremely steep riched, named guyot.

Question 3.
Identify various layers of the ocean based on the level of salinity.
Answer:
The salinity of the water is the ratio of the total weight of dissolved
solids to the weight of water. It is variable in quantity, differentiating in value from place to place over the oceans and at various depths. The average salinity is 35 per thousand. The relationship of salinity to depth is analogous with the three-layer temperature systems.

1. First and the topmost layer is the shallow surface layer of high salinity (35.0 to 36.5 per thousand)
2. Below this layer is a zone of the rapid decrease in salinity, called a halocline. It corresponds with the thermocline.
3. Below the halocline, differences in salinity’ are very small and salinity lies in the range of 34.6 to 34.9 per thousand for most of the ocean body. Thus, the salinity decreases with the increasing depth.

Question 4.
Discuss the longitudinal variation in the salinity of ocean water.
Answer:
The salinity of seawater varies from place to place. At the equator, the salinity is somewhat lower due to abundant rains, greater cloudiness and low rate of evaporation. In latitudes about 20° in both the hemispheres, where evaporation is more intense and precipitation is lower, salinity is greater and in the temperate latitudes, where evaporation is less and rains. are more abundant, salinity is lower.

In Red sea, where no river flows, the salinity is 40 to 41 per thousand. In the Black sea, in which numerous rivers discharge, the salinity is 17 to 18 per thousand. In the White sea. it is between 25 and 26 per thousand, while in the Baltic sea it is 3 to 4 per thousand on an average.

Fig. 13.4: Distribution of surface water salinity in oceans

Question 5.
Describe the hydrological cycle in brief.
Answer:
The hydrological cycle is the continuous circulation of water from the earth’s surface to the atmosphere. Water from the oceans is evaporated and lifted into the atmosphere. It is eventually condensed and is returned back to the earth’s surface in the form of rain, hail, snow or sleet.

Some of the precipitation, after wetting the foliage and ground, runs off over the surface to the streams. It is the water that sometimes causes erosion and is the main contribution to floods. Of the precipitation that soaks into the ground, some are available for growing plants and for evaporation. Some reach the deeper zones and percolates through springs and seeps to maintain streams during the dry period. The streams, in turn, eventually return the water back to the oceans where it originated. It is because of this never-ending circulation that the process has come to be known as the hydrological cycle.

The hydrological cycle is mathematically expressed as:

RF = RO + ET, where RF-includes all types of precipitation, RO is runoff and ET is evapotranspiration.

Runoff occurs when precipitation, that does not have an opportunity to infiltrate into soil, flows across the land surface. However, most of it enters the stream channel ultimately, which carries it to the oceans. A part of precipitation that infiltrates the soil percolates downward to the water table through springs. Broadly speaking, runoff is composed of water from both surface flow and seepage flow. It is an extremely important segment of the hydrological cycle. Rainwater that reaches the soil surface is wholly or partly absorbed by the soil in the process of infiltration. The amount of rainfall entering the soil depends upon the s* rate of rainfall and infiltration rate of the soil.

Here we are providing Class 11 Geography Important Extra Questions and Answers Chapter 12 World Climate and Climate Change. Important Questions for Class 11 Geography are the best resource for students which helps in class 11 board exams.

Important Questions for Class 11 Geography Chapter 12 World Climate and Climate Change

World Climate and Climate Change Important Extra Questions Very Short Answer Type

Question 1.
What is a climatic region?
Answer:
A climatic region is defined as an area on the earth’s surface, where an approximately homogenous set of climatic conditions is produced by the combined effect of climatic groups.

Question 2.
Into how many regions was the earth divided by the ancient Greeks?
Answer:
The earth was divided into three regions, the winterless tropical region, the summerless polar region, and the intermediate having both 1 winter and summer.

Question 3.
What criteria was followed by KOEPPEN to classify climates?
Answer:
KOEPPEN’s classification is based upon annual and monthly r means of temperature and precipitation.

Question 4.
Why did Trewartha use only a limited number of climatic types?
Answer:
Because he realized that a large number of climatic types and sub-types are too difficult to remember.

Question 5.
How do human activities add methane and carbon dioxide to the atmosphere?
Answer:
Methane and carbon dioxide are added to the atmosphere by burning fossil fuels and by various agricultural activities.

Question 6.
What is the Greenhouse effect on the atmosphere?
Answer:
The concept of heating of the atmosphere indirectly from the earth’s surface is called the Greenhouse effect.

Question 7.
Which elements serve as major determinants of climate?
Answer:
Climate is long-term meaning daily weather conditions as determined by temperature, precipitation, pressure, winds, and humidity.

Question 8.
Which element is regarded as the basic factor of climate and why?
Answer:
Temperature is regarded as the basic factor of climate because other elements are directly or indirectly related to it.

Question 9.
Name the major divisions of the world on the basis of temperature.
Answer:
On the basis of temperature, the world has been divided into three zones, viz., Torrid, Frigid, and Temperate.

Question 10.
Mention various climatic regimes based on rainfall patterns.
Answer:
Wet climates, humid climates, sub-humid climates, semi-arid climates, and arid climates are the various regimes based on rainfall patterns.

Question 11.
Name the scholars who have attempted to devise the classification of world climates.
Answer:
Vladimir Peter KOEPPEN, C.W. Thomthwaite, and Glen T. Trewartha have so far presented a classification of world climates.

Question 12.
What climatic group is designated by ‘A’ type climate in Trewartha’s classification?
Answer:
In Trewartha’s classification, ‘A’ type climate designates ‘Tropical Humid Climate’.

Question 13.
Which type of climate is represented by ‘Ar’?
Answer:
‘Ar’ represents the tropical wet climate.

Question 14.
What is the other name of tropical wet and dry climate?
Answer:
The tropical wet and dry climate is also called the ‘Savanna’ climate.

Question 15.
Name two sub-types of polar climate.
Answer:
The two sub-types of polar climate are Tundra and Ice-cap.

Question 16.
Name the principal Greenhouse gases.
Answer:
Carbon dioxide, methane, and chlorofluorocarbon are the principal gases of the Greenhouse effect.

Question 17.
Which element is common in the principal Greenhouse gases?
Answer:
Carbon is the common element in principal Greenhouse gases.

Question 18.
In which part of the world ice-coring program have been undertaken so far?
Answer:
So far, the ice-coring programs have been undertaken in Antarctica and Greenland ice-caps.

Question 19.
Name the important elements of climate.
Answer:

1. Temperature,
2. Precipitation.

Question 20.
Who did the first classification of climate?
Answer:
Greeks.

Question 21.
What was the basis of classification done by Greeks?
Answer:
Temperature.

Question 22.
Into how many main groups did Trewartha divide the world climate?
Answer:
Into six groups.

Question 23.
Which type of climate is known for the minimum range of annual temperature?
Answer:
Equatorial climate.

Question 24.
What is the characteristic of the steppe type of climate?
Answer:
It is characterized by meager rainfall, low temperature, location in the interiors, and the effects of mountain barriers.

World Climate and Climate Change Important Extra Questions Short Answer Type

Question 1.
Explain why the tropical humid climate is found in an irregular belt of 20° to 40° latitudes.
Answer:
The tropical belt extends across the two tropics, viz., Tropic of Cancer and Tropic of Capricorn in Northern and Southern hemisphere respectively. It is one of the belts which, for part of the year, comes under the influence of trade winds but for the rest of the year is subjected to conventional rain. Moreover, the trade winds which blow from north-east and southeast also bring a considerable amount of rainfall.

Question 2.
What could be the possible consequences of the continued addition of carbon dioxide and methane gases to the atmosphere?
Answer:
The continued addition of carbon dioxide and methane gases to the atmosphere will increase the atmospheric temperature to an extent that it will cause ice to melt in the Arctic Ocean and in Antarctica. As a result, sea levels will rise causing the drowning of central lowlands and islands, altering rainfall and evaporation patterns, creating new plant diseases and part problems, and enlarging the ozone hole. Enlargement of the ozone hole, in turn, will cause more and more ultraviolet radiation to reach the earth’s surface, leading to a further rise in temperature of the lower layers of the atmosphere.

Question 3.
Match the following :

S.no. Symbol	Climatic Group
1. A	(a) Polar climate
2. C	(b) Subtropical
3. D	(c) Tropical Humid
4. E	(d) Boreal
5. F	(e) Temperate
6. B	(f) Dry

Answer:

S.no. Symbol	Climatic Group
1. A	(c) Tropical Humid
2. C	(b) Subtropical
3. D	(e) Temperate
4. E	(d) Boreal
5. F	(a) Polar climate
6. B	(f) Dry

Question 4.
Discuss the bases of climatic classifications of Koeppen and Thornthwaite.
Answer:
Koeppen’s classification is based upon annual and monthly means of temperature and precipitation. Native vegetation was considered as the best expression of the totality of climate. Similarly, Thornthwaite followed Koeppen’s principle that plant is nature’s meteorological instrument capable of integrating climatic elements like precipitation effectiveness and potential evapotranspiration.

Question 5.
Discuss the aims and objectives of Trewartha’s classification.
Answer:
Trewartha believed that people who need to understand and use the climatic environment for their own purposes should have the parts of climate presented realistically. At the same time, he also recognized the merits of the genetic type of climatic classification. According to him, “genetic not only increases interest and adds to the scientific quality of climatic analysis, but also gives an extra dimension of insight to the student’s understanding of the description.” Genetic classification of climates emphasizes the causes or origin of their formation based on weather processes.

Question 6.
What type of weather conditions characterizes sub-tropical climate?
Answer:
Sub-tropical climates are found between tropical and temperate climatic zones. In this type of climate, the temperature is above 18°C for nearly 8 months. Winters are mild and short. The coastal areas have rainfall throughout the year while continental areas receive less rainfall.

On the basis of seasonal distribution of precipitation, sub-tropical climates have two sub-types, viz., sub-tropical humid and sub-tropical dry summer climates.

Question 7.
How do the carbon dioxide contents of the atmosphere play a dominant role in causing worldwide climatic changes?
Answer:
The carbon dioxide contents of the atmosphere play a dominant role in causing worldwide climatic change. Carbon dioxide is transparent to incoming solar radiation but absorbs outgoing longwave terrestrial radiation. The absorbed terrestrial radiation is radiated back to the earth’s surface. Thus, it is clear that any appreciable change in carbon dioxide content would bring about changes in the temperature of the atmosphere.

Question 8.
Explain the Greenhouse effect.
Answer:
The concept of heating of the atmosphere indirectly from the earth’s surface is called the greenhouse effect. This effect of the atmosphere is analogous to that of a glasshouse, which lets through most of the incoming short wave solar energy but greatly retards the outgoing longwave earth radiation, thus maintaining surface temperatures considerably higher than they otherwise would be. One can build an instantaneous greenhouse. If the car is parked in the sun for about two hours with the windows closed, the interior temperature will rise. It will be more than the temperature outside.

Question 9.
Describe major reservoirs of carbon on earth.
Answer:
The carbon in the system moves between several major reservoirs. The atmosphere contains more than 750 billion tonnes of carbon at any given time, while 2000 billion tonnes are stored on land, and approximately 4000 billion tonnes are contained in the ocean. Living terrestrial organic matter is estimated to contain between 450 and 600 billion tonnes. World fossil fuel reserves also constitute an important carbon reservoir of some 5000 billion tonnes. The burning of fossil fuels adds more than 5 billion tonnes of carbon dioxide to the atmosphere every year.

Question 10.
Explain why the tropical humid climate is found in an irregular belt of 20° to 40° latitude.
Answer:
The tropical belt extends across the two tropics, viz., Tropic of Cancer and Tropic of Capricorn in Northern and Southern hemispheres respectively. It is one of the belts which, for part of the year, comes under the influence of trade winds but for the rest of the year is subjected to convectional rain. Moreover, the trade winds which blow from north-east and south-east also bring a considerable amount of rainfall.

Question 11.
What are ice-coring programs? How do they help us know about the climate of the earth in the past?
Answer:
Ice-coring programs analyze the trapped gases in Greenland and Antarctica ice-caps during the last 1,00,000 years. Analysis of these trapped gases, like oxygen, carbon dioxide, etc., reveals the cooling or heating trends of the earth, on the basis of which climatic changes have been studied in the past.

Question 12.
Distinguish between Genetic and Empirical classification of climate?
Answer:
Genetic classification of climates emphasizes the cause or origin of their formation based on weather processes. The Empirical classification, on the other hand, is based on observations related to factors for climatic differentiation.

Question 13.
Divide the world into temperature zones.
Answer:
The earth is divided into three main temperature zones :
1. Torrid Zone (Hot Zone): Occurs between 0° to 30° N and S latitudes with a mean annual temperature of more than 20°C.

2. Temperate Zones: Subdivided into
(a) warm temperate zone (between 10° to 20°C temperature, 30° to 40° N and S),
(b) cool temperate zone (0°C to 10°C temperature, 45° to 60° N and S).

3. Frigid Zones (Cool Zones): Occur between 60° to 90° N and S latitudes.

Question 14.
What is the significance of 10°C summer isotherm?
Answer:
10°C isotherm in summer indicates the limit of tree growth. In the Tundra region, trees do not grow because the temperatures are below’ 1.0°C in summer.

Question 15.
In which latitudes the tropical humid climate extend and what are its features?
Answer:
The tropical humid climate (A) stretches along the equator in the irregular belt of 20° to 40° latitude in both hemispheres. The features of this climate are that the temperature and rainfall are high throughout the year. In the coastal region, the average temperature of the coldest month is 18°C.

World Climate and Climate Change Important Extra Questions Long Answer Type

Question 1.
Give an account of any four factors which control the climate of a region.
Answer:
These are the following factors that control the climate of a region :

1. Altitude: Regions on the higher altitude have a cold climate and on the lower altitude have a warm climate.
2. Location: The climate of a region depends on the location of that region. If the location is close to the equator, the climate will be hot and wet.
3. Distance from the sea: Regions that are closer to the sea have a moderate climate and others have an extreme type of climate.
4. The direction of the mountains: The extension of the Himalayas does not allow the cold winds of Central Asia into India and the temperature of India does not come down.

Question 2.
Describe in brief Koeppen’s classification of climate.
Answer:
Koeppen’s classification is strictly empirical as it is neither based on weather process (wind belt, air masses, fronts, and storms) nor does it emphasize causes of formation of climatic type. The classification is based upon annual and monthly means of temperature and precipitation. Natural vegetation is considered the best expression of the totality of climate. On the basis of the climate needs of certain types of vegetation, Koeppen identified five major groups: A to E, to which he added a sixth category of mountain zone (H).

‘A’ is the tropical zone, with a temperature exceeding 20°C all the 12 months.

‘B’ is the sub-tropical zone, where for 4 to 11 months temperature exceeds 20°C, and for 1 to 8 months the temperature ranges between 10° to 20°C.

‘C’ is the temperate zone, where the temperature ranges between 10° to 20°C for 4 to 12 months.

‘D’ is the cold zone, with temperature ranging between 10° to 20°C for 1 to 4 months and below 10°C for 8 to 11 months.

‘E’ is the polar zone, where the temperature remains below 10°C throughout the year.

These major climatic groups were sub-divided on the basis of variation in rainfall and temperature characteristics.

Question 3.
Discuss the global climatic changes in detail.
Answer:
The atmosphere is well structured and fairly dynamic in nature. The dynamism is more complex near the earth’s surface where the changes take place both spatially and temporally. These changes may be induced internally within the earth’s atmospheric system or externally by extra-terrestrial factors. Some of these changes are the results of human intervention and, hence, may be slowed down by human efforts. Global warming is one of the changes caused by man’s continual and growing introduction of carbon dioxide as well as some other so-called greenhouse gases, like carbon and chlorofluorocarbon, into the atmosphere.

The atoms and molecules of atmospheric gases cause absorption and back radiation of sunlight by the greenhouse gases, especially water, carbon dioxide, and methane. The concentration of water in the atmosphere is controlled by evaporation from oceans. Carbon dioxide is introduced into the atmosphere by volcanism. Methane is produced by the metabolization of bacteria in wood/grass-eating animals.

Human activities also add methane and carbon dioxide to the .atmosphere by burning fossil fuels and by various agricultural activities.

The carbon dioxide contents of the atmosphere play a dominant role in causing worldwide climatic changes. The gas is transparent to incoming solar radiation but absorbs outgoing long-wave terrestrial radiation. This absorbed terrestrial radiation is radiated back to the earth’s surface. Thus, it is clear that any appreciable change in carbon dioxide content would bring about a change in temperature in the lower layers of the atmosphere. Methane, which rapidly gets oxidized into carbon dioxide, is 20 times more effective than CO₂

Rapid industrialization and technological changes, a revolution in agriculture and transport sectors have resulted in large supplies of carbon dioxide, methane and chlorofluorocarbon gases into the atmosphere.

Of the many climatic parameters, the temperature is the most affected one due to urbanization and industrialization. The thermal characteristics of urban areas are in marked contrast to those of the surrounding countryside.

Man is considered as an engine of climatic change. In support of this, rice farmers, coal miners, dairy farmers, and shifting agriculturists contribute their rate in global warming.

Question 4.
Describe the advantages of Trewartha’s classification over Koeppan’s classification.
Answer:
On the basis of grouping, climate types are either genetic or empirical. Genetic classification emphasizes the causes or origin of their formation based on weather processes. The empirical classification, on the other hand, is based on observation related to factors for climatic differentiation.

Koeppen’s classification is strictly empirical as it is neither based on weather process nor does it emphasize causes of formation of climatic type. The classification is based upon annual and monthly means of temperature and precipitation. Natural vegetation is considered the best expression of the totality of climate. Koeppen followed the principle that plant is nature’s meteorological instruments capable of integrating climatic elements like precipitation effectiveness and potential evapotranspiration.

The climate classification system devised by G.T. Trewartha represents a compromise between purely empirical and genetic methods. Besides being simple and explanatory, it combines the fundamentals of the empirical as well as genetic classification schemes. Trewartha, while proposing his climatic classification, was conscious of the fact that the classification systems of Koeppen, being based on certain statistical parameters. of a few weather elements, were cumbersome and complex. The empirical quantitative classification system, as devised by the author, produced such a large number of climatic types and sub-types that it was rather too difficult to remember them. Keeping this aspect in view, Trewartha recognized only a limited number of climatic types, i.e., 6 major types and 10 sub-types.

The major climatic groups included: Tropical humid climate
(A) Dry climate
(B) Sub-tropical
(C) Temperate climate
(D) Boreal climate
(E) Polar climate
(F) Each of these, except Boreal
(E) the climate has two sub-types.

Question 5.
Write a note on temperate climates.
Answer:
The temperate climate is found in the vast landmasses of middle latitudes (40° and 65°). This climatic band of severe winters is found between the sub-tropical and boreal type of climates.

The two sub-types of temperate climate are temperate marine and temperate continental. They are primarily demarcated on the basis of summer temperatures.

The temperate marine climate has mild winters and fairly warm i- summers. Throughout the year, the average temperature is above 0°C. Rainfall is experienced throughout the year. This type of climate is found on the western sides of continents in the temperate zone.

The temperate continental climate is found in the interior of the continents in middle latitudes. The impact of land is visible as it is characterized by harsh winters and cool summers. The extreme cooling of the ground is associated with anticyclones. Annual precipitation is low, though it takes place throughout the year. This type of climate is found in north-eastern Asia, eastern Canada, and Eurasia.

Here we are providing Class 11 Geography Important Extra Questions and Answers Chapter 1 Geography as a Discipline. Important Questions for Class 11 Geography are the best resource for students which helps in class 11 board exams.

Important Questions for Class 11 Geography Chapter 1 Geography as a Discipline

Geography as a Discipline Important Extra Questions Very Short Answer Type

Question 1.
Who first used the term ‘geography’?
Answer:
The term ‘geography’ was first used by Eratosthenes, a Greek scholar, who lived in Alexandria, Egypt during 276-192 BC.

Question 2.
What do you mean by process?
Answer:
A process is a sequence of changes systematically related through a chain of causes and effects.

Question 3.
Name the area that still remains largely inaccessible even today.
Answer:
Antarctica still remains largely inaccessible and unexplored even today.

Question 4.
What is meant by ‘culture’?
Answer:
‘Culture’ is the cumulative product of experiences. It consists of values, processes, beliefs, thoughts, ethical standards, and styles of life and living.

Question 5.
Name the oldest school of geographical thought.
An’s,
The Greek school is the oldest school of geographical thought.

Question 6.
Name two leading ‘possibilists’.
Answer:
They were Vidal dela Blache and Lucien Febvre.

Question 7.
Who were the leaders of ‘Deterministic’ philosophy?
Answer:
Fredrich Ratzel and Ellsworth Huntington were the leaders of ‘Deterministic’ philosophy.

Question 8.
Who were the discoverers of the unknown lands?
Answer:
Egyptians, Mesopotamians, Greeks, and Arabs were the first discoverers of the unknown lands.

Question 9.
The Greek scholar w housed the term ‘Geography’ for the first time.
Answer:
Eratosthenes.

Question 10.
The viewpoint about the universe stating that all planets revolve around the sun and the sun is stationary.
Answer:
Heliocentric.

Question 11.
The ancient Indian scholar who first propounded the theory of a heliocentric universe.
Answer:
Aryabhatta.

Question 12.
The technique of aerial photo interpretation.
Answer:
Photogrammetry.

Question 13.
The genetic study of landforms.
Answer:
Geomorphology.

Question 14.
The branch of biogeography that studies the man-nature relationship.
Answer:
Human ecology.

Question 15.
The doctrine believes that the environment controls human activities.
Answer:
Determinism.

Question 16.
What is cartography?
Answer:
It is the technique of drawing maps and diagrams.

Question 17.
What do you mean by geomorphology?
Answer:
It is the science that studies landforms.

Question 18.
What is cultural geography?
Answer:
It includes the cultural aspects of human groups such as ornaments, food, cloth, etc.

Question 19.
What is called economic geography?
Answer:
The discipline dealing with the distribution of economic activities of man which relate to the production of a commodity, its marketing, and distribution is called economic geography.

Question 20.
What do you understand by Hydrology?
Answer:
It is the science which deals with oceans, rivers, glaciers, etc.

Question 21.
What do you understand by Regionalism?
Answer:
The process of identifying various regions is known as v regionalism.

Geography as a Discipline Important Extra Questions Short Answer Type

Question 1.
What is geography?
Answer:
The word geography is a combination of two Greek words. ‘Geo’ meaning the earth and “Graphy’ meaning description. Thus, the meaning of geography could be to write about the earth including all that is upon it. Geography is the science dealing with the spatial distribution of various phenomena (physical & human & biotic) on the surface of the earth.

Question 2.
What is the relation of geography with other sciences?
Answer:
Geography draws its contents from both natural science and social science (sociology, economics, political science). It has also. contributed to them. Hence there are several interdisciplinary’ areas in; geography. For example. Geomorphology is closely linked with. Geology, Economic Geography with Economics, and Bio-geography with life sciences (Botany and Zoology).

Question 3.
What are the three features of systematic geography?
Answer:

1. It studies geographical facts in an individual manner.
2. It implies the detailed study of a single specific geographical factor.
3. It is explanatory and is largely interpretative.
4. A detailed study of agriculture is done by marking the agricultural regions of India.

Question 4.
Why did geography become a popular subject in school by the end of the eighteenth century?
Answer:
It was because it gave knowledge about the land to prospective migrants, administrators and traders. Gradually, along with the description of places and peoples, explanation for varying responses of people to the natural environment was also presented. Thus, geography emerged as the study of the dynamics of the man-environment relationship and its imprints on the earth’s surface.

Question 5.
What are the two ways of studying geographic problems?
Answer:
The two ways of studying geographic problems are systematic and regional. A study of a specific natural or social phenomenon that gives rise to certain spatial patterns and structures on the earth’s surface is called systematic geography. Unlike systematic geography, regional geography starts with the spatial imprints of one or all the systematic geographic processes discernible as regions of different sizes.

Question 6.
Distinguish between physical geography and biogeography.
Answer:
Geography is a spatial science dealing with the distribution of various elements and phenomena over the earth’s surface. When these elements are natural and no one is living they are called physical, e.g. land-form, climate, water, and soil. Accordingly, physical geography has branches like geomorphology, climatology, hydrology, soil geography. On the other hand, the life-form or living elements constitute the part of bio-geography. Therefore, the main branches of bio-geography are plant geography, zoo-geography, and human ecology.

Question 7.
Write in brief on the geographic methods and techniques.
Answer:
Geographers use various types of methods and techniques in order to collect and analyze information related to the surface of the earth. They include the following :

1. Field studies (physical as well as socio-economic surveys).
2. Cartography (the science of drawing maps and diagrams).
3. Quantitative geography (covers a number of mathematical and statistical techniques).
4. Spatial information system, e.g., GIS, LIS, GPS.

Question 8.
What are the natural and cultural features on the surface of the earth?
Answer:
The physical elements which are the outcome of natural processes in action are natural features, such as continents, mountains, rivers, plains, oceans, atmosphere, etc., whereas the elements which are products of human activities are cultural features, e.g., countries, villages, towns, cities, agriculture, industry, means of transport and communication, etc.

Question 9.
Name the branches of geography on the basis of the regional approach.
Answer:

1. Regional studies/Area studies comprising Macro, Meso, and Micro regional studies.
2. Regional planning comprising country/rural planning and town and urban planning.
3. Regional development.
4. Regional Analysis.

Question 10.
What is Political geography?
Answer:
Political geography looks at the space from the angle of political events and studies boundaries, space relations between neighboring political units, delimitations of constituents, and election scenario, and develops a theoretical frame to understand the political behavior of the population.

Question 11.
Name the various branches of bio-geography. What led to the development of bio-geography?
Answer:
The interface between Physical geography and Human geography has led to the development of Bio-geography. It includes:

1. Plant geography – Study of the spatial. the pattern of natural vegetation in their habitats.
2. Zoo-geography – Study of spatial patterns and geographic characteristics of animals and their habitats.
3. Ecology/Ecosystem – Study of the habitats characteristic of species.
4. Environmental geography – The environmental concern world over leading to the realization of environmental problems, such as land degradation, pollution, and concerns for conservation, led to the introduction of this new branch of geography.

Question 12.
What do you mean by Systematic geography?
Answer:
A study of a specific natural or cultural phenomenon that gives rise to certain spatial patterns on the earth’s surface is called Systematic geography. There are four branches of systematic geography :

1. Physiography
2. Biogeography
3. Human ecology
4. Geographic methods and techniques.

Geography as a Discipline Important Extra Questions Long Answer Type

Question 1.
Write a short note on Spatial Information Technology (SIT).
Answer:
The last quarter of the 20th century has put geography on a new trajectory of development with SIT as the main source of information and information processing. SIT is concerned with data collection and analysis related to physical space or the surface of the earth with the help of advanced means of information technology, such as remote sensing, aerial photographs, and satellite imageries.

They have enabled geographers to develop geographic information systems (GIS), land information systems (LIS), and global positioning systems (GPS) as location decision administration and managerial tools. Geography in the 21 st century has entered a new era of spatial information technology (SIT). They are going to be used not only in answering the question of what is where and why but also in what should be where and why. They will not only be generating information for decision-making but also will be actively participating in decision-making.

Question 2.
Describe the various branches of geography.
Answer:
Today geography is the only discipline that brings all-natural and human sciences on a common platform. It is an interdisciplinary and integrative science having numerous branches :
A. Systematic geography :

1. Physiography: Studies the physical aspects of the earth’s surface, as landforms, climate, water, and soil.
2. Plant Geography: Studies the distribution of various kinds r- of forests and grasslands. Zoo-geography studies the
   distribution of animals and micro-organisms. Human ecology studies the changing human-nature relationship and its consequences on human life and living. Environmental y geography studies the quality of the living environment and
   its implications for human welfare.
3. Human Geography: Human beings interact with nature and create a great variety of cultural phenomena like villages, Ji towns, cities, countries, factories, roads, houses, etc. The study of location and distribution of all such phenomena falls under the purview of human geography.
4. Geographic methods and techniques: Field studies, cartography, quantitation geography, and spatial information system (GIS, LIS, GPS).

B. Regional Geography :

1. Regional Studies
2. Regional Planning
3. Regional Development
4. Regional Approach

Question 3.
Discuss two perspectives of study that characterized geography in the twentieth century.
Answer:
Geography in the twentieth century became a discipline that studied the earth’s surface from two perspectives systematic and regional. The former produced sub-disciplines like physiography, climate, biography, political geography, economic geography, health geography, etc., while the latter gave rise to regional geography, regional science, regional development, regional planning, area planning, etc.

The first started with systematic knowledge to arrive at regional patterns, while the second started with a region to arrive at systematic details. In both cases, humans remained a central theme i.e., the emphasis of the study being on the impact of systematic processes and regional patterns on humans and their activities.

Question 4.
How did the Indian scholars contribute to geography in the ancient period?
Answer:
Indian scholars were among those who laid the foundation of geography in the ancient period. Atharva Veda, written around the 10th century B.C., gives the details of the then known earth, its physical features, bio-geography, and human settlements. Indians went to different parts of the world to carry the message of Indian culture, particularly of Hinduism and Buddhism. The contribution of Indian astronomers and geographers was highly advanced for their times. Aryabhatta propounded the theory of heliocentric universe a century before Copernicus, and Bhaskaracharya mentioned the gravity of the earth 1200 years before Newton. Kalidas’s description of the geography of Central India in ‘Meghaduta’ is highly professional,

Question 5.
What is the importance of Physical geography?
Answer:
Physical geography includes the study of the lithosphere, atmosphere, hydrosphere, and biosphere.

• Soils are formed through the process of pedogenesis and depend. upon the parent rocks, climate, biological activity, and time. Time provides maturity to soils and helps in the development of soil profiles. Each element is important for human beings.
• Landforms provide the base on which human activities are located.
• The plains are utilized for agriculture. Plateaus provide forests and minerals. Mountains provide pastures, forests, tourist spots and are sources of rivers providing water to lowlands.
• Climate influences our house types, clothing, and food habits.
• Climate has a profound effect on vegetation, cropping pattern, livestock farming, and some industries, etc.
• Temperature and precipitation ensure the density of forests and the quality of grassland.
• Oceans are the storehouse of resources and are rich in mineral resources, fish, and other seafood.

Soils are renewable resources, which influence a number of economic activities such as agriculture.

Physical geography is fast emerging as a discipline for evaluating and managing natural resources.