Chapter 2: Structure and Physiography

Q. 1 Describe in short, how the Himalayas were formed?

 Answer Key Points: -

1) The Himalayas have been formed due to folding by different mountain building movements. The major areas of the Himalayas have been formed by folding while minor has been formed as a result of weathering and other agents of changes.
2) It had been uplifted from the Great Geosyncline known as Tethys Sea in the folded form. These uplifted ranges had been denuded by the weathering and the other agents such as rivers and glaciers.

3) These agents of changes carved the physical features i.e. gorges, U-shaped valleys, hanging valleys, and ridges. The Indus gorge is formed as a result of erosion and weathering.
4) There are many U-shaped and hanging valleys which are the result of the erosional work of glaciers and ice.
5) Ganga, Indus, and their tributaries rise from the Himalayas. They are busy carving the minor physical features. The Himalayas peaks are snow-covered. They represent the work done by earth movements.

Q. 2 When and how Indo-Ganga- Brahmaputra plain was formed?

 Answer Key Points: -

1) Indo-Ganga-Brahmaputra Plain is a geological division of India that comprises the plains formed by the river Indus, the Ganga and the Brahmaputra.

2) Originally, it was a geo-synclinal depression which attained its maximum development during the third phase of the Himalayan mountain formation approximately about 64 million years ago. Since then, it has been gradually filled by the sediments brought by the Himalayan and Peninsular rivers.
3) Average depth of alluvial deposits in these plains ranges from 1,000-2,000 m.
4) The relief and physiography of India has been greatly influenced by the geological and geomorphological processes active in the Indian subcontinent.

Q. 3 Give the main features of Himalayas.

 Answer Key Points: -

1) Introduction: - The Himalayas geologically young and structurally fold mountains lies to the north of India. The North and Northeastern Mountains consist of the Himalayas and the Northeastern hills. The Himalayas stand almost like a strong and long wall between the Indian subcontinent and the Central and East Asian countries.

2) Location: - These mountain ranges run in the west-east direction from the river Indus to the river Brahmaputra. Himalayas in the Darjeeling and Sikkim regions lie in an east-west direction, while in Arunachal Pradesh they are from southwest to the northwest direction. In Nagaland, Manipur and Mizoram, they are in the north-south direction.

3) Length & Width: - The approximate length of the Great Himalayan range, also known as the central axial range, is 2,500 km from east to west, and their width varies between 160 and 400 km from North to South.
4) Division: - The Himalayas consist of a series of parallel mountain ranges. Some of the important ranges are the Greater Himalayan range, which includes the Great Himalayas and the Shiwalik. The general orientation of these ranges is from northwest to the southeast direction in the northwestern part of India.
5) Specialization: - The altitudinal variations are greater in the eastern half than those in the Western half.

Q. 4 Explain the characteristics or features of Northern plains? Or

Give the main features of Indo-Gangetic plains.

 Answer Key Points: -

1) Formation: - The Northern plains have been formed by the interplay of the three major river systems namely the Indus, the Ganga and the Brahmaputra along with their tributaries.
2) Size: - These plains extend approximately 3,200 km from the east to the west. The average width of these plains varies between 150 and 300 km.

3) Divisions: - From the north to the south, these can be divided into three major zones: the Bhabar, the Tarai and the alluvial plains. The alluvial plains can be further divided into the Khadar and the Bhangar.

4) Specification: - This is the most fertile physiographic unit of India formed out of alluvial soil.
5) Area: - It is a densely populated division spread over an area of 7 lakh sq. Km.

Q. 5 Give the difference between Bhabar and Tarai.

 Answer Key Points: -

 Bhabar: -

1) Bhabar is a narrow belt (8-10km wide) which runs in the west-east direction parallel to the Shiwalik foothills from the River Indus to Tista.

2) Rivers which descend (get down) from the Himalayas deposit their load along the foothills in the form of alluvial fans.
3) The Bhabar belt is comparatively narrow in the east and extensive in the western and north-western hilly region.
4) The area is characterized by dry river courses except in the rainy season.
5) The Bhabar tract is not suitable for cultivation of crops. Only big trees with large roots grow here.

 Terai: -

1) It is a 10-20 km wide marshy region runs parallel in the south of Bhabar.
2) The Tarai is wider in the eastern parts of the Great Plains, especially in the Brahmaputra valley due to heavy rainfall.

3) It is characterized by the re-emergence of the underground streams of the Bhabar belt.
4) Once covered with dense forests, most of the Tarai land (especially in Punjab, Uttar Pradesh and Uttarakhand) has been cleared and turned into agricultural land.

Q. 6 Difference between Bhangar and Khadar.

 Answer Key Points: -

	Khadar	Bhangar
1. Definition	It is lowland composed of old alluvium.	It is a highland compressed of old alluvium.
2. Deposition	It is flooded almost every year and new alluvium is deposited.	It is always about the level of the flood plains.
3. Characteristic	It is often characterised by clay soil which is very fertile.	It often contains calcareous deposits locally known as kankar.
4. Use	It is best for Intensive agriculture.	It is not much suited for cultivation.
5. Sub-name	It is called ‘bet’ in Punjab.	It is known as ‘Dhaya’ in Punjab.

Q. 7 Write the features of Peninsular Plateau? Or

“The peninsular plateaus and the Himalayas Mountains are quite different from each other in respect of stratigraphy, geological structure, and physiography.” Comment.

 Answer Key Points: -

1) Introduction: - It is a triangular landmass with an elevation of 600-900 m and composed of old crystalline, igneous and metamorphic rocks lies to the south of the river Narmada.
2) Formation: - It was formed due to the breaking and drifting of Gondwanaland and thus making it a part of the oldest landmass.

3) Specialisation: - The plateau has broad and shallow valleys and rounded hills.
4) Sub-divisions: - The plateau consists of two broad divisions namely the central highland and the Deccan plateau.
5) Appearance: - It is higher in the west and slopes gently eastwards.
6) Sub-names: - Its north-east extension is locally known as the Meghalaya and Karbi-Anglong plateau and North Cachar Hills.
7) Important Hills: - Three prominent hill ranges from the west to east are the Garo, Khasi and Jaintia hills.

Q. 8 Difference between Western Ghats and Eastern Ghats.

 Answer Key Points: -

Eastern Ghats

Western Ghats

1. Introduction/Location

Eastern Ghats are broken series of mountains lies parallel to the eastern coast of India from Odisha to Coromandel coast.
Western Ghats are the continue series of mountains lies parallel to the Western coast of India from Gulf of Combay to Kanniyakumari.

2. Height

They are Lower Mountain series having average height is about 600 above sea level.
They are higher mountain series having average height between 900 and 1600 m above sea level.

3. Extension

They stretch from the Mahanadi valley (Chhattisgarh) to the Nilgiris in the south (Tamil Nadu).
They stretch, (1,440km) from Tapti valley in the north of Mumbai to Kanyakumari in the South.

4. Important Mt. Peaks

Mahendragiri (Tamil Nadu) is the highest peak (1,501m) in the Eastern Ghats.
The Anai Mudi (2695 m) and the Doda Betta (2637) are the highest peaks in the Western Ghats.

5. Important Rivers

They have been cut across by major rivers like the Godavari, Mahanadi, Krishna and Kaveri.
No major river has cut across them.

6. Rainfall

The Eastern Ghats gets rainfall from north-east monsoon.
The Western Ghats get southward monsoon.

Q. 9 Write a short note on features and location of Thar Desert.

 Answer Key Points: -

1) Location: - The Thar Desert lies towards the Western margins of the Aravalli hills.
2) Appearance: - It is an undulating sandy plain covered with sand dunes.
3) Climate: - This region receives very low rainfall, below 150 mm per year. It has an arid climate with low vegetation cover.
4) Climatic Effect: - Streams appear during the rainy season, but soon after, disappear into the sand as they do not have enough water.

5) Important River: - Luni is the only large river, originates in the Pushkar valley of the Aravalli Range, near Ajmer and flows towards the southwest into the Rann of Kutch.
6) Division: - On the basis of the orientation, the desert can be divided into two parts: the northern part is sloping towards Sindh and the southern towards the Rann of Kachchh.
7) Special Feature: - Barchans (crescent shaped dunes) cover larger areas, but longitudinal dunes become more prominent near the Indo-Pakistan border.
8) Lakes: - The Sambhar Lake has brackish water which is the main source of obtaining salt.
9) Sub-Name: - The region north of Luni is known as the Thali or sandy plain.

Q. 10 What are the characteristics of the Andaman and Nicobar Islands? Or

Describe the two island groups of India.

 Answer Key Points: -

The Andaman & Nicobar Islands

The Lakshadweep Islands

1. Introduction/Location:

The Andaman and Nicobar islands are volcanic in origin and situated off 1353 km. away from the coast of Chennai in the Bay of Bengal. These are situated roughly between 6°N-14°N and 92°E -94°E.
Lakshadweep Islands are coral Islands situated off 396 km. away from the coast of Cochin (Kerala) in the Arabian Sea. These are scattered between 8°N-12°N and 71°E -74°E longitude.

2. Composition:

This group is made up of 572 islands, and Port Blair is the headquarters of this group.
This group is made up of 36 islands and Kavaratti of its headquarters of this group.

3. Divider:

The Andaman and Nicobar islands are separated by a water body called the 10 degree channel.
In this group 8 Degree Channel separates Lakshadweep & Maldives, 9 Degree Channel separates Minicoy & Lakshadweep and 11 Degree Channel separates Amini Island & Cannanore Island.

4. Special Feature:

India's only active volcano Barren Island lies in the Nicobar Islands.
Pamban Island also known as Rameswaram Island, (Tamil Nadu, India) is located between peninsular India and Sri Lanka.

5. Area:

The total geographical area of Andaman and Nicobar islands is 8249 Sq. km.
The total geographical area of Andaman and Nicobar islands is 32 Sq. km.

6. Renamed:

Aminidivi group of islands were renamed as The Andaman and Nicobar islands in 1973. Three islands of Ross, Neil and Havelock were renamed as Netaji Subhash Chandra Bose Island, Shaheed Island and Swaraj Island respectively in December 2018, by Prime Minister Narendra Modi, as a tribute to Subhas Chandra Bose.
The Laccadive group of islands was renamed as Lakshadweep (literally means one lakh islands) in 1973.

Q. 11 “Physical divisions of India are alternative to each other” Justify. Or

All physical divisions of India have their own importance.

 Answer Key Points: -

1) Himalayas are the storehouse of water as they give rise to Perennial Rivers which provide ample water for irrigation.

2) Himalayas serve as a climatic divide and they are the source of forest produce.
3) Northern plains have fertile soil which is suited for agriculture and also provide raw material for industries.
4) The peninsular India is the store house of minerals, which have been used by industries.
5) The Ghats are responsible for generating hydroelectricity.
6) The coastal plains are important for ports, arrival of monsoons, international trade, fishing, etc.
7) Island groups are known for scenic beauty.
8) Deserts are known for tourist attraction.

Question Bank

Q1. Explain the extension of peninsular block.
Q2. Explain the main features of peninsular block.
Q3. Discuss about the broad physiographic division of India.
Q4. Briefly explain about the "karewas" formation.
Q5. Explain the main features of Kashmir Himalaya.
Q6. Discuss about the main features of Darjeeling Himalaya.
Q7. Explain about three major zones of North Indian plain from north to south.
Q8. Differentiate between Bhangar and Khadar.
Q9. Discuss about major divisions of peninsular plateau.
Q10. Briefly explain the main characteristics of Indian desert.
Q11. Distinguish between eastern and western coastal plain.
Q12. Write a short note on Kayals.

Chapter 2: Structure and Physiography - Class 11 Geography Important Questions