NCERT Notes for Class 9 Social Science Chapter 2 Physical features of India

India has all of the earth’s main physical features, including mountains, plains, deserts, plateaus, and islands. India’s terrain is very varied in terms of physical characteristics. Geologically, the Peninsular Plateau is one of the earth’s oldest land formations. The most recent features are the Himalayas and the Northern Plains. Alluvial deposits form the northern plains. CBSE Notes Class 9 Geography Chapter 2 on Physical Features of India can help you have a better understanding of these subjects. Additionally, you may utilise them for exam revision. These CBSE Class 9 Social Science Notes are succinct and offer an overview of the subject.

CBSE Class 9 Social Science notes will assist students in studying the topic thoroughly and clearly.

These CBSE Class 9 Social Science notes were written by subject experts who made the study material very basic, both in terms of language and format.

Major Physiographic Divisions

Table of Contents

India’s physical characteristics can be classified into the following physiographic divisions.

  1. The Himalayan Mountains
  2. The Northern Plains
  3. The Peninsular Plateau
  4. The Indian Desert
  5. The Coastal Plains
  6. The Islands

The Himalayan Mountains

The Himalayas are a geologically young range of mountains with a complex structural makeup. They extend all the way to India’s northern border.

They create an arc of about 2400 kilometres in length. Their width varies considerably between Kashmir and Arunachal Pradesh, ranging from 400 kilometres to 150 kilometres.

From the Indus to the Brahmaputra rivers, these mountain ranges run in a west-east direction. In the Eastern Himalayas, altitudinal variations are greater than in the Western Himalayas.  In its longitudinal extent, the Himalayas are formed by three parallel ranges. Between these ranges, numerous valleys exist.

Himadri Or Inner Himalayas Or Great Himalayas

    • The range to the north is referred to as the Great or Inner Himalayas, or Himadri.
    • It is the Himalayas’ most continuous range, reaching an average elevation of 6000 metres.
    • It encompasses all of the Himalaya’s most prominent peaks, including Mount Everest, Kanchenjunga, and Makalu.
    • KANCHENJUNGA IS INDIA’S HIGHEST HIMALAYAN PEAK, STANDING AT 8598 METRES.
    • Whereas Nepal is home to the world’s highest peak, Mount Everest (8848 m).
    • The Great Himalayas are perpetually covered in snow. This section’s core is composed of granite. The fold of the Great Himalayas is naturally asymmetrical.

Shiwalik Range

  • This is the Himalayas’ most remote range, with peaks ranging in elevation from 900 to 1100 metres.
  • The average width is between 10 and 50 kilometres.
  • They are made up of coarse sediments carried down by rivers from the Himalayan main ranges.
  • These valleys are strewn with large boulders and alluvium.
  • The longitudinal valleys that connect the Lesser Himalayas and the Shiwaliks are referred to as Duns and include the Dehra Dun, Kadi Dun, and Patli Dun.

Himachal Or Lesser Himalayas

This range, which runs parallel to the Himadri, is the most rugged mountain system.

It is made up of highly compressed rocks and ranges in elevation from 3700 to 4500 metres.

The average width of this Himalayan range is 50 kilometres.

It is made up of the Pir Panjal, Dhaula Dhar, and Mahabharat ranges.

The Pir Panjal range is the longest and most significant range in the world.

Additionally, they encompass valleys with well-known hill stations in areas such as Kashmir, Kangra, Kullu (all in Himachal Pradesh), Mussoorie, Nainital, and Ranikhet (all in Uttarakhand), and others.

Regional Division Of Himalayas

Additionally, the Himalayas are divided into regions from west to east. This is accomplished through the use of river valleys, specifically the Indus, Sutlej, Kali, Tista, and Dihang rivers.

Punjab, Kumaon And Assam Himalayas: 

  1. In the West, the Himalayan region between the Indus and Sutlej rivers has traditionally been referred to as Punjab Himalaya.
  2. However, it is also known regionally as Kashmir and Himachal Himalaya, respectively, from west to east.
  3. Kumaon Himalayas refers to the section of the Himalayas between the Sutlej and Kali rivers.
  4. The Nepal Himalayas are defined by the Kali and Tista rivers, while the area between the Tista and Dihang rivers is referred to as the Assam Himalayas.

Purvanchal Or Eastern Range

The Brahmaputra forms the Himalayas’ easternmost boundary. Beyond Dihang gorge, this range curves south along India’s northern-eastern border.

These hills are primarily made up of strong sandstones, which are sedimentary rocks that are densely forested. They are predominantly parallel ranges and valleys. Purvachal, or Eastern hills, refers to the Patkai, Naga, Manipur, and Mize hills.

The Northern Plains

Three river systems, the Indus, the Ganga, and the Brahmaputra, as well as their tributaries, form this plain. This plain is composed entirely of alluvial soil. It covers an area of 7 lakh square kilometres.

These plains are approximately 2400 kilometres long and between 240 and 320 kilometres wide.

Due to the fertile soil, adequate water supply, favourable climate, and terrain, they are densely populated.

Due to the gentle slope, rivers flowing from the Northern mountains slow down, resulting in the formation of riverine islands. Majuli is the world’s largest inhabited riverine island, located in the Brahmaputra.

Due to silt deposition, the rivers split into a number of channels in their lower courses. These are referred to as distributaries. They are characteristic of river deltas.

Parts Of Northern Plain

The Northern plains are divided into three sections.

  • Punjab Plain: It is the plain’s western portion. It was shaped by the Indus and its numerous tributaries. Pakistan occupies the lion’s share of this plain. The Indus and its tributaries—the Jhelum, Ravi, Sudej, Beas, and Chenab—all originate in the Himalayas. Additionally, the Punjab plain is dominated by doabs (meaning two glasses of water).
  • Plain Of Brahmaputra: It is the plain’s eastern portion. It stretches all the way from Assam to Bangladesh.

Plains Of The Ganges: It is located in the plain’s central region. It runs from Haryana’s Ghaggar river to West Bengal’s Tista river, passing through the states of Haryana, Delhi, Uttar Pradesh, Bihar, and partially Jharkhand and West Bengal.

Regions Of Northern Plain

The Northern plain is divided into four regions along its length by variations in relief features.

  • Bhabar: After they descend from the mountains, the rivers deposit pebbles in a narrow belt about 8 to 16 kilometres wide that runs parallel to the Shiwaliks’ slopes. It is referred to as the bhabar belt. The entire river system vanishes within the bhabar belt.
  • Bhangar: The majority of the Northern plain is composed of older alluvium and is referred to as bhangar. It has a landscaped appearance and is covered in calcareous deposits known as kankars.
  • Terai: South of the bhabar belt, streams and rivers re-emerge, forming the wet, swampy, and marshy terai region. It was previously densely forested and teeming with wildlife, but the majority of the forests have been cleared to make way for agriculture and to settle post-independence Pakistani migrants. There is still some forest here. This region is home to Dudhwa National m Park.

Khadar: The lowest region is the khadar or flood plain. Because the soil is renewed almost annually during floods, this area is fertile and ideal for intensive agriculture.

The Peninsular Plateau

This is an ancient crystalline, igneous, and metamorphic tableland. It was formed as a result of the disintegration and drifting of Gondwanaland; as such, it is a part of the world’s oldest landmass. The plateau is characterised by broad and shallow valleys and gently rolling hills.

This plateau is divided into two broad divisions

Central Highlands

  • This is the portion of the Malwa plateau that lies north of the Narmada river and encompasses the majority of the Malwa plateau.
  • The Vindhya range is bounded on the south by the Central Highlands and on the north by the eroded and broken  Aravallis.
  • Further westward expansion gradually merges with Rajasthan’s sandy and rocky desert.
  • As indicated by the flow of the Chambal, Sind, Betwa, and Ken rivers, it slopes from south to north.
  • The Central Highlands are more expensive in the west than they are in the east. Its eastern border comprises the Bundelkhand region. And Baghelkhand.
  • The Chota Nagpur plateau denotes the Damodar river’s further eastward extension.

Deccan Plateau

  • To the south of the Narmada river is this triangular landmass.
  • The Satpura range’s broad base forms its northern extension, while the Mahadeo hills, the Kaimur hills, and the Maikal range from its eastern extension.
  • The Deccan plateau is higher in the west and gradually descends to the east.
  • In the northeast, an extension of the plateau is visible, commonly referred to as the Meghalaya Karbi-Anglong plateau and North Cachar hills.
  • A fault separates it from the Chotanagpur plateau. From west to east, the Garo, Khasi, and Jaintia hill ranges are prominent.

Western And Eastern Ghats

  1. These ghats define the Deccan plateau’s eastern and western boundaries.
  2. The Western Ghats (alternatively referred to as the Sahyadri range) run parallel to the Western coastline. The Western Ghats are more elevated than the Eastern Ghats.
  3. Their average elevation is between 900 and 1600 metres, compared to 600 metres in the Eastern Ghats.
  4. The ghats generate orographic rain by forcing rain-bearing moist monsoon winds to rise along the ghats’ western slopes.
  5. The Western Ghats rise in elevation from north to south.
  6. The highest peaks in this region are Anai Mudi (2695 m) and Dada Betta (2637 m).
  7. These hills are home to the well-known hill stations of Udagarnandalam (commonly referred to as Oorv) and Kodaikanal.
  8. The Western Ghats are a continuous range of mountains that can only be crossed via passes. From the Mahanadi valley in the north to the Nilgiris in the south, the Eastern Ghats run.
  9. The Eastern Ghats are discontinuous and irregular, with rivers draining the Bay of Bengal cutting through them.
  10. Mahendragiri (1501 m) is the Eastern Ghats’ highest peak.
  11. Shevroy and Javadi hills are located in the Eastern Ghats’ south-east region.
  12. In Tamil Nadu, the Nilgiri hills are located at the confluence of the Eastern and Western Ghats.

Deccan Trap

The western portion of the plateau, dubbed the Deccan Trap, is covered in black volcanic soil. The rocks are igneous and have been eroded to create black soil, which is renowned for cotton cultivation.

The Indian Desert

  1. This is located on the western rim of the Aravalli mountains.
  2. It is made up of a wave-like sandy plain with a variety of sand dunes.
  3. It receives less than 150 millimetres of rainfall per year.
  4. It has a semi-arid climate and sparse vegetation.
  5. Only during the monsoon season do streams appear here.
  6. Luni Is The Region’s Only Major River.
  7. The majority of this desert is covered by crescent-shaped sand dunes called Barchans, but longitudinal dunes can also be seen on the western edge of this region near the India-Pakistan border.
  8. The Thar desert is the name given to this desert.

The Coastal Plains

The Peninsular plateau is bounded on the west by the Arabian Sea and on the east by the Bay of Bengal. Between the Western Ghats and the Arabian Sea, the western coast is a narrow plain. It is divided into three sections.

  • The northern portion of the coast is referred to as the Konkan (Mumbai-Goa)
  • The southern section is referred to as the Malabar coast.
  • The central section is referred to as the Kannad plain.

The plains, which run parallel to the Bay of Bengal, are wider and more level. It is referred to as the Northern Circar in the north and the Coromandel coast in the south.

On this coast, rivers such as the Mahanadi, Godavari, Krishna, and Kaveri have formed extensive deltas. Lake Chilika is the Eastern seaboard’s largest saltwater lake (Odisha). It is well-known for being a wintering ground for migratory birds. It is located southwest of the Mahanadi Delta.

The Islands

India has two island groups. These are

The Islands Of Andaman And Nicobar

The Islands Of Andaman And Nicobar are two island chains that are densely forested. The Andamans are larger.

They are more numerous and widely distributed. The group of islands is broadly classified into two groups: the Andamans to the north and the Nicobars to the south. These islands are thought to be elevated segments of submarine mountains. The islands’ southernmost point (dubbed Indira Point) is further south than the Indian mainland.

The Lakshadweep Group Of Islands is located near the Malabar coast (Kerala). This island group is made up of small coral islands. They were previously referred to as Laccadive, Minicoy, and Amindive. These were renamed Lakshadweep in 1973. They occupy a small area of 32 square kilometres.

Lakshadweep’s administrative headquarters are located on the island of Kavaratti. Pitti Island, which is uninhabited, is part of this group.

Barren Island in the Andaman and Nicobar Islands is home to India’s only active volcano. This group of islands is home to an abundance of flora and fauna. They are located near the equator and have an equatorial climate with dense forest cover.

NCERT questions & answers from Chemical Reactions and Equations

Question 1.

Choose the right answer from the four alternatives given below:

(i) A landmass bounded by sea on three sides is referred to as

(a) Coast

(b) Island

(c) Peninsula

(d) None of the above

Ans. (c) Peninsula

A peninsula is a landform that is mostly surrounded by water, but not entirely. A peninsula is connected to a larger landmass, such as a continent or an island, but it prominently extends out into the water from the mainland.

The term is derived from the Latin phrase paene insula, which means “almost an island.”

(ii) Mountain ranges in the eastern part of India forming its boundary with Myanmar are collectively called

(a) Himachal

(b) Uttarakhand

(c) Purvanchal

(d) None of the above

Ans. (c) Purvanchal

Purvanchal is a sub-region of Uttar Pradesh located within the Awadhi and Bhojpuri region. It is located in the eastern part of Uttar Pradesh.

The region corresponds to the ancient kingdoms of Kashi and Malla, which is where Buddha died. Purvanchal achieved independence from Avadh and Mughal rule under Zamindar Balwant Singh, a Bhumihar zamindar from Benaras State who later founded the Banaras state’s Narayan dynasty.

In recent years, there has been a push for secession from the state of Uttar Pradesh. Despite its political activism, Purvanchal ranks low on the HDI index and remains India’s most underdeveloped region, with a scarcity of industries and employment opportunities driving people to the metropolises of Delhi and Mumbai.

(iii) The western coastal strip, south of Goa is referred to as

(a) Coromandel

(b) Konkan

(c) Kannad

(d) Northern Circar

Ans. (c) Kannad

(iv) The highest peak in the Eastern Ghats is

(a) Anai Mudi

(b) Kanchenjunga

(c) Mahendragiri

(d) Khasi

Ans. (c) Mahendragiri

Mahendragiri is a mountain located in the Rayagada subdivision of Odisha’s Gajapati district. It is located at an elevation of 1,501 metres in the Eastern Ghats (4,925 ft)

Question 2.

(i) What are tectonic plates?

Ans.Tectonic plates are large portions of the earth’s crust that have been broken by increasing convection currents

(ii) Which continents of today were part of the Gondwana land?

Ans. South America, South Africa, Australia, and Antarctica are the continents.

(iii) What is bhabar?

Ans. Ans: Bhabar is a short swath of the Ganga plain covered with pebbles that runs parallel to the Shiwalik slopes.

(iv) Name the three major divisions of the Himalayas from north to south.

Ans. 

(a) The Greater Himalayas or Himadri (Inner Himalayas)

(b) Himachal or Lesser Himalayas (Middle Himalayas)

(c) The Shiwaliks (Outer Himalayas).

(v) Which plateau lies between the Aravali and the Vindhya ranges?

Ans. Between the Aravali and the Vindhya ranges is the Malwa plateau.

(vi) Name the island group of India having coral origin.

Ans. The Lakshadweep Islands are a coral-based island group.

Question 3.

Distinguish between:

(i) Converging and diverging tectonic plates

Ans:

Converging Plates:

  • Converging plates are colliding tectonic plates.
  • They either collide and shatter as they approach one another, or they collide and submerge one another.
  • Converging plates result in folding.

Diverging Plates:

  • Divergent plates are tectonic plates that are eroding away from one another.
  • They travel apart without colliding or shattering.
  • Diverging plates result in the formation of fissures or fractures in the earth’s crust.

(ii) Bhangar and Khadar

Ans:

BHANGAR:

  • This is a prehistoric alluvial plateau.
  • It is maintained at a constant elevation above the floodplain. It is frequently covered in calcareous nodules referred to as kankar.
  • This is not the optimal plant for cultivation.

Khadar:

  • This is a newly formed alluvial lowland.
  • Almost every year, it is flooded, resulting in the deposition of additional alluvium.
  • A common feature is clay soil, which is quite fertile.
  • It is ideal for intensive agriculture.

(iii) Western Ghats and Eastern Ghats

Ans: 

Western Ghats:

  • The Western Ghats form the Deccan Plateau’s western boundary.
  • They are continuous and are accessible only via passes such as Pal Ghat, Bhor Ghat, and others.
  • They run parallel to the western coast of the Arabian Sea.
  • In the south, they are taller, and their height increases as they move south.
  • The average elevation is between 900 and 1600 metres.
  • Anai Mudi is the highest peak at 2,695 metres above sea level.

Eastern Ghats :

  • The Eastern Ghats form the Deccan Plateau’s eastern boundary.
  • They are irregular and discontinuous due to the rivers that flow into the Bay of Bengal.
  • They are located on the eastern coast of the Bay of Bengal.
  • They are taller in the north, and the mountains grow in height as one travels north.
  • The average height of a person is 600 metres.
  • Mahendragiri is the highest peak at 1,501 metres above sea level.

Question 4.

Describe how the Himalayas were formed.

Answer:

  • India’s earliest landmass (the peninsular section) was formerly a part of Gondwana, a supercontinent comprising India, Australia, South Africa, and South America.
  • Convection currents shattered the earth’s crust following the separation of the Indo-Australian plate from Gondwana land, causing the Indo-Australian plate to drift north.
  • As a result of the northward drift, this plate collided with the much larger Eurasian plate.
  • The collision folded the sedimentary strata that had accumulated along the Tethys geosyncline, resulting in the formation of the western Asian and Himalayan mountain ranges.
  • With their lofty peaks, deep valleys, and swift-flowing rivers, the Himalayas exemplify a youthful landscape.

Question 5.

Which are the major physiographic divisions of India? Contrast the relief of the Himalayan region with that of the Peninsular plateau.

Answer:

The major physiographic divisions of India are:

  • The Himalayan Mountains
  • The Northern Plains of India
  • The Peninsular Plateau
  • The Indian Desert
  • The Coastal Plains
  • The Islands

Relief of Himalayan Region

  • The Himalayas are the world’s youngest and highest mountain range, formed by numerous parallel groups.
  • They are the result of the Tethys Sea’s bed being bent by sedimentary rock strata.
  • This region is home to some of the world’s highest peaks. Numerous these peaks, including Mt. Everest and Mt. K2, are above 6000 metres and remain snow-covered throughout the year.
  • The Himalayas, with their jagged peaks, gorges, deep valleys, and waterfalls, exemplify a youthful topography.

Relief of Peninsular Plateau

  • It is a crystalline igneous and metamorphic rock formation made up of thousands of years old crystalline igneous and metamorphic rocks.
  • Gondwanaland was shattered, resulting in the formation of the Peninsular Plateau.
  • Decades of erosion have rounded the hills of the Peninsular Plateau, including the Aravallis and the Nilgiris.
  • The Peninsular Plateau is defined by rounded hills, expansive valleys, and narrow gorges.

Question 6.

Give an account of the Northern Plains of India.

Answer:

  • The Northern Plains of India are alluvial plains in the country. 
  • They are formed by sediments transported from the mountains and deposited in the depression created by the Himalayan uplift by rivers, particularly the Indus, Ganga, and Brahmaputra, as well as their tributaries.
  • The plains extend over a 7 lakh square kilometre area. This plain stretches 2,400 kilometres in length and 240 kilometres in width.
  • The region is densely populated and intensively farmed.
  • It is a highly productive agricultural region of India, with abundant water and a temperate climate.
  • India’s Northern Plains are separated into three sections.
  • The Punjab Plains comprise the western portion of the Northern Plains. They have been shaped by the Indus River and its tributaries.
  • Between Ghaggar and the Teesta River, the Ganga Plains stretch across the states of Haryana, Delhi, Uttar Pradesh, Bihar, Jharkhand, and West Bengal.
  • The Brahmaputra Plain is located east of the Ganga Plains. It is bounded by the state of Assam..

Question 7.

Write short notes on the following:

(a) The Indian Desert

Ans. 

  • The Indian desert lies west of the Aravali highlands. It is a sandy plain covered in sand dunes.
  • Barchans cover a sizable portion of the desert (crescent-shaped sand dunes). Near the Indo-Pakistan border, longitudinal sand dunes are more prevalent.
  • It is characterised by a dry climate with sparse vegetation and an annual rainfall of less than 150 millimetres.
  • Rivers/streams appear and then vanish into the sand during the wet season.
  • Due to a lack of water, they are unable to reach the sea. The Luni River is the only significant river in this region

(b) The Central Highlands

Ans. 

  •  The Central Highlands are located on the Peninsular plateau north of the Narmada River. These highlands are composed of strong igneous and metamorphic rocks.
  • It is bounded on the north by the Aravali range. The Central Highlands consist of the Malwa plateau to the west and the Chotanagpur plateau to the east.
  • The Central Highlands are broad in the west and narrow in the east. The Malwa plateau’s eastern expansion is referred to as Bundelkhand and Baghelkhand. 
  • In the east, the Damodar river, a southern tributary of the Ganga, drains the Chota Nagpur plateau.

(c) The Island Groups of India

Ans. There are two groupings of islands in India:

(a) Lakshadweep Islands

(b) Andaman and Nicobar islands group

Lakshadweep Islands:

  • These island clusters are located west of Kerala’s Malabar coast in the Arabian Sea.
  • These are coral islands formed as a result of dead coral deposition.
  • The islands total 32 square kilometres in area. Lakshadweep’s administrative capital is located on the Kavaratti Islands.
  • They have a diverse range of flora and fauna. On the desolate Pitti island, there is a bird sanctuary

Andaman and Nicobar Island:

  • These islands in the Bay of Bengal are the raised portion of submerged mountain ranges that jut out into the sea.
  • They are more numerous and larger. Some were formed by volcanic activity, such as Barren Island, the world’s only active volcano.
  • These islands are strategically significant due to their proximity to Southeast Asia.
  • The capital of the country is Port Blair.
  • It has an equatorial climate and is densely forested
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