CLASS 11TH Chapter 2 Structure and Physiography

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🔶 Introduction (परिचय)

• India’s physical features have evolved through geological processes over millions of years.
  भारत की स्थलाकृति लाखों वर्षों में भूगर्भीय प्रक्रियाओं द्वारा विकसित हुई है।
• Internal (endogenic) and external (exogenic) forces have shaped India’s landforms.
  आंतरिक और बाह्य बलों ने भारत की स्थलरूप रचना की है।

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🔷 Geological Structure of India

(भारत की भूगर्भीय संरचना)

तीन मुख्य भूगर्भीय भाग:

क्रम	भाग (Part)	विवरण (Description)
1.	Peninsular Block (प्रायद्वीपीय पठार)	सबसे पुराना और स्थिर भूभाग
2.	Himalayan Mountains (हिमालय पर्वत)	टेक्टोनिक प्लेट्स के टकराव से बना
3.	Indo-Ganga-Brahmaputra Plain (गंगा-ब्रह्मपुत्र मैदान)	नदी द्वारा जमा की गई जलोढ़ मिट्टी से बना

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🗺️ Physiographic Divisions (स्थलरूपीय विभाजन)

भारत को 6 मुख्य स्थलरूपीय भागों में विभाजित किया गया है:

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✅ 1. The Northern and North-Eastern Mountains

(उत्तरी एवं उत्तर-पूर्वी पर्वत)

🟡 Himalayas are divided into 4 ranges (चार श्रेणियाँ):

Range	Hindi Name	Features
Trans Himalaya	पार हिमालय	Karakoram, Zaskar ranges – Very high, dry region
Greater Himalaya	हिमाद्रि	Highest peaks (Mt. Everest, Kanchenjunga)
Lesser Himalaya	हिमाचल	Hill stations (Shimla, Mussoorie), valleys
Shiwalik	शिवालिक	Youngest, made of unconsolidated sediments

🟡 Purvanchal Hills (पूर्वांचल पर्वत):
Located in North-Eastern India – Patkai, Naga, Mizo, Manipur hills

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✅ 2. The Northern Plains

(उत्तर का मैदान)

Zone	Hindi	Description
Bhabar	भाबर	Pebble-strewn narrow belt along the foothills
Terai	तराई	Marshy area, dense forests
Bhangar	भांगर	Older alluvium, slightly elevated
Khadar	खादर	Newer alluvium, fertile for farming

🔸 Rivers: Indus, Ganga, Brahmaputra
🔸 Highly populated and agriculturally productive region
🔸 Almost level surface

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✅ 3. The Peninsular Plateau

(प्रायद्वीपीय पठार)

Sub-Part	Hindi	Details
Central Highlands	मध्य उच्चभूमि	Between Narmada & Vindhyas
Deccan Plateau	दक्कन का पठार	Triangular shape; between Western and Eastern Ghats
Eastern Ghats	पूर्वी घाट	Discontinuous hills
Western Ghats	पश्चिमी घाट	Continuous, high elevation; source of rivers

🔸 Oldest landmass
🔸 Rich in minerals
🔸 Rivers: Godavari, Krishna, Mahanadi, Kaveri

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✅ 4. The Indian Desert

(भारतीय मरुस्थल)

• Located in western Rajasthan
• Sandy soil, dunes (रेतीली मिट्टी और धोरे)
• Very low rainfall (<150 mm per year)
• River Luni is the only large river
• Thar Desert is part of this division

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✅ 5. The Coastal Plains

(तटीय मैदान)

Coast	Hindi	Features
Western Coastal Plain	पश्चिमी तटीय मैदान	Narrow, between Western Ghats & Arabian Sea – Divided into Konkan, Karnataka & Malabar coast
Eastern Coastal Plain	पूर्वी तटीय मैदान	Wide, between Eastern Ghats & Bay of Bengal – Divided into Northern Circar & Coromandel

🔸 Important rivers: Mahanadi, Godavari, Krishna, Kaveri
🔸 Deltas are found on Eastern Coast
🔸 Estuaries on Western Coast

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✅ 6. The Islands

(द्वीप समूह)

Island Group	Hindi	Details
Andaman & Nicobar	अंडमान और निकोबार	Bay of Bengal, volcanic origin, 572 islands
Lakshadweep	लक्षद्वीप	Arabian Sea, coral origin, 36 islands

🔹 10° Channel separates Andaman and Nicobar Islands
🔹 Important for biodiversity and strategic location

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📍 Extra Important Points (अतिरिक्त महत्वपूर्ण बिंदु)

• Tropic of Cancer passes through 8 Indian states.
  कर्क रेखा भारत के 8 राज्यों से होकर गुजरती है।
• 10° Channel separates Andaman and Nicobar.
  10 डिग्री चैनल अंडमान और निकोबार को अलग करता है।
• Himalayas are young fold mountains.
  हिमालय युवा वलित पर्वत हैं।

NCERT EXCERCISE

Question 1: Multiple Choice Answers

(i) Which one of the following water bodies separates the Andaman from the Nicobar Islands?
✅ Answer: 10° Channel

(ii) On which of the following hill ranges is the ‘Dodabeta’ peak situated?
✅ Answer: Nilgiri Hills

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Question 2: Short Answer Type (Write in about 60–70 words)

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(i) If a person intends to visit Lakshadweep, which coastal plain would they benefit from and why?

Answer:
If someone wants to visit Lakshadweep, they will benefit from the western coastal plain of India. This is because Lakshadweep is located in the Arabian Sea, near the western coast. Major ports like Kochi and Mangalore in Kerala and Karnataka provide easy access by sea. Also, the western coastal plain is closer to Lakshadweep than the eastern coast, so travel becomes easier and shorter.

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(ii) Where in India do we find a cold desert? Name some important ranges of this region.

Answer:
India has a cold desert in the Ladakh region of the Union Territory of Ladakh. This area is dry and very cold due to its high altitude and less rainfall. It lies in the rain shadow of the Himalayas. The important mountain ranges in this region are the Zanskar Range, Ladakh Range, and the Karakoram Range. These mountains make the climate dry and create the cold desert conditions.

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(iii) Why does the western coastal plain not have any delta?

Answer:
The western coastal plain of India does not have any deltas because the rivers that flow into the Arabian Sea, such as the Narmada, Tapi, and Mandovi, are very short and fast-flowing. They directly enter the sea without slowing down or spreading. So, there is not enough time or space for sediments to deposit and form deltas. Instead, the coastline has estuaries and narrow plains.

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Question 3: Long Answer Type (Write in about 120–150 words)

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(i) Compare the island groups of the Arabian Sea and the Bay of Bengal.

Answer:
India has two major island groups: Lakshadweep Islands in the Arabian Sea and Andaman and Nicobar Islands in the Bay of Bengal.
The Lakshadweep Islands are made of coral reefs and are flat, small, and low-lying. There are about 36 islands in this group, and the capital is Kavaratti. These islands are close to the Kerala coast.

On the other hand, the Andaman and Nicobar Islands are mostly volcanic and hilly. There are about 572 islands, and the capital is Port Blair. The two groups are separated by the 10° Channel.

The Andaman group is rich in forests and wildlife and has many tribal communities. It is also located in a more earthquake-prone area. In comparison, Lakshadweep is less populated and more peaceful but has fewer natural resources.

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(ii) Which are the major physiographic divisions found in the river valley plains?

Answer:
The major physiographic features found in the river valley plains of India, especially the Indo-Gangetic plains, are:

1. Bhabar: A narrow belt of pebbles and rocks at the foothills of the Himalayas. Rivers disappear underground here.
2. Terai: Just below Bhabar, this is a wet, marshy, and forested area where rivers reappear.
3. Bhangar: Older alluvial soil, found slightly above flood levels. It is less fertile.
4. Khadar: Newer alluvial soil, very fertile and found closer to rivers. It is often flooded and renewed.
5. Delta: At the mouth of rivers, especially the Ganga-Brahmaputra Delta, the land becomes flat and forms triangle-shaped islands.

These features make the plains highly productive and important for agriculture.

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(iii) If you are to travel from Badrinath to Sunderbans delta along the Ganga river, what major landforms will you come across?

Answer:
If you travel from Badrinath in Uttarakhand to the Sunderbans Delta in West Bengal, following the path of the Ganga river, you will pass through many landforms.

• In the beginning, you will see high mountains and glaciers in the Himalayas.
• As you move down, the river enters the Bhabar zone, a rocky region where the river goes underground.
• Then you pass through the Terai, a swampy area with thick forests and rich soil.
• After this, the river flows through the Indo-Gangetic Plains, which are flat and have Bhangar (older soil) and Khadar (newer, fertile soil).
• Finally, in West Bengal, the river spreads into many branches to form the Sunderbans Delta, the largest delta in the world, with mangrove forests and tidal rivers.

This journey shows the complete physical geography of northern India.