Structure and Physiography
NCERT Solutions • Class 11 Geography (India) • Chapter 21. Multiple Choice Questions
(i) Which one of the water bodies separates the Andaman from the Nicobar?
(c) 10° Channel
Reason: The 10° Channel is a channel approximately 150 km wide that separates the Andaman Islands to the north from the Nicobar Islands to the south.
Reason: The 10° Channel is a channel approximately 150 km wide that separates the Andaman Islands to the north from the Nicobar Islands to the south.
(ii) On which of the following hill range is the ‘Dodabeta’ peak situated?
(a) Nilgiri hills
Reason: Dodabetta (2,637 m) is the highest peak in the Nilgiri Mountains.
Reason: Dodabetta (2,637 m) is the highest peak in the Nilgiri Mountains.
2. Short Answer Questions
(i) If a person is to travel to Lakshadweep, from which coastal plain does he prefer and why?
He would prefer the Malabar Coast (Kerala).
Why: Geographically, the Lakshadweep islands are situated off the coast of Kerala. The city of Kochi on the Malabar coast is the closest mainland port and acts as the gateway (ships and flights) to the islands.
Why: Geographically, the Lakshadweep islands are situated off the coast of Kerala. The city of Kochi on the Malabar coast is the closest mainland port and acts as the gateway (ships and flights) to the islands.
(ii) Where in India will you find a cold desert? Name some important ranges of this region.
The cold desert is located in Ladakh, which lies in the Great Himalayas.
Important Ranges: The Karakoram Range, the Ladakh Range, the Zaskar Range, and the Pir Panjal Range surround this region.
Important Ranges: The Karakoram Range, the Ladakh Range, the Zaskar Range, and the Pir Panjal Range surround this region.
(iii) Why is the western coastal plain devoid of any delta?
The Western Coastal Plain lacks deltas because:
- Steep Gradient: The Western Ghats are steep, causing rivers to flow with very high velocity.
- Short Course: The rivers are short and do not carry enough silt/sediments to deposit.
- Hard Rocks: The river beds are made of hard rocks, yielding little sediment.
3. Long Answer Questions
(i) Make a comparison of the island groups of the Arabian Sea and the Bay of Bengal.
| Feature | Lakshadweep (Arabian Sea) | Andaman & Nicobar (Bay of Bengal) |
|---|---|---|
| Origin | Coral Origin: Formed by coral deposits (Atolls). | Tectonic/Volcanic Origin: Submerged mountain peaks and volcanic activity (Barren Island). |
| Size & Number | Small group of islands; total area approx 32 sq km. | Large archipelago; approx 572 islands covering a vast area. |
| Location | Closer to the mainland (Kerala coast). | Far from mainland; strategically located near Southeast Asia. |
| Topography | Flat, low-lying islands. | Mountainous terrain with dense tropical forests. |
(ii) What are the important geomorphological features found in the river valley plains?
The river valley plains (especially the Northern Plains) exhibit diverse features based on sediment deposition:
- Bhabar: A narrow belt of porous pebble-studded ground at the foothills where rivers disappear underground.
- Tarai: Marshy, swampy wetland south of Bhabar where rivers re-emerge.
- Bhangar: Older alluvium forming higher terraces/uplands, often containing calcareous deposits (Kankar).
- Khadar: Newer, fertile alluvium in the floodplains, renewed annually.
- Riverine Features: Meanders, Oxbow lakes, Braided channels, and Deltas.
(iii) Journey from Badrinath to Sunderbans: What major features will you see?
Traveling along the Ganga from source to mouth reveals three distinct stages:
1. Upper Course (Badrinath/Himalayas):
You will see deep V-shaped valleys, Gorges, rapids, and waterfalls due to intense vertical erosion by the swift river.
2. Middle Course (Haridwar to Bihar):
As the river enters the plains, the slope becomes gentle. You will see Meanders (snake-like curves), shifting river courses, and Ox-bow lakes. The river valley widens into broad floodplains.
3. Lower Course (West Bengal):
Near the mouth, the river flows very slowly. You will see it split into Distributaries and braided channels. Finally, you encounter the Sunderbans Delta (the world’s largest delta) featuring mangrove swamps and mudflats.
1. Upper Course (Badrinath/Himalayas):
You will see deep V-shaped valleys, Gorges, rapids, and waterfalls due to intense vertical erosion by the swift river.
2. Middle Course (Haridwar to Bihar):
As the river enters the plains, the slope becomes gentle. You will see Meanders (snake-like curves), shifting river courses, and Ox-bow lakes. The river valley widens into broad floodplains.
3. Lower Course (West Bengal):
Near the mouth, the river flows very slowly. You will see it split into Distributaries and braided channels. Finally, you encounter the Sunderbans Delta (the world’s largest delta) featuring mangrove swamps and mudflats.
Project Work
(i) Major Himalayan Peaks from West to East
Using an atlas, the sequence is roughly:
Nanga Parbat (J&K) $\rightarrow$ Kamet (Uttarakhand) $\rightarrow$ Nanda Devi (Uttarakhand) $\rightarrow$ Dhaulagiri (Nepal) $\rightarrow$ Annapurna (Nepal) $\rightarrow$ Mt. Everest (Nepal) $\rightarrow$ Kanchenjunga (Sikkim) $\rightarrow$ Namcha Barwa (Arunachal Pradesh).
Nanga Parbat (J&K) $\rightarrow$ Kamet (Uttarakhand) $\rightarrow$ Nanda Devi (Uttarakhand) $\rightarrow$ Dhaulagiri (Nepal) $\rightarrow$ Annapurna (Nepal) $\rightarrow$ Mt. Everest (Nepal) $\rightarrow$ Kanchenjunga (Sikkim) $\rightarrow$ Namcha Barwa (Arunachal Pradesh).