Class 11 Geography (India: Physical Environment) Chapter 2 Structure And Physiography

Key Concept: Geological Processes

c) Block faulting

[Solution Description] The formation of rift valleys in the Peninsular Block is mainly due to block faulting, a tectonic activity where large blocks of Earth’s crust are displaced vertically. This type of faulting leads to the creation of depressions or valleys between elevated regions.

Key Concept: Basic Identification

c) The Khadar Zone

[Solution Description] The Northern Plains in India are formed by alluvial deposits from rivers like the Indus, Ganga, and Brahmaputra. These plains consist of several zones such as Bhabar, Tarai, Khadar, and Bhangar.

Key Concept: Plate Movements

d) Equator

[Solution Description] The Indian plate has moved over millions of years due to tectonic activities. Initially, it was positioned south of the Equator before moving northward to its current position.

Key Concept: Basic Geography

b) Emergent

[Solution Description] The Eastern Coastal Plains are described as an emergent coast. This type of coast is formed when the sea level falls or the land rises, exposing continental areas that were previously underwater.

Key Concept: River System Impact, Soil Types

b) Supports dense populations due to fertile alluvial soil

[Solution Description] The river systems in the Indo-Ganga-Brahmaputra plains deposit fertile alluvial soils, which are ideal for agriculture. These nutrient-rich soils support diverse crop cultivation, attracting dense populations due to agricultural productivity. The expansive floodplains allow extensive farming operations, which sustains large communities reliant on agriculture.

Key Concept: Plateau Division

d) Indo-Gangetic Plain

[Solution Description] The Peninsular Plateau is divided into three primary sections: the Deccan Plateau, Central Highlands, and Northeastern Plateau. The Indo-Gangetic Plain, however, is not part of these divisions as it is a separate geographical entity located north of the Peninsular Plateau.

Key Concept: Elevation Range

b) 700-1,000 m

[Solution Description] The Central Highlands generally have an elevation range between 700-1,000 meters above mean sea level.

Key Concept: Submerged Coast

b) Submerged

[Solution Description] The western coastal plains of India are submerged coasts, which means they have been covered by water due to rising sea levels or land subsidence.

Key Concept: Basic Features

b) West to East

[Solution Description] The syllabus mentions that the general elevation of the Peninsular Plateau is from west to east. This affects the flow patterns of rivers in the plateau.

Key Concept: Basic Orientation

c) Southwest-Northeast

[Solution Description] The orientation of the Himalayas in the regions of Nagaland, Manipur, and Mizoram is generally from southwest to northeast. This understanding comes from studying geographical maps and orientations of mountain ranges.

Key Concept: Geological Evolution, Geoenvironmental Impact

c) Assertion is true, but Reason is false.

[Solution Description] The assertion states that the Vindhyan range has sedimentary rock formations contributing to its mineral richness, which is true as these formations have led to deposits of minerals like sandstone and limestone. However, the reason is incorrect as the Vindhyan sedimentary rocks are largely of fluvial and lacustrine origin from the Proterozoic era rather than marine origin from the Paleozoic era.

Key Concept: River Direction

a) Northwest to Southeast

[Solution Description] Before entering Bangladesh, the Brahmaputra river flows in a generally eastward direction through the Indian state of Assam, then takes a sharp turn southwards.

Key Concept: Northern Plains Formation

c) Indus, Ganga, Brahmaputra

[Solution Description] The Northern Plains of India are predominantly formed by alluvial deposits from three major river systems: the Indus, Ganga, and Brahmaputra. These rivers have deposited rich soil that supports agriculture in the region.

Key Concept: Physiographic Divisions

b) The Northern Plain

[Solution Description] According to the syllabus, the Northern Plain is one of the physiographic divisions of India.

Key Concept: Basic Division

a) Heavy rock deposits

[Solution Description] The Bhabar zone is characterized as a narrow belt where the rivers descend from the mountains and deposit heavy materials like rocks and boulders due to the steep slope.

Key Concept: River Characteristics

d) Ganga

[Solution Description] The Indo-Ganga-Brahmaputra Plain is formed by the deposition of sediments from the Ganga river and its tributaries, which result in fertile lands suitable for agriculture.

Key Concept: Climate Characteristics

d) Arid conditions

[Solution Description] The Great Indian Desert, also known as the Thar Desert, is characterized by its arid climate. This means it receives very low rainfall throughout the year, leading to dry conditions.

Key Concept: Geological Age

a) 4600 million years

[Solution Description] The age of the Earth is scientifically estimated based on geological and fossil evidence, as well as radiometric age dating techniques, most notably using isotopes like uranium-lead dating. Current estimates suggest that the Earth is approximately 4.6 billion years old.

Key Concept: Relict Mountains

a) Aravali hills

[Solution Description] The Aravali hills are part of the relict mountains in the Peninsular region, characterized by their ancient geological formation and significant erosion history.

Key Concept: River Directions

c) East to West

[Solution Description] The Brahmaputra river flows from east to west and then turns southwards near Dhubri.

Key Concept: Structure Recognition

d) V-shaped valleys

[Solution Description] The Himalayas are young tectonic mountains known for their rugged terrain, including features such as gorges and V-shaped valleys. These features result from the ongoing dynamic processes and active tectonics in the region.

Key Concept: Boundary Identification

c) Aravali Range

[Solution Description] The northern boundary of the Peninsular Block runs from Kachchh along the Aravali Range near Delhi.

Key Concept: Coastal Plains

c) Western Coastal Plain

[Solution Description] The western coastal plains of India are characterized by their unique geographical feature called ‘Kayals’ or backwaters, particularly seen in Kerala.

Key Concept: Soil Type

c) Red soil

[Solution Description] Red soil is prevalent in the eastern regions of the Peninsular plateau due to its formation from weathered ancient crystalline rocks.

Key Concept: Alluvial Plains

b) Tarai

[Solution Description] The Tarai is known for its marshy and swampy conditions. This characteristic distinguishes it from other parts of the Northern Plains such as Bhabar or Khadar.

Key Concept: Plate Movements

b) South of the equator

[Solution Description] Millions of years ago, the Indian plate was positioned south of the equator. It has moved northward over time due to tectonic movements.

Key Concept: Elevation Range

b) 700-1,000 m

[Solution Description] The Central Highlands have a general elevation that ranges between 700-1,000 m above mean sea level.

Key Concept: River Deltas

a) Godavari

[Solution Description] Rivers that form deltas at their mouths usually deposit sediments before entering larger water bodies like seas or oceans. In this case, the Mahanadi river is known to form a delta before it enters the Bay of Bengal.

Key Concept: Delta Formation

a) They form large deltas

[Solution Description] The eastern coastal plains are characterized by well-developed deltas formed by major rivers like the Mahanadi, Godavari, Krishna, and Kaveri.

Key Concept: Plate Movements

d) Northward

[Solution Description] Plate tectonics theory explains that tectonic plates move due to mantle convection currents. The Indian plate is known to be moving northward towards the Eurasian plate, causing the uplift of the Himalayas.

Key Concept: Orientation

d) Rann of Kachchh

[Solution Description] The orientation of the Indian Desert is divided such that the southern part slopes towards the Rann of Kachchh.

Key Concept: River Deltas

d) Ganga

[Solution Description] The Sunderbans delta is formed by the confluence of the Ganga and Brahmaputra rivers as they flow into the Bay of Bengal.

Key Concept: Mountain Characteristics

c) Relict and residual

[Solution Description] The Peninsular mountains of India, such as the Western and Eastern Ghats, are old and geologically stable formations. They are often described as relict and residual mountains, meaning they are remnants of older mountain ranges that have been significantly eroded over time.

Key Concept: River Identification

d) Narmada

[Solution Description] The Narmada is one of the major rivers that flow westward and empties into the Arabian Sea.

Key Concept: Directional Orientation

c) Northwest to Southeast

[Solution Description] The Himalayas in the northwestern part of India have a general orientation from northwest to southeast.

Key Concept: Basic Definition

d) Ancient gneisses and granites

[Solution Description] The syllabus states that the Peninsular Block is primarily composed of ancient gneisses and granites.

Key Concept: Plate Movement

d) North

[Solution Description] The Indian plate moved predominantly in the northward direction. This movement led to the collision with the Eurasian plate, forming the Himalayas.

Key Concept: Rainfall Source

b) Southwest monsoon

[Solution Description] The Southwest monsoon is responsible for bringing heavy rains to the Meghalaya plateau, especially impacting regions like Cherrapunji known for its high annual precipitation.

Key Concept: Mineral Resources

b) Limestone

[Solution Description] The Northeastern Plateau, particularly the Meghalaya region, is rich in several mineral resources including coal, iron ore, sillimanite, limestone, and uranium.

Key Concept: River Source

c) Indus

[Solution Description] The Northern Plains are formed by alluvial deposits from three major rivers: the Indus, Ganga, and Brahmaputra. Hence, any of these rivers can be considered a primary contributor.

Key Concept: Vegetation Type

b) Sparse shrubs

[Solution Description] Vegetation in arid regions is sparse and mainly consists of drought-resistant shrubs and grasses that can survive with minimal water.

Key Concept: Range Association

d) Deccan Plateau

[Solution Description] The hills are associated with the Deccan Plateau as they form its northern boundary.

Key Concept: Coast Division

d) Malabar Coast

[Solution Description] The Malabar Coast is the division of the western coastal plains that includes parts of Karnataka and Kerala according to the syllabus content on coastal divisions.

Key Concept: River Direction

b) Northeast to Southwest

[Solution Description] The Brahmaputra river flows from the northeast to the southwest direction before turning southwards at Dhubri.

Key Concept: Separation Channel

c) 10° Channel

[Solution Description] The body of water that separates the Andaman Islands from the Nicobar Islands is known as the Ten Degree Channel.

Key Concept: River Deltas

c) Godavari

[Solution Description] Rivers like the Ganga, Brahmaputra, and Godavari form deltas as they enter the Bay of Bengal due to sediment deposition.

Key Concept: Coastal Plain Features

c) Eastern Coastal Plain

[Solution Description] The Eastern Coastal Plain is known for its broad and emergent nature, primarily due to geological upliftment processes that have expanded its area compared to the Western Coastal Plain, which is narrow due to submergence.

Key Concept: Basic Orientation

c) Southwest-Northwest

[Solution Description] The orientation of the Himalayas in Arunachal Pradesh is southwest to northwest as mentioned in the syllabus.

Key Concept: Plate Tectonics

b) Australian Plate

[Solution Description] The Indian Plate was once part of the ancient supercontinent Gondwana, and it separated from the Australian Plate before moving northward.

Key Concept: Physiographic Features

c) Extensive area covered with alluvial deposits

[Solution Description] The Northern Plains are characterized by their vast stretches of alluvial soil deposited by rivers like the Ganga, Brahmaputra, and Indus. These plains are relatively flat and fertile, unlike the Peninsular Plateau, which has hilly and rugged terrain due to old crystalline rocks and less fertile soils.

Key Concept: Basic Geography

b) 36

[Solution Description] The syllabus states that there are approximately 36 islands in the Lakshadweep group.

Key Concept: Separation Channel

c) Ten degree channel

[Solution Description] The Andaman Islands and Nicobar Islands are two distinct groups separated by a significant water channel known as the Ten degree channel.

Key Concept: Soil Type

b) Alluvial

[Solution Description] The Indo-Ganga-Brahmaputra Plain is characterized by fertile alluvial soil, which supports diverse agriculture.

Key Concept: Geological Age

d) 4600 million years

[Solution Description] The age of the earth is mentioned in the syllabus as approximately 4600 million years.

Key Concept: Directional Orientation

b) Southwest-Northwest

[Solution Description] The directional orientation of the Himalayas in Arunachal Pradesh is from Southwest to Northwest based on their geographical extension.

Key Concept: Simple Identification

c) Narmada Valley

[Solution Description] Narmada Valley is one of the most well-known examples of a rift valley in India, formed due to tectonic movements.

Key Concept: Peak Identification

b) Anaimudi

[Solution Description] Anaimudi is recognized as the highest peak in the Western Ghats, with an elevation of 2,695 meters.

Key Concept: Tectonic Activity and Indian Plate

d) Northward

[Solution Description] The Indian plate is located in the northern hemisphere and is known to be moving northwards due to tectonic activity. This movement is part of the broader process of continental drift and has a significant impact on India’s geological structure.

Key Concept: Mountain Ranges

c) Shiwalik Range

[Solution Description] The Northern and Northeastern Mountains in India consist of ranges such as the Himalayas, which include the Greater Himalayan range and Shiwalik.

Key Concept: Geological Divisions

d) Deccan Plateau

[Solution Description] The three major geological divisions of India are the Peninsular Block, the Himalayas, and the Indo-Ganga-Brahmaputra Plain. Among the options provided, only the Deccan Plateau is part of these divisions, specifically as a subdivision of the Peninsular Block.

Key Concept: Physiographic Features

c) Plateaus

[Solution Description] The Peninsular Plateau is characterized by its extensive plateau regions, which means it has many elevated flat surfaces, known as plateaus. These are older geological formations compared to other features like plains or mountains.