Class 12 Swadesh Adhyayan Chapter 1 Assam in North East India:

Class 12 Swadesh Adhyayan Chapter 1 Assam in North East India: Its Environment, Physiography, Climate, Soil and Their Relationship Class 12 Question Answer to each chapter is provided in the list of AHSEC so that you can easily browse through different chapters and select needs one. Class 12 Swadesh Adhyayan Chapter 1 Assam in North East India: Its Environment, Physiography, Climate, Soil and Their Relationship Question Answer can be of great value to excel in the examination.

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Class 12 Swadesh Adhyayan Chapter 1 Assam in North East India: Its Environment, Physiography, Climate, Soil and Their Relationship Notes covers all the exercise questions in HS 2nd Year Swadesh Adhyayan Textbooks. The Assam Board Class 12 Swadesh Adhyayan Chapter 1 Assam in North East India: Its Environment, Physiography, Climate, Soil and Their Relationship provided here ensures a smooth and easy understanding of all the concepts. Understand the concepts behind every chapter and score well in the board exams.

Assam in North East India: Its Environment, Physiography, Climate, Soil and Their Relationship

Chapter – 1


(a) In which year the North Eastern Council was formed? 

Ans. In the year 1971 came to force on 7th Nov 1972.

(b) When the state of Sikkim was put in North Eastern Region? 

Ans. In the year 2002.

(c) In which climatic zone the Assam in included? 

Ans. In wet subtropical climatic zone. 

(d) What is the density of population per sq. km in Assam as per 2011 Census? 

Ans. 397 per sq. km.

(e) What is the percentage figure of the Brahmaputra basin area that falls in Assam to the total area of the basin in India? 

Ans. 36.33 per cent.

(f) How many types of soils are there in Assam?

Ans. There are four types of soil in Assam.


(a) How many states are there in North East India and what are the states?

Ans. There are eight states in North East India. They are – Assam, Arunachal Pradesh, Manipur, Meghalaya, Mizoram, Nagaland, Tripura and Sikkim.

(b) What are the prime aims and objectives of the North Eastern Council?

Ans. The prime aims and objectives of the NEC includes – 

1. Economic and social development of the North Eastern Region,

2. Concerted and planned endeavour for the rapid development of the region.

3. Setting in motion a new economic endeavour aimed at removing the basic handicaps that stood in the way of normal development of the region.

4. Stepping in an era of new hope in this backward area full of great potentialities. 

(c) When and between whom the Yandaboo Treaty was signed?

Ans. In the year 1826 between the British and the Burmese.

(d) Which two states of North East India remained as the UT from 1949 to 1972?

Ans. Manipur and Tripura.

(e) Which foreign countries surround the NE India?

Ans. Nepal, Bhutan, China, Myanmar and Bangladesh.

(f) Why the Brahmaputra River is called as the Trans – Himalayan River? 

Ans. As the Brahmaputra has originated beyond the great Himalayas and entered India by flowing southward across the Himalayas, so it is called as the trans- Himalayan river.


(a) Give a short description of the Brahmaputra river course after entering India. 

Ans. Out of the total basin areas of Brahmaputra – 33.6 percent falls in India of this around 41. 88 percent falls in Arunachal 36. 33 percent in. Assam, 6.0 percent m Meghalaya, 5.55 percent in Nagaland, 3.73 percent in Sikkim and 6.47 per- cent in West Bengal flowing 278 Km through mountain terrain the river enters the plain area near Pasighat. About 52 km downstream of Pasighat, it confluences with Dibong and Luhit in the conference point named Parasuram kund, from where it flows westward. The water course of the Brahmaputra splits into several divisions and again join in downstream areas. Due to such flow around 600 river islands have been formed, as a result, the width of the river in some areas have become more than 7 km. It receives numerous tributaries in its 750 km long journey Borough the Assam valley. Between Dibrugarh and Lakhimpur District the river divides into two channels and joining again about 100 km downstream, forming the Majuli Island. The Brahmaputra leaves India and enters into Bangladesh near Dhubri and flows southward.

(b) Describe the role of the Himalayas in controlling the climate of Assam. 

Ans. Among the 12 states in the Indian Himalayan Region, Assam is found to be the most vulnerable to the changing climate. The climate of Assam is highly influenced by the monsoonal wind. The presence of the hilly terrain and lofty mountains of the Himalayas with green vegetation of the surrounding keep the climate of Assam different from other states of India located between the same latitudes. For this the summer temperature found in the state is relatively lower. But because of the presence of high amount of water vapour the real feel of summer temperature found to be more than the actual. The lofty Himalayas is protecting Assam and the entire north east region from severe cold waves from the north. In the Monsoon Season due to the presence of the hills and mountains of the region, heavy orographic rain occurs. In the first week of June, Monsoon arrives and heavy rain occurs which continues till the month of September and the temperature decreases substantially · Significantly,  it has been noticed that there is some difference in climatic condition in between eastern and western Assam. Overall the Himalayas plays a very significant role in controlling the climate of Assam as well as the entire north eastern region of India. 

(c) Describe the specialties of the Majuli Island. 

Ans. The mighty Brahmaputra divides into two channel between Dibrugarh and Lakhimpur and joining again about 100 Km downstream, forms the Majuli Island. Amid the Brahmaputra this world’s biggest river island is situated. Majuli in itself had many specialities being the biggest river island and the cultural hub of Assam. It covers about 645 sq. km of area where 155 inhabited villages are there. This river island district of Assam has a population of over 150000 and a density of 300 per sq. km. Majuli is very rich in biodiversity. It is the heart of the Sattriya culture and is also world famous for the mask making culture. All of thing as a whole makes Majuli a special place in Assam.

(d) Give a brief description of the Brahmaputra as a national river route. 

Ans.Being one of the biggest rivers of the world, the mighty Brahmaputra is a very major river route of India. Realizing it immense navigation potential, the government of India in the year 1988 on 1st September declared 891 km of the river course of the Brahmaputra, from Sadia to Dhubri as the second national waterway of the country. As the river is perennial, ships can run throughout the year. Inland Water Authority of India (IWAI) is responsible for maintaining its navigational channel with the required draft. It has set up terminal facilities for trading and unloading at various strategic locations. The Brahmaputra plays a very important role in transportation and influences the economy of the region. 

(e) Give a description in how many and what are the climatic season’s Assam have been divided. 

Ans. The climatic condition of Assam is very diverse. The weather condition varies in different months of the year for which the climate of Assam has been divided into four climatic seasons namely- rainy, winter, autumn and spring.

Of the four seasons, rainy and winter seasons are comparatively longer, and the other two are of short duration. The winter season prevails from the mid November to middle of February. During this season the average temperature drops to 15°C. The morning and evening time in winter generally remains foggy. Sandy wind increasingly blows with increase of temperature from March onward and continues till April. During this period the trees become green with new leaves and for a short period prevails to spring season. After that in the first week of June, rainy season or the monsoon arrives and heavy rain occurs which continued kill the month of September and temperature decrease substantially. In between the winter and rainy season particularly from November, gradually the sky become clear and autumn reason starts which continues for a short period. Temperature falls to the lowest level between later part of December and throughout January.

(f) Describe the influence of monsoon wind in Assam. 

Ans. The climate of Assam is highly influenced by monsoon wind. In the first week of June, monsoon arrives and heavy rain occurs which continues till the month of September. The predominance of tropical maritime airman (south-west monsoon) that move over the state, mainly influence the climate of Assam. During summer monsoon season i.e. from mid-June to first September high temperature associated with heavy rainfall pre dominates the weather. Assam experience an annual average rainfall of less than 100 cm to more than 800 cm.

(g) Describe the distribution and characteristics of Laterite or Red soils in Assam.

Ans. Laterite or Red soil are usually found in wet tropical region. In Assam this type of soil is mainly found in the Dima Hasao district and Hamren area of the Karbi plateau. Moreover, in the southern margin of Golaghat district and the foothill zone of Barail range of Barak valley Laterite soil is found.

Laterite or Red soil can be characterised by many properties. This type of soil contains a very large proportion of iron and aluminium particles. Due to this, the colour of this type of soil looks red and dark in some areas. The content of Nitrogen, Potash, Phosphoric Acid and Lime in this type of soil is very little.


(a) Explain the reason for which Assam becomes rich in biodiversity.

Ans. The term biodiversity refers to the variety and variability of species on earth. The amount of biodiversity in any place in therefore, be seen as result of the complex interaction of animals, plants, grassland, climate, soil. Etc. Assam, with its unique location, amidst state of north east India, Physiographical diversity like mountain, floodplains, rivers and marshes and plateau, etc. in one of the rich biodiversity states in India. It is one of the two biodiversity hotspots that are in India -i.e. Western Ghats biodiversity Hotspot and Northeast India. Some of the important characteristics of biodiversity in Assam are-

 1. Abundance of forest.

 2. Wetland ecosystem.

 3. The network of River Brahmaputra and its tributaries.

 4. Grassland ecosystem. and 

 5. National Parks and Sanctuaries. 

Unique physiography, climatic conditions and soil types helps Assam to harbour a rich diversity of species. For the presence of the hilly terrain covered with green vegetation, heavy orographic rain occurs. The food water helps in maintaining forest coverer and crop cultivation. For the presence of many varieties of fishes, tortoise and other aquatic species in the river, their tributaries and wetlands the state of Assam become rich in biodiversity.

(b) Write a note on the distribution and characteristics of alluvial soils of Assam.

Ans. In Assam alluvial soil is found in the Brahmaputra and Barak valleys. This river built alluvial soil can be divided into two categories viz. new alluvial soil and old alluvial soil. 

The old alluvium soil is found mainly in Kokrajhar, Chirang, Baksa, Udalguri, Barpeta, Nalbari, Kamrup, Darrang, Sonitpur, Lakhimpur and some parts of Dhemaji districts. In between the new alluvial zone, near the river banks and the foothills zone generally the old alluvial soils are found. The old alluvial soil belt of southern bank of the river Brahmaputra is comparatively narrower than that of the northern bank. But it is very wide in Mankachar, South Salmara, Goalpara, Nagaon and Hojai areas. In the Barak valley, parallel to the hill ranges of Mizoram a good number of narrow but elongated older alluvium belts exist.

Major characteristics of alluvial soil in Assam are similar to that of India. 

Some of these are – 

1. It is formed by the deposition of the river load as it flows from its upper to its lower course.

2. It is light and porous, therefore easily tillable.

3. It is a fertile soil as it is rich in minerals, especially potash and lime.

4. The colour of the old alluvial ranges between dark grey to greyish yellow.

5. It is suitable for the growth of a large variety of rabi and kharif crops.

6. Soils in the drier areas are more alkaline.

(c) Having plain physiography what are the advantages of Assam compared to other states of North East India? Discuss.

Ans. Assam is the only plain state of North Eastern India. Only three 

Districts, Dima Hasao, Karbi Anglong and West Karbi Anglong are hilly.

Other districts are almost plain. 

 Physiographically, the North East India is formed by the mountains of eastern Himalayas and the Brahmaputra and Barak valleys. In which only Assam has a plain physiography, due to which Assam has and enjoys several advantages compared to other north eastern states. Some prominent characteristics of Assam having plain physiography are briefly discussed below – 

1. Climate: Northeast India has a subtropical climate that is influenced by its relief and influences from the southwest and northeast monsoons. The climate of Assam is characterised by heavy monsoon downpours reducing summer temperatures and affecting foggy nights and mornings in winters. Spring (March–April) and autumn (September–October) are usually pleasant with moderate rainfall and temperature. 

2. Temperature: Temperatures in the entire north eastern province vary by altitude with the warmest places being in the Brahmaputra and Barak River plains and the coldest at the highest altitudes. Therefore, Assam enjoys a warm temperature compared to other North East Stares. Generally, temperatures in the hilly and mountainous areas are lower than the plains which lie at a lower altitude. Summer temperatures tend to be more uniform than winter temperatures due to high cloud cover and humidity

3. Rainfall: Entire Northeast India receives less than 1,000 mm (39 in) of rainfall a year. While, Assam receive 2,000 mm (79 in) of rainfall a year whereas mountainous areas receive 2,000 to 3,000 mm (79 to 118 in) a year. In the hilly parts of North East India, it experience early monsoons with June being the wettest season.

4. Fauna: Assam is one of the richest biodiversity zone in the north eastern area and consists of tropical rainforests, deciduous forests, riverine grasslands, bamboo orchards and numerous wetland.

Having plain physiography Assam enjoys the above mentioned advantages. Apart from these geographical factor, Assam also enjoys various economic, social, cultural and political advantages compared to other north eastern states.  

(d) How the location peculiarity of Assam increased its importance in North Eastern Region?

Ans. Geographically, the entire North East falls mainly in the Eastern Himalayan Region and in the Brahmaputra and the Barak Valley. The location of Assam with its unique geographical features including the natural and economic characteristics and the political environment makes it a peculiar among the other states as well as in India too. Assam almost has a very diverse climate and biodiversity in the whole north eastern region due to its mountainous surroundings and plain terrain. Assam is the only plain province among the eight states of the North East, except the three districts of Dima Hasao, Karbi Anglong and West Karbi Anglong are hilly. The rest of the districts are almost flat. However, there are some hills around the city of Kamrup.

Due to diverse climatic features, there are several different species of plants and animals found in Assam during both summer and winter, which has made Assam a rich region of biodiversity. Assam is covered with mountains and trees due to which the climate is very different from other parts of India making it a peculiar state. In summer the temperature is relatively low in the North Eastern Region, however, the temperature of Assam is high due to the presence of water vapour in its atmosphere. Hence, the perceived temperature is higher than the actual temperature in summer. The high Himalayan Mountain in the north protects the state from the severe cold. When the monsoon winds enters the North East during the rainy season, due to the presence of the Himalayan Mountains it causes heavy rainfall. Therefore, the rivers mainly in the plain region i.e. only in Assam are flooded and cause heavy floods in several places. This naturally occurring water is used for survival in forests and for cultivation. It has been a lot of help for the farming class of the state compared to other north eastern states as well as other part of the nation. Assam is rich in biodiversity with the presence various species of fishes along with animals, birds, insects and various species of plants. They have turned it into a rich biodiverse area. 

The North East and several areas of Assam has been upgraded to tourism so far. There are many new areas that are very attractive for tourism in Assam and the entire North East. Hence, it will also create jobs for the unemployed and earn foreign exchange.

All these peculiar and diverse characteristics together increased the importance of Assam in North Eastern Region.


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