Get summary, textbook solutions, questions, answers, notes, extras, pdf for Social Science (Geography) Chapter 3: Geography of World which is a part of the SEBA (Assam Board) class 10 syllabus.
Short Introduction: The earth, the only habitat of man, is vast. Its total surface area is 510 million square km. It may be mentioned that only about 29 per cent of the earth’s surface area, that is 149 million square kin is covered by land and the remaining 71 per cent, that is 361 million square km is covered with water. The land portion of the earth is constituted by the continents like Asia, Africa, Europe, North America, South America, Oceania and Antarctica. On the other hand, the huge water portion of the earth is covered by the Pacific, Atlantic, Indian, Arctic and Southern oceans. It may be mentioned that among the continents Asia and among the oceans, the Pacific are the largest ones in the area.
As per estimates of 2015, the population of the world is 730 crores or 7.3 billion. It is notable that the topographic character, climate, soil, plants, animals, etc. are different in different places on the earth. It is due to such variations of different elements of the natural environment the population distribution and man’s ways of living are not the same in different places on the earth. Even the socio-economic advancement of different places on the earth greatly depends on the prevailing characteristics of the natural environment. That is why the areas having favourable natural environments and rich in natural resources are generally economically advanced. On the other hand, many areas on the earth having unfavourable natural environments and devoid of necessary natural resources are economically lagging behind.
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Textual Questions and answers of Geography of World
1. Write in brief about the earth’s lithosphere and hydrosphere.
Answer: The Hydrosphere is a large portion of the earth’s surface that is covered by oceans and seas, as well as rivers and lakes. The Lithosphere, on the other hand, is a part of the earth’s surface formed by land slightly above sea level.
Through the fragmentation of both units, the hydrosphere and lithosphere are penetrating each other. The lithosphere is classified into four layers. The continents of Asia, Europe, and Africa form the first part of the lithosphere; the continents of North America and South America form the second part; Australia, including a large number of islands, forms the third part of Oceania; and the continent of Antarctica forms the fourth part. The southern hemisphere contains a large proportion of the hydrosphere (57%).
The Pacific Ocean, on the other hand, is located between Asia, North America, and South America; the Atlantic Ocean is located between North America, South America, and Europe and Africa; the Indian Ocean is located in the south of Asia, east of Africa, and west of Oceania; the Northern or the Arctic Ocean is located on the north of North America, Europe, and Asia; and the Southern Ocean is located on the south of Asia, east of Africa, and west of Oceania. The northern hemisphere contains a large portion of the lithosphere (67%).
2. How was the earth in the early days according to the Continental Drift Theory?
Answer: According to the Continental Drift Theory, approximately 300 million years ago (Permian Period of the Palaeozoic Era), the earth’s lithosphere was joined as a single landmass surrounded by hydrosphere. This state of the earth’s lithosphere is known as Pangaea, and the hydrosphere that surrounds Pangaea is known as Panthalassa. After some time had passed, a narrow and elongated sea formed due to a fracture almost in the middle of Pangaea in an east-west direction. It is referred to as the Tethys Sea. The formation of the Tethys sea split Pangaea in two in a north-south direction. Its northern region is known as Angaraland or Laurasia, and its southern region is known as Gondowanaland. During the Mesozoic era, approximately 250 million years ago, the Laurasia and Gondowanaland were further divided and moved towards the equator due to splitting and continental drift. and the west, and thus the continents as we know them today, were formed. According to the theory of continental drift, North America, Greenland, and the landmasses of Europe and Asia north of the Indian subcontinent formed after the Laurasia was divided. Following the division of Gondowanaland, however, South America, Africa, Madagascar, India, the Arabian region, Malayasia and its other islands, Australia, and Antarctica were formed.
3. Write briefly about the topography of the ocean floor.
Answer: The oceans’ water surface is smooth, but the bottom topography is very rugged, with ridges, trenches, and so on. The average depth of the ocean floor is approximately 4,000 metres. The depth increases towards the centre of the ocean, where various landforms can be found. Continental Shelf, Continental Slope, Deep Sea Plain, Oceanic Canyon, Oceanic Ridge and Island, and Deep Sea Trench are common features found from the coast to the middle of oceans and seas. In fact, the Continental Shelf refers to the shallow area of the oceans and seas surrounding the coasts. Continental Slope refers to the significantly deeper part of the oceans following the continental shelf. Following the continental slope, there is a very deep oceanic floor, a deep oceanic trench, and a large number of scattered ridges, islands, and other features that appear above sea level. The Mariana Trench or Challenger Trench of the Pacific ocean floor is the deepest of the oceanic trenches.
4. Write briefly about the distribution of oceans and continents.
Answer: The continents of Asia, Europe, and Africa form the first part of the lithosphere; the continents of North America and South America form the second part; Australia, including a large number of islands, forms the third part of Oceania; and the continent of Antarctica forms the fourth part.
The Pacific Ocean, on the other hand, is located between Asia, North America, and South America; the Atlantic Ocean is located between North America and South America and Europe and Africa; the Indian Ocean is located in the south of Asia, east of Africa, and west of Oceania; the Northern or the Arctic Ocean is located on the north of North America, Europe, and Asia; and the Southern Ocean is located on the south of Asia, east of Africa, and west of Oceania.
5. Write in short about the landforms present on the earth’s land surface.
Answer: The earth, which is man’s only home, is enormous. It has a total area of 510 million square kilometres. It should be noted that land covers only about 29% of the earth’s surface area, while water covers the remaining 71%. The ocean floor is a rough surface. Ridges, canyons, oceanic hills, trenches, and other landforms can be found on the ocean floor. The oceans have an average depth of about 4,000 metres. The Mariana Trench, also known as the Challenger Trench, is the world’s deepest trench, measuring 11,022 metres below the Pacific Ocean’s surface. Hills and mountains, plateaus, plains, coastal plains, and other features of the lithosphere’s surface add to its ruggedness. The Himalayas are the world’s highest mountain range. It can be found in Asia. Everest, which stands at 8,848 metres, is the highest peak in this mountain range.
6. Briefly discuss the physical characteristics of Asia.
Answer: Asia is the world’s largest continent. The continent of Asia covers about 30% of the earth’s land area, with a land area of 44.6 million km2. It stretches from 78° north latitude to 1° north latitude in the north, and from 25° east longitude to 170° west longitude in the east. High mountain ranges, plateaus, river valleys, lowlands, coastal plains, islands, deserts, and other features abound on Asia’s continent. Mountains and plateaus abound in the country’s central region. The Himalayan mountain system includes the world’s highest peak, Everest (8,848 metres).
The Indus, Ganges, and Brahmaputra rivers flow almost entirely through the continent’s south-central region; the Yenisei, Ob, and Lena rivers in the north; the Amur, Hwang Ho, Yangtze Kiang, and Sikiang rivers in the east; and the Narmada, Tapti, Mahanadi, Godavari, Krishna, Kaveri, Barak, Menam, Irawati, and Mekong rivers in In Asia, there are numerous small and large lakes. The continent also contains the Gobi, Thar, and Arabian deserts.
7. Give your answer with reasons:
(a) Why do 90 per cent of the world’s total population concentrate in the northern hemisphere?
(b) What is the reason behind the lack of permanent human settlement in Antarctica?
Answer: (a) Because most of the landmasses in the Northern hemisphere have fertile soil, which is better for people to live in, 90% of the world’s people congregate in the Northern hemisphere. It also has sufficient vegetation, minerals, ores, and other resources required for human survival and settlement.
(b) Because of the harsh weather conditions, permanent human settlement is not possible in Antarctica. This is primarily due to the region’s extensive extreme cold climate, which sees the entire region covered in snow for the majority of the year, making life difficult.
8. Give a short answer to the following questions.
(a) Which has created a natural boundary between Asia and Europe?
Answer: Between Asia and Europe, the Ural Mountain range has created a natural border.
(b) Which is the longest mountain range in the world and where it is located?
Answer: The Andes is the world’s longest mountain range. It is situated in the western part of the continent of South America.
(c) In terms of land area which are the largest and smallest countries in the world?
Answer: Russia is the world’s largest sovereign country by surface area, while Vatican City is the world’s smallest sovereign country by surface area.
(d) Which country of the world is spread to two continents?
Answer: Russia is a country that spans two continents.
(e) In terms of population which are the largest and smallest countries in the world?
Answer: With 1.4 billion people, China is the world’s most populous country, while Vatican City is the world’s smallest country, with a population of fewer than 1,000 people.
(f) What is the name of the major mountain range of North America? In which part of the continent is it located?
Answer: The Rocky Mountain Range is North America’s most extensive and major mountain range. It runs from Alaska to Mexico in a north-south direction in western North America.
(g) Which is the world’s largest desert and where is it located?
Answer: The Sahara Desert is the world’s largest desert. It can be found in Africa.
(h) Write the names of two northerly and two easterly rivers of Asia.
Answer: The Ganges and Indus are Asia’s two easterly rivers, while Ob and Lena are Asia’s two northerly rivers.
(i) Write the names of one each of the major mountain ranges, rivers and deserts of Australia.
Answer: The Snowy Mountain, River Murray, and the Great Victoria Desert are the names of Australia’s major mountain ranges, rivers, and deserts, respectively.
(j) Write the names of three countries in Europe located in the Mediterranean region.
Answer: Spain, Italy, and Greece are the names of three European countries in the Mediterranean region.
9. Write short notes on:
(a) Pangaea: According to the Continental Drift Theory, the earth’s lithosphere was once joined as a single landmass surrounded by a hydrosphere around 300 million years ago (Permian Period of Palaeozoic Era). Pangaea is the name given to this lithosphere today. It was later divided into two parts with the formation of the Tethys sea. The northern part is known as Angaraland or Laurasia, while the southern part is known as Gondowanaland.
(b) Arctic Ocean: The Arctic Ocean is the world’s smallest ocean, covering about 14 million km2. It covers about one-fifth of the Indian Ocean’s surface. The Arctic Ocean has a circular shape because it surrounds the North Pole. In fact, the Arctic Ocean is surrounded by the northern parts of Asia, Europe, and North America. It has an average depth of 3500 metres. The Arctic Ocean is covered in thick ice for the majority of the year due to its location in the north polar region.
(c) The Continent of Oceania: The great island of Australia, as well as many other small and large islands in the southwest Pacific Ocean, such as New Zealand, Tasmania, and New Guinea, make up the Oceania continent. This continent, located in the south of Asia, is entirely in the southern hemisphere. This continent’s land area is approximately 8 million square kilometres, accounting for about 5.4 per cent of the world’s total land area. Australia is the continent’s largest country.
(d) The rivers of Asia: Many major rivers originate in Asia’s highland region of mountains, hills, and plateaus, and flow north, south, and east to the oceans and seas, forming fertile plains and deltas along the way. The Indus, Ganges, and Brahmaputra rivers flow almost entirely through the continent’s south-central region; the Yenisei, Ob, and Lena rivers in the north; the Amur, Hwang Ho, Yangtze Kiang, and Sikiang rivers in the east; and the Narmada, Tapti, Mahanadi, Godavari, Krishna, Kaveri, Barak, Menam, Irawati, and Mekong rivers in
(e) The lakes of Africa: Africa is the world’s second-largest continent. Rivers and lakes abound on the continent. The African Great Lakes are a group of lakes on the African continent that form part of the Rift Valley lakes. The series includes Lake Victoria, the world’s third-largest freshwater lake, Lake Tanganyika, the world’s second-largest lake, and Lake Malawi, the world’s eighth-largest freshwater lake by area. All of these together account for roughly one-fourth of the world’s unfrozen surface fresh water and one-tenth of the world’s fish species.
(f) The rivers of Europe: While there are hundreds of rivers that cascade and connect the countries of Europe, the Elbro in Spain, the Rhone and Seine in France, the Rhine and Elbe in Germany, the Oder and Vistula in Poland, the Danube in Austria, Hungary, and Romania, the Dnieper in Belarus and Ukraine, the Po in Italy, the Thames in the United Kingdom, the Don, Volga, and Ural in Russia, and others are worth mentioning. Onega, Ladoga, Sudskowe, Venarn, and other important European lakes include Onega, Ladoga, Sudskowe, Venarn, and others.
(g) The Appalachian Highland Region: The rugged Appalachian Highlands run from Newfoundland in the north to Florida in the south, and are characterised by hills and mountains, narrow valleys, fragmented plateaus, and other features. A series of ranges make up the mountain system. Mount Mitchell, which is located in North Carolina and reaches a height of 6,684 feet, is the system’s highest peak.
(h) The lakes of North America: Superior, Huron, Michigan, Erie, Ontario, Great Bear, Great Slave, Winnipeg, and Great Salt are among the continent’s major lakes. The Great Lakes of North America, in particular, are a series of interconnected freshwater lakes in North America’s upper mid-east, near the Canada–United States border. Around 21% of the world’s surface freshwater is contained in these lakes.
10. Write the differences between:
(a) Continental shelf and Continental slope:
| Continental shelf | Continental slope |
| The Continental Shelf is the shallow part of the oceans and seas that surrounds the coasts. | The Continental Slope follows the continental shelf and is a much deeper part of the ocean. |
| The continental shelf is about 200 metres deep. | The continental slope can reach a depth of up to 2000 metres. |
(b) Everest Peak and Godwin Austin Peak:
| Everest Peak | Godwin Austin Peak |
| It is the highest peak on the planet (8848 m). | It is the second-highest peak on the planet (8611 m). |
| It is part of the Himalayan mountain range. | It is part of the Karakoram mountain range. |
(c) The Continent of Oceania and the Continent of Antarctica:
| Continent of Oceania | Continent of Antarctica |
| In addition to Australia, Oceania is a landmass made up of numerous islands (Melanesia, Micronesia, and Polynesia). | The South Pole is located in Antarctica, which is the southernmost landmass south of the Southern Ocean. |
| Oceania’s population is estimated to be around 38 million people. | There are no permanent human settlements in Antarctica. |
(d) Gobi desert and Atacama desert
| Gobi desert | Atacama desert |
| Asia is home to the Gobi Desert. | In South America, the Atacama Desert can be found. |
| It’s dry because two air masses with little or no moisture collide, resulting in dry, stable conditions. | Because they are far from the ocean, moisture-laden clouds do not reach them, it is dry. |
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11. Choose the correct answer:
(a) Which is the world’s second-largest ocean?
Answer: (3) Atlantic Ocean
(b) Which is the smallest continent in the world?
Answer: (4) Oceania
(c) In which ocean Falkland island is located?
Answer: (1) Atlantic Ocean
(d) Which sea has separated the continents of Asia and Africa?
Answer: (2) Red Sea
(e) What has naturally separated Asia from Europe?
Answer: (1) Ural mountain range
(f) In which continent is Ecuador located?
Answer: (2) South America
(g) What is the capital of Brazil?
Answer: (3) Brasilia
Additional/extra questions and answers/solutions of Geography of World
1. How much of the earth’s surface is covered with land and water?
Answer: The total area of the earth’s surface is 510 million square kilometres. The land covers approximately 29% of the earth’s surface area (149 million square kilometres), while water covers the remaining 71% (361 million square kilometres).
2. What is the total population of the world?
Answer: In 2015, the world population was estimated to be 730 million people.
3. Name the largest ocean in the world? How many islands surround it?
Answer: The Pacific is the largest ocean in the world. There are at least 20,000 islands surrounding the Pacific.
4. Name some of the major seas under the Pacific Ocean.
Answer: Some of the major seas under the Pacific Ocean includes the Bering Sea, Okhotsk Sea, Japan Sea, South China Sea, Philippine Sea and Alaska Sea.
5. What is the average depth of the Pacific, Atlantic and Indian oceans?
Answer: The Pacific has an average depth of about 5000 metres, while the Atlantic has an average depth of about 300 metres. The Indian Ocean has an average depth of 4000 metres.
21. Give a brief description of the physiography of Asia.
Answer: The physiography of Asia can be divided into four divisions:
i. The vast plain in the north: The vast plain in the north is divided into parts:
a. The lowland in the northeast: This area is narrow and ragged in places. This region is extremely cold.
b. United Plain: The United Plain is made up of the plains of three rivers – the Lena, the Yenisei, and the Ob. This area is extremely cold. River water freezes in the winter. Rivers also cause flooding.
c.Turan-Tronei: It is a semi-deserted area. This region extends eastward from the Caspian Sea.
ii. The mountain range of middle Asia and Plateau: This region is characterised by high mountains and plateaus.Its centre is the Pamir Plateau.
iii. The Plateaus of the South: Indochina, Deccan and Arabian plateaus are the three plateaus that are in the south of Asia. While the Arabian Plateau is desert, the Deccan Plateau is fertile.
iv. Plains and Valleys: Asia has been formed by many rivers, which resulted in deltas and plains. Rivers that have formed plains include the Menam, Irawati, Brahmaputra, Ganga, Krishna, Mahanadi, Godabari, Euphretis, Taigris, Hwang Ho, and Yangtze Kiang.
v. The islands: There are several islands in northern Asia that are completely covered in snow throughout the year. This region includes Japan, Taiwan, the Philippines, Java, Sumatra, Borneo, the Andaman and Nicobar Islands, Sri Lanka, the Lakha Dweep, the Maldives, and Bahrain.
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