Students can Download 1st PUC Geography Previous Year Question Paper March 2014 (South), Karnataka 1st PUC Geography Model Question Papers with Answers helps you to revise the complete Karnataka State Board Syllabus and score more marks in your examinations.
Karnataka 1st PUC Geography Previous Year Question Paper March 2014 (South)
Time: 3 Hrs 15 Min
Max. Marks: 100
- Answer All the questions.
- Draw map and diagrams wherever necessary.
- Question No. V is on cartography
- Blind students attempt only VA, 52, 53 and 54 instead of V – B, C and D.
I. Answer the following questions in a word, or a sentence each: (10 × 1 = 10)
What is Bio geography?
A discipline that deals with the living organisms on the earth.
What is earth’s axis?
An imaginary line joining north and south poles passing through Centre of the earth.
What is weathering?
Process of disintegration and decomposition of rocks.
How does granular disintegration occur?
Breaking of rocks into different mineral grains.
Which region is predominant in carbonation?
In which layer of the Atmosphere Aurora found?
What is Hydrological cycle?
The cyclic movement of water between the atmosphere and surface of the earth.
What is salinity?
The total amount of dissolved solids in the ocean water.
What are Biomes?
A district group of life forms and the environment in which they are found.
Mention the International boundary line between India and China?
The Me Mahon line
II. Answer any ten of the following in two or three sentences each: (10 × 2 = 20)
Mention any two causes for the occurrence of volcanoes.
The temperature inside the Earth increases with the increasing depth (1°c per 32m)
Formation of magma because of increase in temperature in pressure.
What is delta? Name any two types of delta.
A triangular shaped alluvial deposition formed at the mouth of the river is called ‘Delta’. Important types of deltas are
a. Arcuate or common delta
b. Bird – foot delta
What is the role of Ionosphere in the Atmosphere?
These electrically charged particles are known as “Ions” and hence this layer is known as Ionosphere. Radio waves transmitted from the Earth are reflected back to the Earth by this layer. It helps in Radar, Navigator communication. The ionosphere protects us from meteors.
Mention the important features of Inversion of temperature.
It is a process of temperature increases with increasing height in troposphere. This feature is common during winter season, less cloudiness, slow movement of winds, and clear sky in the mountain valley.
Mention the features of cyclonic winds.
Cyclone is a small low pressure area in the center surrounded by high pressure. The winds blow spirally towards the low pressure a area and form convergence of winds. In the northern hemisphere the direction of cyclonic winds is anti clock-wise and in the Southern hemisphere it is clockwise.
Name the four submarine relief features of the ocean floor.
The major submarine relief features are
- The Continental slope
- The Continental Slope
- The Deep Sea Plains
- The Ocean Deep.
Mention any two uses of tides.
Tides are useful to man and a society in various ways. They are:
- Tides increase the depth of water in shallow harbours and help navigation during high ties.
- Tides clean the entrance of ports, harbours and river mouths.
- Tides help fishing and other aquaculture activities.
- Tides promote salt and foam production in the coastal areas.
- Tides promote the generation of tidal energy
Write the latitudinal and longitudinal extent of India.
The latitudinal extension is 8°4’ N to 37°6’ N and the longitudinal extent is 68° 7’ E to 97°23 E .The latitudinal and longitudinal extent of India is around 30° The country stretches to 3214km from North to South and 2933 km from West to East.
Distinguish between Bhangar and Khadar plains.
Bhangar Plains: It is an Old Alluvium. It contains the Kankar nodules with calcium carbonates and it is less fertile.
Khadar Plains: It is a new alluvium. It does not contain the kankar nodules and it is very fertile.
Name any two Ghats of Western Ghats.
Thalghat, Bhjorghat, Palghat, Agumbe ghat, Shiradighat, Charmadighat are the major Ghats of the Western Ghats.
Name the two most important seismic zones of India.
Zone V: This is the most severe seismic zone and is referred as very high damage Risk zone. The areas are Northeastern states, parts of Jammu Kashmir, Uttarkhand, and Bihar and Kutch region.
Zone IV: This zone is second in severity zone. Northern regions of Jammu and Kashmir, Himachal Pradesh, parts of Bihar, UP, Gujarat, West Bengal.
Name any two factors that cause drought and famine.
The main causes for the occurrence of drought and famine are reduction in annual rainfall, long period scarcity of surface and underground water, scarcity of stored water, excess utilization of freshwater. Overgrazing, deforestation. Improper agricultural practice, mining.
III. Answer any eight of the following questions in 25 to 30 sentences each. (8 × 5 = 40)
Explain the important branches of Geography.
1. Physical Geography.
The field of physical geography is wide as it includes the study of the entire surface of the earth and also its physical and biological process as well as their morphology. Modern geography has witnessed the development of many branches and some of them even grown into separate disciplines.
Some of the important branches of physical geography are as follows:
- Geomorphology: It is a systematic study of landforms, such as mountains, plateaus, plains, valleys, etc.
- Climatology: Climatology encompasses the study of structure of atmosphere and elements of climates and climatic types and regions.
- Meteorology: The scientific study of atmosphere condition is called meteorology.
- Pedology: It is the scientific study of soil formation, structure, texture, chemical composition and their influence on plant growth.
- Hydrology: Hydrology studies the realm of water over the surface of the earth including oceans, lakes, rivers and other water bodies and its effect on different life.
- Seismology: It is the study of Earthquakes, their effects and distribution.
- Astronomical Geography: It is the study of heavenly bodies of the space like planets, satellites, stars etc in relation to the earth.
- Volcanology: It is the scientific study of tectonic process of volcanoes.
- Astronomical geography: It is the study of heavenly bodies of the space like planets, satellites, stars etc in relation to the earth.
- Bio-geography: It is the systematic study of the distribution of plants and animals.
- Hydrology: The study of water on the earth’s land is known as hydrology.
- Oceanography: The study of waves, tides and currents and the other characteristics of oceans, known as oceanography.
2. Human geography: It deals with man and his activities particularly cultural environment factors on man made factors, Important among them are culture, Society, agriculture, mining, industry, transport forming trade population etc.
Some of the important grander of Human geography are as fallows:
1. Political geography: It deals with spatial unit, people distribution, political behavior, political divisions etc.
2. Economic geography: It refers to basic attributes of the economy such as production, distribution exchange of goods and consumption. It deals with the spatial aspects of production, distribution and consumption and also helps on understanding the most proper location for establishing different human activities.
3. Commercial Geography: It deals with the spatial distribution of trade and commercial practices etc.
4. Population Geography: It helps to understand the distribution, growth density, migration and various other components of population.
How do seasons occur? Explain with neat diagram.
Seasons occurs as an effect of earth’s revolution. Seasons refers to periods of a year which have some peculiar climatic conditions. Seasons are caused due to the following.
- The inclination of the earth’s axis.
- The parallelism of the earth’s axis
- Revolution of the earth.
There are four seasons in a year. They are:
1.Summer 2. Autumn 3. Winter 4. Spring. As per the international Calendar, the four seasons have a period of 3 months. From the point of view of the earth’s indication, there are four positions of solstices and equinoxes. So, there are four seasons according to the positions of the earth in one complete revolution around the sun. Those four seasons are:
a. Summer Season: On June 21st the northern hemisphere is tilted towards the sun while the southern hemisphere is tilted away from the sun. The rays of the sun fall vertically on the Tropic Cancer and the areas within the Artistic circle remain in sunlight for all 24 hours. The northern hemisphere has longer days and shorter night. At this time the northern hemisphere has longer days and shorter night. At this time the northern hemisphere enjoys summer season and this portion is called “summer solstice”. Solstice means sun stops.
b. Autumnal Season: On 23rd September the northern hemisphere and the southern hemisphere are equally inclined or tilted towards the sun. The sun rays are vertical at the equator. As a result, the days and night are equal all over the world. At this time, in the northern hemisphere the season is neither hot nor cold. It is a situation between summer and winter seasons. It is called autumn season. At this time in the southern hemisphere, there is spring season. This position of the earth on 23rd September is known as autumnal equinox.
c. Winter Season: On 22nd December the southern hemisphere is inclined or tilted towards the sun, and northern hemisphere is inclined or tilted away from the sun. The sun is vertical at the Tropic of Capricorn, i.e. at 23 lA°S. At this time there is winter season in the northern hemisphere, and summer season in the southern hemisphere. This position is known as winter solstice.
d. Spring Season: On 21st March the northern and southern hemisphere are equally inclined towards the sun. The conditions are similar to those of autumnal equinox. From 21st March to 21st June, the earth is moving on its northern limits. During this period, there is spring season in the northern hemisphere and autumn season in the southern hemisphere. This season lasts for three months and continues with fresh cycle of summer. In India, the beginning of the spring is considered very auspicious and is celebrated as the first day of the year.
What is physical weathering? Explain the factors affecting physical weathering.
The disintegration of rocks without any chemical change in their compost in is known as mechanical or physical weathering. The disintegration of rocks occurs mainly due to the influence of temperature variation, frost action, wind action, rainwater, etc.
A. Surface are heated and expand. During the nights the rock surfaces are cooled due to , fall in temperature, rocks contact. The repetition of exemptions and contraction causes tension and stress which leads to cracks in the rocks. Then the rocks disintegrate into i blocks. This process is known as Block disintegration, Rocks are made of different types of minerals.
So the different parts of the same rock mass react differently to temperature. This leads to differential expansion and contraction inside the rocks. The rocks break up into smaller grains. This process of weathering is, called “Granular disintegration”. Due to variat Temperature in the upper and lower layers, the outer layers of rocks peel out into the uric shells. This process of weathering is known as “Exfoliation”.
B. Frost: Rocks are disintegrated due to freezing and thawing of water in the cracks or joints in the rocks. This frost action is more important in the temperate and cold regions. The water present in the cracks of rocks freezes during the night due to fall in temperature below freezing point. When water freezes it expands by 1/10 its volume. It thaws (melts) during the day, due to increase of temperature and it contracts in volume. This alternative freezing and melting of water widens other cracks in the rocks, splits and breaks then into blocks. This is known as frost shattering.
C. Rain: Sometimes, when rain falls suddenly on highly heated rocks in hot desert numerous cracks are developed. This is just like a heated chimney of a lamp, when a drop of water falls on it. The repetition of this mechanism causes disintegration of rocks. In humid region, when torrential rain occurs, the drops strike the rock surface and loosen the particles.
D. Wind: In the deserts the wind blows with greater speed carrying with it sand and rock materials, they collide with each other or strike against the loose rock and cause weathering. In deserts the wind cause this type of weathering on a large scale.
E. Sea waves: Sea waves strike the costal rocks. Repeated striking enlarges the incipient joints. Fractures and cause breaking of rocks into small blocks. Weathering also takes place due to hydraulic pressure, abrasion and attrition caused.
F. Slope: A steep slope helps in weathering. In mountainous and hilly area, sometimes, on account of gravity, blocks of rocks move down the slope while rolling down the slope, they strike against other block and break up into pieces.
G Gravitation: the gravity of Earth makes the huge rocks to roll towards the slope. Rolling rocks strike against each other and break up into pieces.
What is landform? Explain the different types of geomorphic processes.
A land form is any natural formation of rock and dirt, found on the earth. A landform can be as. large as a mountain range or as small as a hill. Landforms are natural features of the landscape, natural physical features of the earth’s surface eg. Valleys, plateaus, Mountains, plains, hills loess plains. The minor landforms include hills, ridges, valleys, basin etc. According to Geo-scientist the landforms are formed by the forces acting from the interior and on the surface of the Earth.
The processes carried out by Endogenic and Exogenic forces are called geomorphic processes. Endogenic forces: The internal forces are also known as endogenic forces. These are mainly the land building forces. Diastrophism includes all these processes; that move, elevate or build portions of the earth’s crust.
The internal forces are also known as endogenic forces. Exogenic Forces: The external forces are also known as Exogenic forces. These forces are found on the surface of the Earth, Which bring changes through degradation and aggradations process. River, glacier, wind, sea waves are the major sources of external forces.
Explain the factors influenced on the distribution of temperature.
The distribution of temperature on the surface of the earth is not uniform. It varies from. region to region due to various factors. The various factors affecting the distribution of atmospheric temperature are:
a. Latitude or distance from the equator: Places close to the equator have higher temperature and are warmer than places awaylfom the equator This is because the Sun rays reach the Earth after passing rays reach the Earth after passing through the layers of the atmosphere. In the low latitudes the Sun rays are direct and have to travel a lesser extent through the atmosphere. Hence, the heat of these rays is more intense. But in high latitudes the Sun rays are slanting and have to passes through a greater extent of atmosphere.
b. Altitude: Temperature decreases with altitude. This is because the heat absorbing elements are found in lower altitude. So the places near the Earth’s surface are warmer than places higher up. This is because air near the surface is denser and contains gases like carbon dioxide, water vapour and other gases. Temperature decreases with increase in height at an average rate of l°C/165m or 6.4°C/1000m.
c. Distance from the sea: this factor also influence on the distribution of temperature and differential heating of land and water. Land gets heated faster compared to water. Water takes longer time to get heated and to cool than land. Hence during the day when the land gets heated quickly, water takes longer time and remains cool. Therefore, during the day time a land gets more heat than the surrounding water bodies.
d. Ocean currents: It increase or decrease the temperature of the Earth’s surface. Warm ocean currents along the coast make the coastal areas warmer and cold currents reduce the temperature and cool the coastal areas.’ Warm currents can be noticed on the eastern margins of the continents in the middle latitude, while .it is the concurrents flow at the western margins of the continents. Gulf stream a warm currents increases the temperature in the eastern coast of U.S.A and California bold current decreases the temperature of the western coast of U.S.A.
e. Winds: Winds that blow from the lower latitudes are warm and make the places warmer. On the other hand, winds that blow from the higher latitudes are cold and make the places cooler. Winds that blow from the sea bring plenty of rain especially if they are warm winds. While off shore winds hardly bring any rain.
f. Clouds: During the day clouds prevent Insolation from reaching the Earth’s surface. Clouds also prevent three escape of terrestrial’s radiation during the night. Clear sky Permits insolation readily during the day time and allow the rapid escape of terrestrial radiation during the night.
Explain the pressure belts of the world with neat diagram.
The distribution of pressure is not equal on the earth’s surface. It changes from palace to place and time to time on the basis of air temperature and rotation of the earth. Any area in the atmosphere where air pressure is higher than in the surrounding areas is called “ High pressure”/ Thee are 4 high pressure belts and 3 low pressure belts on the earth’s surface.
Equatorial Low pressure belt: This belt lies between latitudes 5° N and 5° S. The Sun’s rays are almost vertical on the equator throughout the year. As a result, the temperature is uniformly high and pressure is low throughout the year. It is also known as “Doldrums”. The air gets warm and rises upward. Horizontal movement of air is absent and convectional currents occur. This is the zone of convergence of the trade winds.
Sub tropical high pressure belts: The air ascended in the form of convectional currents from the equatorial region partly descends in the between 30 to 40’ latitudes in both the hemispheres. The descending air has thus formed two high pressure zones known as subtropics high pressure belts. It is the zone from which trade and anti-trade winds originate. This belt is also known as “ horse altitudes’. It is dry and quite stable. The name horse latitude is given by the ancient sailors who used to transport horses on ships. Due to absence of strong winds, some times the ship could not move with horses. Hence sailors used to dump horses to make the ship move forward.
Sub Polar low pressure belts: In between polar high pressure knd sub-tropical high pressure belt, the sum-tropical low pressure belts are situated. They lies in between 60’ to 70’ latitudes in both the hemispheres. They are formed with spinning action of rotation of the earth and also uprising air as an effect of incoming cold polar winds.
Polar high pressure belts: The Polar Regions are characterized with low temperature. The air raised at the equator descends around the poles causing high pressure belts. The cold polar winds blow outward from this zone.
What is wind? Explain the planetary winds with diagram.
The horizontal movement of air over the Earth surface is called Wind.
Winds which blow from high pressure belts to the low pressure belts in the same direction through out the year are called planetary winds, permanent winds or prevailing winds. Characteristics: The chief characteristics of planetary winds:
a. They are connected with the pressure belts. So they blow from the high pressure belt or area to the low pressure belt or area.
b. They are regular through out the year.
c. They deflect to their right in the northern hemisphere and to their left in the southern hemisphere.
d. As a result of the shifting of the pressure belt northward in summer and southward in winter, the planetary winds also shift northwards in summer and southwards in winter. They are permanent and blow over vast areas of the globe. These winds include trade winds, westerlies and polar winds.
1. Trade winds: The winds that blow in the tropics form the sub-tropical high pressure belts towards the equatorial low pressure belt are called “Trade winds”. They found approximately between 8° and 30° latitudes on both sides blowing from the east. They are also known as “Tropical Easterlies”.
The trade winds due to the law of deflection blow from the north-east in the northern hemisphere and from south-east in the southern hemisphere. Trade winds blow from the cooler sub-tropical areas to the hotter area, hence they do not bring rain. However, when they blow over the open sea they gather moisture and bring heavy rainfall to the east coast of the continents.
2. Anti trade winds: The wind blowing from sub-tropical high pressure belts towards sub-polar low pressure belts are known as anti-trade winds. They are south-west to north east in the northern hemisphere and Norwest to south-east in the southern hemisphere.
Hence they are called ‘Westerlies”. They prevail largely between 40° and 650 north and south of the equator. They blow from the north-west in the southern hemisphere and south – west in the northern hemisphere. As they blow from hotter areas to colder areas they bring rain through the year.
3. Polar winds: Winds blowing from polar high pressure belts toward the sub-polar low pressure belts are known as polar winds. They blow from the north east in the northern hemisphere and south east in the southern hemisphere. As they blow form the snow cov4red areas they are very cold winds. They are constant in the southern hemisphere.
What is conservation of ocean? Mention the measures of conservation of ocean.
Conservation of ocean means rational uses of ocean resources. So that a harmony between man’s ocean resource requirements and their availability could be maintained. The rational uses of ocean resources by the present generation and the preservation of ocean resources for the future generations, is known as conservation of ocean. It also means the protection of oceans and ocean resources against pollution caused by dumping of oceans and of industrial, agricultural and municipal wastes into oceans by man, oil spill from oil tankers, and nuclear explosions in sea and oceans.
Need for conservation of Oceans: There is a need for conservation of oceans due to the following reasons:
- If oceans are not conserved, all the living organism in the oceans either die or become unsuitable for human consumption.
- Oceans are the storehouse of pearls, corals and sponges. These resources have to be conserved.
- Oceans have oil and natural gas reserves. These reserves have to be conserved.
- Oceans are rich in minerals. These mineral resources have to be rationally exploited.
- Oceans allow the growth of innumerable species of plants. These plants have to be conserved.
- Oceans are the breeding centers of marine fisheries. Thousands of fishes are found in oceans. The marine fishery resources should be exploited rationally.
- Literacy and education programmes on marine features must be initiated and promoted.
- Proper law to be enacted to save sea and ocean.
World wise awareness programme must be arranged to show the pro and cons of the marine pollution etc.
Divide India into Physical divisions and explain and explain the Himalayan Mountains.
India is characterized by great diversity in its physical features. On the basis of physiography, the country is divided in to four major physical divisions. They are:
- The Northern Mountains
- The Northern Plains
- The Peninsular Plateau
- The Coastal Plains and Islands
The Himalayas: This is loftiest and snow covered mountains in the world. The area occupied by the Himalayas was earlier a part of ‘Tethys Sea’. The formation of this mountain is by tectonic forces of Gondawana land Angara land masses. It is situated to the north of the Indus and Ganga and the Brahmaputra plains.. The slopes of the Himalayas are gentle towards the north and steep towards south.
The Himalayas have distinct characteristics of high relief, snow covered peaks, complex geographical structures, parallel separated by deep valleys and rich temperate vegetation.The Himalayas are classified into three parallel ranges based on altitude and latitude.
The Great Himalayas or Himadri The lesser Himalayas or Himachal The Outer Himalayas or Siwaliks.
a. The Great Himalayas or Himadri: These are the inner most loftiest and continuous ranges of mountains. The average height of the Great Himalayas is 6200 m and the width varies between 120 and 190 km. The important peaks of great Himalayas in India are, Kanchenjunga-8598m in Sikkim, Nanga Prabat-8126m, Nandadevi, Badrinath, Karmet, Trishuletc.
b. The lesser Himalayas or Himachal: These ranges are also known as Inner Himalayas or Himachal ranges. It is situated between great Himalayas inn the north and Outer Himalayas or Siwaliks in the south. Its average height is around 1500-4500m and the width is about 60 to 80 km. These are very rugged and complex ranges due to erosion by rivers. The important ranges in Lesser Himalayas are Pirpanjal, Dhaul Dhar and nag- tiba etc. The important Hill stations are Shimla, Musooire, Ranikeht, Nainital, Almora, Chakrata, Darjeeling etc. Kulu valley, Kangra valley, Spiti valley are the famous valleys of Himachal.
c. The Outer Himalayas or Siwaliks: These are the outer most ranges situated to the south of Lesser Himalayas, known as Siwaliks. The Siwaliks extend from Jammu & Kashmir in the North West to Arunachal Pradesh in east. The average height of this range is around 600-1500m and its width varies between 15-5Qklm. The siwaliks are formed from the sediments brought down by the rivers of lesser, and Greater Himalayas.
There are flat floored structure valleys between Siwaliks and Lesser Himalayas, Known as Siwaliks. The Siwaliks extend from Jammu&Kashmir in the North West to Arunchal Pradesh in east.
Briefly explain the importance of Inter-linking of rivers of India.
The distribution of rainfall in India is highly uneven and seasonal. The Himalayan rivers are perennial while the peninsular rivers are seasonal. During rainy season, much of the water is lost in floods and wasteful flow into the sea. But in other seasons there is scarcity of water.
Even in India some parts get more rainfall and some other parts get very low rainfall. Consequently there are floods in one region and drought and famine in other regions in the country. The problems of floods and drought can be minimized through the inter-river linkages or through national water grid, under which water from one river basin can be transferred to another river basin for optimum utilization.
The inter-link would consist of two parts, a northern Himalayan River Development component and a southern peninsular river development component. The northern component would consist of series of dams built along the Ganga and Brahmaputra rivers in India, for the purposes of storage, canals would be built to transfer surplus water from the astern tributaries of the Ganga to the west. The Brahmaputra and its tributaries would be linked with the Ganga and the Ganga with the Mahanadi river. This part of the project would provide additional irrigation and generate electricity.
Explain the southwest monsoon winds of India with diagram.
The south-west monsoon winds as starts in June and ends in mid-September. It is also known as advancing monsoon season or rainy season. During this season, India gets more than 75% of its annual rainfall and more than 90% of the country’s area receives downpour. It is the prime season for Kharif crops.
In the middle of June the direct rays of the Sun fall on tropic of caner due to shift in the position of the Sun from Equator towards northern hemisphere. Therefore, there is an increase in temperature from south to north. The temperature in the main land of India and nearby land masses is high compared to water bodies of the Indian Ocean.
a. The Arabian Sea branch: The Arabian Sea branch of the south-west monsoon strikes the western coast of India in Kerala on the 1st June. Arabian sea winds by carrying more moisture blow along the western coast of India and cause heavy rainfall in the western part of Western Ghats due to obstruction. These winds behave like sea breeze and cause continuous rainfall I the wind ward side of the Western Ghats tHl they lose their moisture.
Agumbe of Karnataka receives the highest rainfall during this season. This regions coming under southeast monsoon winds receive good rainfall wherever they get obstruction by hills and plateaus.
b. The Bay of Bengal branch blow from water bodies towards the Indian mainland due to variation in pressure. These winds carry moisture form the Bay of Bengl and blow along eastern coast and finally reach north eastern hills. In its path, whenever this wind receives obstruction, they cause good rainfall. The eastern part of Eastern Ghats and north astern hills receive heavy rainfall. These winds after crossing eastern coast merge the Arabian sea winds.
The Arabian Sea and the Bay of Bengal winds, after merging, blow towards north eastern regions of India. The shape of the Himalayan Mountains and northeastern hills greatly obstruct these winds. Therefore the Meghalaya plateau region, particularly Nokrek areas of Mawsynram and cheerapunji, receive very high rainfall. This place is popularly called Rainiest or wettest place on the Earth.
The southwest monsoon after crossing northeastern region blow towards east. Since the Himalayas obstruct these winds they have to take westerly direction and blow along the foothills of Himalayas. The shift in the direct6 sun rays from Tropic of Cancer towards Equator results in the gradual disappearance of southwest monsoons. Indian economy depends on the Monsoons to a large extent.
Explain the erosion and conservation of soil.
These forests are found in the regions of heavy rainfall (above 250 cm) and high temperature (above 27° C) Tall umbrella shaped trees with dense assemblage is a prominent feature of this forest. The evergreen forests always look green because, various species of trees are found here and they shed leaves in different seasons.
IV. Answer any one of the following. (1 × 10 = 10)
Explain the structure and composition of the earth with a neat diagram.
On the basis of the physical and chemical properties of the earth’s surface, behavioral patterns of seismic waves of earthquakes and the lava erupted form volcanoes, it is generally held that the earth is composed of three layers or parts.
1. The crust: The outer or upper most layer of the earth is the crust. It is solid and is the thinnest and lightest part. It is 6to 60 kms thick. It has two layers.
a. Continental crust or sial: The upper part consist of sedimentary and granite rocks’ and forms the continents. Its major constituent elements are silica and aluminum. So, it is termed as sial. Its average thickness ranges between 10-12 km.
b. Oceanic crust or Sima: The lower part of other Crust is known as oceanic crust. Its thickness is around 5 km. This layer is rich in silica and Magnesium. Therefore, it is called Sima. The lower continuous layer is mostly composing of silica and magnesium and so it is termed as sima. The mean density of this layer is 2.95gm. Conrad discontinuity between Sial and Sima and Mohorovicic discontinuity between Crust and Mantle are the major discontinues in the crust.
2. The Mantle: The portion of the earth’s interior, lying beneath the crust and above the core is known as mantle. It is largely made up of basic silicates, rich in iron and magnesium. It extends from 60 to 2,900km. The density of this layer from 3.3 to 5.7gm. The mantle has two parts.
a. Upper Mantle: This is the outer layer of the Mantle known as Asthenosphre. Most of the earthquakes and volcanoes take birth due to disorder in this layer.
b. Lower Mantle: This is the lower layer of the Mantle known as Mesosphere and it is in solid form. Repetti discontinuity between Asthenosphere and Mesosphere and Gutenberg discontinuity between Mantle and Core are the major discontinues in the mantle
3. The core: The core is the central part of the earth’s interior. It extends from the lower boundary of the mantle to the centre of the earth for about 6,400 kms. The most important materials of core are nickel and ferrous (Nife). The core consists of two layers, namely.
a. Outer core: It is the outer layer of the Core consisting hard molten rocks. Most of the materials are in molten form. It extends from 2900km to 4980km.
b. Inner core: It is the lower layer of the Core with very high temperature and pressure. Most of the materials are in solid form therefore, it is called solid core. The average temperature of this layer is around 2900° C. Transition discontinuity is found between Outer. Core and Inner Core.
What, is a river? Explain the landforms created by the work of a river with neat diagrams.
River is an important external agent of denudation on the ever-changing face of the Earth. The work of river is more or less common in all the drainage systems of the world.
The work of river consists of three closely interrelated activities.
1. Erosional work: The process of wearing and taking away the part of rock is known as ‘Erosion’. It depends upon the volume and velocity of water, nature of slope and the nature of rocks. The erosional work of the river is performed in two ways.
a. The Mechanical and b. The Chemical erosion.
There are various landforms associated to erosional work of river.
a. ’V’ Shaped valley: In the mountain course the speed of the river is greater and volume is less. As the water rushes down the steep slopes there is maximum vertical , or later erosion. The rapid down cutting or vertical erosion results in the formation of ‘V’shaped valley.
b. Gorge: A deep and narrow valley with steep rocky, sides in the river course is known as ‘Gorge’. They are formed by the regular vertical cutting by the rivers in the valleys eg. Narmada gorge.
c. I shape valley: Avey steep, deep river valley formed by the river, lookinglike T, is called ‘I’ Shaped valley. These are very deep compared to gorges.
d. Canyon: It is a wide, deep and steep valley almost with vertical walls like feature found in the arid or semi arid regions is called ‘Canyon’ eg. Grand Canyon of River Colorado in USA.
e. Potholes: These are the small depressions in the rocky beds of other river valley. They are formed by corrosion. Pebbles, sand and small rocks carried by the river swirled around on the river bed. This action erodes the rock on the river bed forming potholes.
f. Waterfalls: Huge volume of water falling from a great height along the course of a river is called “Waterfalls’. They are formed when the hard and soft rocks come in the way of flowing river. The soft rock gets eroded faster and hard rock does not erode easily. Therefore huge amount of water falls from great height and creates waterfalls. Eg. The Jog falls, The Angel falls, The Victoria falls.
g. River Capture: It is formed mainly due to head-ward erosion by the river near its source. When the source of a river is captured by another major and strong river it is called‘River Capture’.
2. Transportational work: The process of carrying away the eroded materials is known as ‘Transportation’. The rock materials and eroded particles carried by a river is called its Load. The transportation capacity of a river is based on velocity of water, volume of water, load, slope, smooth valley floor etc.
The major landforms associated with the transportational work of the river are:
a. Alluvial fans: The term alluvium refers to the debris transported and deposited by rivers. When the fast flowing river enters the plateau or plain region, it experience sudden decline in gradient and obstruction in its path. Due to obstruction of the river spreads and deposits many of its light materials in fan shape known as ‘alluvial fans’.
b. Alluvial cones: In the plateau and foot hill region when the river spreads out, the eroded materials carried by the river is deposited in conical shape called ‘Alluvial cones’.
3. Depositional work: The process of carrying and accumulating the eroded materials by the river at the lower course is called ‘deposition’. In the lower course due to gentle slope the river slows down and deposits most of its materials on the banks, course and the mouth.
The important landforms resulting from depositional work of the river are:
a. Meanders: In the lower course, river flows slowly in zig zag or curved manner due . to smaller obstruction in its path. A curve or loop formed by the river in its path is called ‘Meander’. When the river course formed by such crescent shaped loops due to continuous lateral deposition it is called meandering course.
b. Ox-bow Lakes: The ox-bow lakes are formed by depositional and erosional actions taking place simultaneously and they are a result of excessive meandering. The River which flows through the shorter route leaving the curve of the meander cut off and crescent shaped lake is formed known as‘Ox-bow lakes’.
c. Flood Plains: When the river is in floods the water overflows on its bank and spreads in the surrounding regions. The silt carried by the water gets deposited in these areas and creates flat plains on both the banks of the rive known as ‘Flood Plains’.
d. Delta: A triangular shaped alluvial deposition forced at the mouth of the river is called ‘Delta’. Important types of deltas are
a. Arcuate or Common delta
b. Bird-foot delta
e. Distributaries: As the river approaches the sea or Ocean, due to reduction in gradient, joining of tributaries, its volume increases, speed decreases hence, the rivet begins to break up into a number of branches from the main river called ‘Distributaries’.
f. Estuary: Estuaries are the tidal mouth of a river having a narrow, gradually widening lay at the mouth. In Estuary River water is mixed with seawater. Eg. The Narmada estuary, The Kali estuary.
V. A. Answer the following in a sentence each : (5 × 1 = 5)
What is Cartography?
The Systematic study and practice of making maps.
What is Map?
A part or whole of the Earth drawn on a paper according to scale is called a map.
What is a scale?
A scale is a ratio between any two points on the ground surface and their.corresponding distance on the map.
What is a large scale map?
The Map that are drawn on the scale of 1 cm = 1 km or 1: 1,00,000 is known as large scale maps.
Give examples for small scale map.
Atlas and wall maps.
B. Write the latitude and longitude for the given places. (5 × 1 = 5)
12° 51’ Nto 74°50’ E
Question 43. Bengaluru
13° N to 77°35’ E
15° 52’ N to 74°30’ E
12° 18’ N to 76°38’ E
15° 21’ N to 75°10’ E
C. Draw diagram to the following. (2 × 2 = 4)
Various types of landforms are produced by the volcanoes. They can be grouped into
- Extrusive landforms
- Intrusive landforms
1. Extrusive landforms: The landforms which have been formed due to the accumulation and solidification of lava and other materials given out by volcanoes are known as extrusive landforms. The important extrusive land forms are:
a. Volcanic cones: volcanic cones are the most typical form of extrusive features or landforms.
The lava and other ejected materials that reach the surface of the earth are accumulated around the crater, and cones are formed. The formation of cones depends jupon the nature of explosion and the materials emitted out of it. There fore, cones are various types. They are:
- Cinder cones: A volcanic cone formed by volcanic cinder accumulated around the crates is called cinder cone.
- Ash cone: A cone shaped hill formed by of volcanic ash that is built up around a volcanic ent is called ash cone.
- Composite cone: A volcanic cone composed of alternative layers of ash, cinder and lava is called composite cone.
- Parasite cone: Some times, many smaller cones are developed in the neighborhood of the main cone. They are called parasite cone.
b. Crater: A crater is pit at the top of volcanic vent, during volcanic eruption, materials form the top of the cone are blown off and a bowl- shaped depression is formed. It is known as crater.
Caldera: Sometime a violent explosion blow away the original cone and forms a large basin-shaped depression called caldera
Volcanic spine: The acid lava, which is vicious, solidifies quickly and blocks the vent. This stands up as a steep-sided cone called spine or plug.
Lava dome: The shape of lava dome is determined by the nature of lava. The highly fluid basic lava builds up shield dome with gently rising slopes, and flattened top. The basic lava, which is highly viscous, builds up dome with a great height and steep slope
Lava plateau: An extensive elevated land made up of depositional lava called lava plateau.
2. Intrusive land forms: Intrusive landforms occur when lava solidifies with the earth’s. crust and gives rise to various shapes or forms. Intrusive landforms are formed along the bedding planes of sedimentary rocks. There are various forms of intrusive landforms. They are:
Dyke: The Magma from the interior of the earth finds its way towards the surface through a passage. When it is able to reach the surface, it cools and solidifies, and a vertical or highly inclined feature is formed, and such a features is called dyke.
Sill: A sheet of magma which lies along the bedding plan is called sill.
Laccolith: Laccolith is a large mound of igneous rock formed along a bedding plane in the sedimentary rock layers.
Batholith: Batholith is a very large dome – shaped intrusion of igneous rock. It is exposed to the surface only after considerable erosion.
Hot springs or thermal spring’s are more common. The water sinks deep inside where the rocks are heated. The heated water rises to the surface without any explosion. Such springs contain dissolved minerals which are of medicinal value. They can be also used to generate electricity. Iceland has thousands of hot springs. A Geyser is a hot spring form which a column of hot water and stream are alternatively ejected to a great height.
D. Draw the outline map of India, mark and name the following (2 × 3 = 6)
Draw the map of India
Physical divisions of India
Flood-prone regions of India
Forests in India
Western Ghats and Eastern Ghats.
Rivers and Lakes