Attempt any 14 questions
Q.1. ____________ is used in jewellery. It is usually a greenish crystal, often found in basaltic rocks.
Q.2. The land building forces are known as the:
(a) endogenic forces
(b) exogenic forces
(c) geomorphic forces
Q.3. Fill in the blanks: Geography helps in understanding the reality in its_________ perspective.
Q.4. The total assemblage of plant and animal species interacting within specific conditions is known as:
(c) flow of energy
(d) food chain
Q.5. Arrange the correct sequence of column II against the column I
(a) III – 1, IV – 2, I – 3, II – 4
(b) I – 4, II – 3, III – 2, IV – 1
(c) IV – 3, I – 4, II – 1, III – 2
(d) II – 2, III – 1, IV – 4, I – 3
Q.6. The trees reach great heights up to 60 m or above in the:
(a) Mountain forests
(b) Swamp forests
(c) Tropical evergreen forests
(d) Montane forests
Q.7. A region with a large number of deep gullies or ravines is called a:
(a) good land topography
(b) bad land topography
(c) arid land topography
(d) sandy land topography
Q.8. The largest Peninsular river system is the:
Q.9. Fill in the blanks :
____________ is essential to the survival of all organisms.
Q.10. Geography should be studied as an:
(a) integrated subject
(b) independent subject
(c) intermingled subject
(d) interlocked subject
Q.11. The earth’s radius is:
(a) 6,370 km
(b) 7,370 km
(c) 8,370 km
(d) 9,370 km
Q.12. The Continental Drift Theory was given in:
Q.13. S-waves are also known as:
(a) primary waves
(b) secondary waves
(c) major waves
(d) minor waves
Q.14. Arthur Holmes discussed the possibility of convection currents operating in the mantle portion in:
Q.15. Bio refers to the:
(a) non-living beings
(b) living beings
Q.16. Study the given graph carefully and answer the following questions:
Answer any three questions:
(a) According to the graph the precipitation is highest in which of the following forest zones?
(b) According to the graph, which of the following forest zones has the highest temperature?
(c) According to the graph, which of the following zones has a zone of dominance of oxides of aluminium?
(d) Clay mineral zone is found in:
Q.17. Read the Case Study given below and answer the questions that follow:
Erosion involves acquisition and transportation of rock debris. When massive rocks break into smaller fragments through weathering and any other process, erosional geomorphic agents like running water, ground water, glaciers, wind and waves remove and transport it to other places depending upon the dynamics of each of these agents. Abrasion by rock debris carried by these geomorphic agents also aids greatly in erosion. By erosion, relief degrades, i.e., the landscape is worn down. That means, though weathering aids erosion it is not a precondition for erosion to take place. Weathering, mass-wasting and erosion are degradational processes. It is erosion that is largely responsible for continuous changes that the earth’s surface is undergoing. Denudational processes like erosion and transportation are controlled by kinetic energy. The erosion and transportation of earth materials is brought about by wind, running water, glaciers, waves and ground water. Of these the first three agents are controlled by climatic conditions. They represent three states of matter —gaseous (wind), liquid (running water) and solid (glacier) respectively.
The work of the other two agents of erosion-waves and ground water is not controlled by climate. In case of waves it is the location along the interface of litho and hydrosphere — coastal region — that will determine the work of waves, whereas the work of groundwater is determined more by the lithological character of the region. If the rocks are permeable and soluble and water is available only then karst topography develops. Deposition is a consequence of erosion. The erosional agents lose their velocity and hence energy on gentler slopes and the materials carried by them start to settle themselves. In other words, deposition is not actually the work of any agent. The coarser materials get deposited first and finer ones later. By deposition depressions get filled up. The same erosional agents viz., running water, glaciers, wind, waves and ground water act as aggradational or depositional agents also.
Answer any three questions:
(a) What is largely responsible for continuous changes that the earth’s surface is undergoing:
(b) Denudational processes like erosion and transportation are controlled by which of the following?
(i) Kinetic energy
(ii) Potential energy
(iii) Solar energy
(iv) None of these
(c) The work of two agents of erosion-waves and ground water is not controlled by :
(iv) None of the above
(d) If the rocks are permeable and soluble and water is available only then _______ topography develops.
Q.18. What is the significance of weathering?
Ans: Significance of weathering:
(i) Weathering processes are responsible for breaking down the rocks into smaller fragments and preparing the way for formation of not only regolith and soils, but also erosion and mass movements.
(ii) Biomes and biodiversity is basically a result of forests (vegetation) and forests depend upon the depth of weathering mantles.
(iii) Weathering of rocks and deposits helps in the enrichment and concentrations of certain valuable ores of iron, manganese, aluminium, copper etc., which are of great importance for the national economy. Weathering is an important process in the formation of soils.
Q.19. What do you know about the innermost layer of the earth?
Name the major and minor plates into which the Earth has been divided.
(i) The innermost layer of the earth is known as the core.
(ii) The earthquake wave velocities helped in understanding the existence of the core of the earth. The core-mantle boundary is located at the depth of 2,900 km.
(iii) The outer core is in liquid state while the inner core is in solid state. The density of material at the mantle-core boundary is around 5 g/cm3 and at the centre of the earth at 6,300 km, the density value is around 13 g/cm3.
(iv) The core is made up of very heavy material mostly constituted by nickel and iron. It is sometimes referred to as the nife layer.
The major plates are as follows:
(i) Antarctica and the surrounding oceanic plate
(ii) North American (with western Atlantic floor separated from the South American plate along the Caribbean islands) plate
(iii) South American (with western Atlantic floor separated from the North American plate along the Caribbean islands) plate
(iv) Pacific plate
(v) India-Australia-New Zealand plate
(vi) Africa with the eastern Atlantic floor plate
(vii) Eurasia and the adjacent oceanic plate
Some of the minor plates are:
(i) Cocos plate: Between Central America and Pacific plate
(ii) Nazca plate: Between South America and Pacific plate
(iii) Arabian plate: Mostly the Saudi Arabian landmass
(vi) Philippine plate: Between the Asiatic and Pacific plate
(v) Caroline plate: Between the Philippine and Indian plate (North of New Guinea)
(vi) Fuji plate: North-east of Australia.
Q.20. Explain the hypothesis, known as the “sea floor spreading” given by Hess?
Harry Hess argued that constant eruptions at the crest of oceanic ridges cause the rupture of the oceanic crust and the new lava wedges into it, pushing the oceanic crust on either side. The ocean floor, thus spreads. The younger age of the oceanic crust as well as the fact that the spreading of one ocean does not cause the shrinking of the other, made Hess think about the consumption of the oceanic crust. He further maintained that the ocean floor that gets pushed due to volcanic eruptions at the crest, sinks down at the oceanic trenches and gets consumed.
Q.21. Differentiate between conduction and convection.
Depending upon the mode of formation, sedimentary rocks can be classified into how many groups?
Depending upon the mode of formation, sedimentary rocks are classified into three major groups:
(i) Mechanically formed: Sandstone, conglomerate, limestone, shale, loess, etc., are some of the examples.
(ii) Organically formed: Geyserite, chalk, limestone, coal, etc., are some of the examples.
(iii) Chemically formed: Chert, limestone, halite, potash etc., are some of the examples.
Q.22. What do you know about the Indus River System?
Ans: The Indus River System:
(i) It is one of the largest river basins of the world, covering an area of 11,65,000 sq. km (in India it is 321, 289 sq. km and a total length of 2,880 km (in India 1,114 km). The Indus also known as the Sindhu, is the westernmost of the Himalayan rivers in India. It originates from a glacier near Bokhar Chu (31°15' N latitude and 81°40' E longitude) in the Tibetan region at an altitude of 4,164 m in the Kailash Mountain range.
(ii) The Indus receives a number of Himalayan tributaries such as the Shyok, the Gilgit, the Zaskar, the Hunza, the Nubra, the Shigar, the Fasting and the Dras. It finally emerges out of the hills near Attock where it receives the Kabul river on its right bank.
(iii) The river flows southward and receives ‘Panjnad’ a little above Mithankot. The Panjnad is the name given to the five rivers of Punjab, namely the Satluj, the Beas, the Ravi, the Chenab and the Jhelum. It finally discharges into the Arabian Sea, east of Karachi. The Indus flows in India only through the Leh district in Jammu and Kashmir.
Q.23. Discuss the various sources of information related to the interior of the earth.
Ans: Most of our knowledge about the interior of the earth is largely based on estimates and inferences. Yet, a part of the information is obtained through indirect and direct observations and analysis of materials. Various sources of information are:
(i) Mining: The most easily available solid earth material is surface rock or the rocks we get from mining areas. Gold mines in South Africa are as deep as 3 - 4 km. Going beyond this depth is not possible as it is very hot at this depth. Through mining precious stones, rocks and fuels are extracted which gives us valuable information.
(ii) Drilling: Scientists have taken up a number of projects to penetrate deeper depths to explore the conditions in the crustal portions. Scientists world over are working on two major projects such as “Deep Ocean Drilling Project” and “Integrated Ocean Drilling Project”. The deepest drill at Kola, in the Arctic Ocean, has so far reached a depth of 12 km. This and many deep drilling projects have provided large volumes of information through the analysis of materials collected at different depths.
(iii) Volcanic eruptions: Volcanic eruption forms another source of obtaining direct information. As and when the molten material (magma) is thrown onto the surface of the earth, during volcanic eruptions it becomes available for laboratory analysis. However, it is difficult to ascertain the depth of the source of such magma. To know about the thickness of the earth, scientists have estimated the values of temperature, pressure and density of materials at different depths.
(iv) Meteors that reach the Earth: Another source of information are the meteors that at times reach the earth. However, it may be noted that the material that becomes available for analysis from meteors, is not from the interior of the earth. The material and the structure observed in the meteors are similar to that of the earth. They are solid bodies developed out of materials same as, or similar to, our planet. Hence, this becomes yet another source of information about the interior of the earth.
(v) Gravitation: The gravitational force (g) is not the same at different latitudes on the surface. It is greater near the poles and less at the Equator. This is because of the distance from the centre at the equator being greater than that at the poles. The gravity values also differ according to the mass of material. The uneven distribution of mass of material within the earth influences this value. The reading of the gravity at different places is influenced by many other factors. These readings differ from the expected values. Such a difference is called gravity anomaly. Gravity anomalies give us information about the distribution of mass of the material in the crust of the earth.
(vi) Magnetic surveys: Magnetic surveys also provide information about the distribution of magnetic materials in the crustal portion, and thus, provide information about the distribution of materials in this part.
(vii) Seismic activity: It is one of the most important sources of information. The seismic waves provide a complete picture of the layered interior.
Q.24. Discuss the evidence available in support of the Continental Drift Theory.
Explain any five physical characteristics of the minerals.
Ans: Evidences in support of Continental Drift Theory are as follows:
(i) The Matching of Continents (Jig-Saw-Fit): The shorelines of Africa and South America facing each other have a remarkable and unmistakable match. It may be noted that a map produced using a computer programme to find the best fit of the Atlantic margin was presented by Bullard in 1964. It proved to be quite perfect. The match was tried at 1,000 fathom lines instead of the present shoreline.
(ii) Rocks of Same Age Across the Oceans: The radiometric dating methods developed in the recent period have facilitated correlating the rock formation from different continents across the vast ocean. The belt of ancient rocks 2,000 million years from Brazil's coast matches those from western Africa. The earliest marine deposits along the coastline of South America and Africa are of the Jurassic Age. This time.
(iii) Tillite: It is the sedimentary rock formed out of deposits of glaciers. The Gondwana System of sediments from India is known to have its counterparts in six different landmasses of the Southern Hemisphere. At the base the system has thick tillite indicating extensive and prolonged glaciation. Counter parts of this succession are found in Africa, Falkland Island, Madagascar, Antarctica and Australia besides India. Overall resemblance of the Gondwana type sediments clearly demonstrates that these landmasses had remarkably similar histories.
(iv) Placer Deposits: The occurrence of rich placer deposits of gold in the Ghana coast and the absolute absence of source rock in the region is an amazing fact. The gold bearing veins are in Brazil and it is obvious that the gold deposits of Ghana are derived from the Brazil Plateau when the two continents lay side by side.
(v) Distribution of Fossils: When identical species of plants and animals adapted to living on land or in fresh water are found on either side of the marine barriers, a problem arises regarding accounting for such distribution. The observations that Lemurs occur in India, Madagascar and Africa led some to consider a contiguous landmass “Lemuria'' linking these three landmasses.
The five physical characteristics of the minerals are:
(i) External crystal form: Determined by internal arrangement of the molecules—cubes, octahedrons, hexagonal prisms, etc.
(ii) Cleavage: Tendency to break in given directions producing relatively plane surfaces—result of internal arrangement of the molecules—may cleave in one or more directions and at any angle to each other.
(iii) Fracture: Internal molecular arrangement so complex there are no planes of molecules; the crystal will break in an irregular manner, not along planes of cleavage.
(iv) Lustre: Appearance of a material without regard to colour; each mineral has a distinctive lustre like metallic, silky, glossy, etc.
(v) Colour: Some minerals have characteristic colour determined by their molecular structure— malachite, azurite, chalcopyrite etc., and some minerals are coloured by impurities. For example, because of impurities quartz may be white, green, red, yellow, etc.
(vi) Streak: Colour of the ground powder of any mineral. It may be of the same colour as the mineral or may differ—malachite is green and gives green streak, fluorite is purple or green but gives a white streak.
(vii) Transparency: Transparent: light rays pass through so that objects can be seen plainly; translucent—light rays pass through but will get diffused so that objects cannot be seen; opaque— light will not pass at all.
(viii) Structure: Particular—arrangement of the individual crystals; fine, medium or coarse grained; fibrous—separable, divergent, radiating.
(xi) Hardness: Relative resistance being scratched; ten minerals are selected to measure the degree of hardness from 1-10. They are: 1. talc; 2. gypsum; 3. calcite; 4. fluorite; 5. apatite; 6. feldspar; 7. quartz; 8. topaz; 9. corundum; 10. diamond. Compared to this for example, a fingernail is 2.5 and glass or knife blade is 5.5.
(x) Specific gravity: The ratio between the weight of a given object and the weight of an equal volume of water; object weighed in air and then weighed in water and divided in air by the difference of the two weights.
Q.25. Name the various types of chemical weathering processes.
Explain the heating and cooling mechanism of the atmosphere.
Ans: The various types of chemical weathering processes are:
(i) Solution: When something is dissolved in water or acids, the water or acid with dissolved contents is called solution. This process involves removal of solids in solution and depends upon solubility of a mineral in water or weak acids. On coming in contact with water many solids disintegrate and mix up as suspension in water. Soluble rock forming minerals like nitrates, sulphates, and potassium etc. are affected by this process.
(ii) Carbonation: Carbonation is the reaction of carbonate and bicarbonate with minerals and is a common process helping the breaking down of feldspars and carbonate minerals. Carbon dioxide from the atmosphere and soil air is absorbed by water, to form carbonic acid that acts as a weak acid.
(iii) Hydration: Hydration is the chemical addition of water. Minerals take up water and expand; this expansion causes an increase in the volume of the material itself or rock. Calcium sulphate takes in water and turns to gypsum, which is more unstable than calcium sulphate. This process is reversible and long, continued repetition of this process causes fatigue in the rocks and may lead to their disintegration.
(iv) Oxidation: In weathering, oxidation means a combination of a mineral with oxygen to form oxides or hydroxides. Oxidation occurs where there is ready access to the atmosphere and oxygenated waters. The minerals most commonly involved in this process are iron, manganese, sulphur, etc. In the process of oxidation rock breakdown occurs due to the disturbance caused by addition of oxygen. Red colour of iron upon oxidation turns to brown or yellow.
(v) Reduction: When oxidised minerals are placed in an environment where oxygen is absent, reduction takes place. Such conditions exist usually below the water table, in areas of stagnant water and waterlogged ground. Red colour of iron upon reduction turns to greenish or bluish grey.
The heating and cooling mechanism of the atmosphere includes:
(a) The earth after being heated by insolation transmits the heat to the atmospheric layers near to the earth in long wave form. The air in contact with the land gets heated slowly and the upper layers in contact with the lower layers also get heated. This process is called conduction.
(b) Conduction takes place when two bodies of unequal temperature are in contact with one another, there is a flow of energy from the warmer to cooler body. The transfer of heat continues until both the bodies attain the same temperature or the contact is broken. Conduction is important in heating the lower layers of the atmosphere.
(a) The air in contact with the earth rises vertically on heating in the form of currents and further transmits the heat of the atmosphere. This process of vertical heating of the atmosphere is known as convection.
(b) The convective transfer of energy is confined only to the troposphere.
(a) The transfer of heat through horizontal movement of air is called advection. Horizontal movement of the air is relatively more important than the vertical movement. In middle latitudes, most diurnal (day and night) variation in daily weather are caused by advection alone.
(b) In tropical regions particularly in northern India during summer season local winds called ‘loo’ is the outcome of the advection process.
Q.26. What factors determine the volume of water in a river?
Explain the features of the alluvial soil.
Ans: Factors that determine the volume of water in a river are:
(i) Size of the drainage basin: A drainage basin in an area drained by one main river and its tributaries determines the volume of water in a river. If the drainage basin is large, the volume of water in the river will be more. When the drainage is large the surface runoff flourished the river is more runoff in the amount of rainwater that flows in the ground and ultimately into the river or lake. On the other hand, if the drainage basin is small, the volume of water in the river will be less because there is less surface area for the rain to fall on.
(ii) Vegetation: Leaves of trees intercept rainwater and allow more water to sweep into the ground in groundwater. As a result, the amount of surface runoff reduces. Therefore, the volume of water. in the river is less where vegetation is dense. Spare vegetation prevents rainwater from getting trapped in the leaves and branches, thereby allowing more water to flow through as surface runoff. So in areas with less vegetation volume of water is more.
(iii) Permeability of rocks: In areas with permeable or porous rocks, much of the rainwater sweeps through the pores in the rocks into the ground. In such areas, surface runoff is less and water flowing into the river channel will also be less.
(iv) Climate: In areas with hot and wet climates such as equatorial areas, volume of water in rivers will be high. However, the amount of water will be less in areas with dry climate receiving less rainfall. In areas with prominent wet or dry seasons, volume of water in the river will vary according to the amount of rainfall received.
(v) Riverbed gradient: The gradient of a river refers to how steep its slope is, this also has a significant effect on the velocity of a river. When a river flows down a steep slope, the gravitational force that pulls the water downward is stronger than it would be on water flowing down a gentle slope.
Features of the alluvium soil:
(i) They are depositional soils, transported and deposited by rivers and streams. Through a narrow corridor in Rajasthan, they extend into the plains of Gujarat. In the Peninsular region, they are found in deltas of the east coast and in the river valleys.
(ii) Alluvial soils are widespread in the northern plains and the river valleys. These soils cover about 40 percent of the total area of the country.
(iii) The alluvial soils vary in nature from sandy loam to clay. They are generally rich in potash but poor in phosphorus. In the Upper and Middle Ganga plain, two different types of alluvial soils have developed, viz. Khadar and Bhangar.
(iv) Khadar is the new alluvium and is deposited by floods annually, which enriches the soil by depositing fine silts. Bhangar represents a system of older alluvium, deposited away from the flood plains. Both the Khadar and Bhangar soils contain calcareous concretions (Kankars).
(v) The colour of the alluvial soils varies from the light grey to ash grey. Its shades depend on the depth of the deposition, the texture of the materials, and the time taken for attaining maturity. Alluvial soils are intensively cultivated.
Q.27. Name the important drainage patterns?
Ans: The important drainage patterns are:
(i) Dendritic: The drainage pattern resembling the branches of a tree is known as “dendritic” the examples of which are the rivers of the northern plain like Ganga, Yamuna, etc.
(ii) Radial: When the rivers originate from a hill and flow in all directions, the drainage pattern is known as ‘radial’. The rivers originating from the Amarkantak range and the Central Highlands present a good example of it.
(iii) Centripetal: When the rivers discharge their waters from all directions in a lake or depression, the pattern is known as ‘centripetal’. These rivers form cascades/rapids and waterfalls.
(iv) Trellis: When the primary tributaries of rivers flow parallel to each other and secondary tributaries join them at right angles, the pattern is known as ‘trellis’. Peninsular rivers such as Godavari, Krishna, etc are good examples.
Q.28. Locate and label any five features with appropriate symbols on the given political outline map of India:
(i) The Great Plains of North India
(ii) The Himalayan Mountain
(iii) The Coastal Plains
(iv) The Great Indian Desert
(v) The Island group
(vi) Katni Bauxite Mines
(vii) Neyveli Lignite Coal Field
Q.29. On the outline map of the world mark the following:
(i) West wind drift
(ii) North Atlantic drift
(iii) Brazilian current
(iv) Labrador current
(v) Equatorial counter current