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Karnataka State Syllabus Class 8 Social Science Geography Important Questions Chapter 2 Lithosphere
Question 1.
What is lithosphere?
Answer:
The outermost solid layer of the earth is known as ‘lithosphere’. ‘Litho’ means ‘rock’.
Question 2.
Write a note on lithosphere.
Answer:
The outermost solid layer of the earth is known as lithosphere. This layer is very thick in the continents and quite thin under the sea floor. The lithosphere consists of rocks, minerals, soils, etc. Life exists on this layer with the help of the atmosphere and the hydrosphere. Continents are part of the lithosphere, where different land forms like mountains, plateaus, plains, etc., are found.
Question 3.
Mention the three major layers of the interior of the earth. On what basis are they classified?
Answer:
The interior of the earth is classified into three layers namely the crust, the mantle and the core. These layers are classified on the basis of density of material, chemical composition and physical state of the matter.
Question 4.
Describe the structure of the crust.
Answer:
The crust is the uppermost layer of the earth. It is rich in silica, aluminium and magnesium. The depth of this layer is around 60 kms. from the surface.
Question 5.
What is SIAL?
Answer:
In the upper part of the earth’s crust, only lighter materials are found. It is called SIAL (Silica and Aluminium) or continental crust.
Question 6.
What is SIMA?
Answer:
The lower part of the earth’s crust is rich in silica and magnesium and it is called SIMA or oceanic crust.
Question 7.
What is mantle? Describe its structure.
Answer:
Mantle is the second and the middle layer of the earth. The depth of this layer is up to 2900 kms. from the surface. The materials here are in semi-liquid or partially molten state which is called magma. The mantle is composed of dense and rigid rocks which have predominance of minerals like magnesium and iron.
Question 8.
Which are the two layers of the mantle?
Answer:
The two layers of the mantle are
- the upper mantle also called Asthenosphere, which is partially in molten state and
- the lower mantle or mesosphere which is in solid state.
Question 9.
What is ‘Moho’?
Answer:
The contact zone of the crust and mantle is called ‘Mohorovicic Discontinuity’ or ‘Moho’.
Question 10.
What is Gutenberg Discontinuity?
Answer:
The boundary that separates the mantle from the core is called Gutenberg Discontinuity.
Question 11.
What is‘core’of the earth? Describe its structure.
Answer:
The core is the innermost layer of the earth. The depth of this layer is 6371 kms. from the surface. The most important materials of the core are nickel and ferrous (iron). So, it is also known as NIFE. The core is divided into two sub-layers. The outer core is known as molten core, where the materials are in liquid and molten form. The inner core is in solid form and is known as solid core.
Question 12.
What are rocks?
Answer:
Rocks are the solid inorganic substances that are found in the crust of the earth. They are aggregates of minerals. Rocks are formed due to various natural processes.
Question 13.
What are the different types of rocks?
Answer:
On the basis of mode of formation, rocks are classified into three types. They are
- igneous rocks
- sedimentary rocks
- metamorphic rocks.
Question 14.
How are igneous rocks formed?
OR
Why are igneous rocks called primary rocks?
Answer:
Igneous rocks are those which have been formed by cooling of molten matter of the earth. Igneous rocks were the first to be formed; therefore, they are also called primary rocks.
Question 15.
Which are the different types of igneous rocks?
Answer:
There are two important types of igneous rocks namely, Intrusive rocks and Extrusive rocks. The intrusive rocks are further divided into plutonic and dyke rocks.
Question 16.
What are intrusive igneous rocks? Give examples.
Answer:
When the molten materials (magma) of the earth’s interior do not reach the earth’s surface, they cool and solidify (quite slowly) below the surface. Such rocks are called intrusive igneous rocks. These rocks are made of large crystals and are found at great depth inside the earth. eg: Granite, Diorite and Gabbro.
Question 17.
What are extrusive igneous rocks? Give examples.
Answer:
Rocks formed by solidification of magma above the surface of the earth are known as extrusive igneous rocks. These rocks are generally fine grained or glassy because lava after reaching the surface of the earth cools and solidifies quickly. eg: Basalt and Andesite.
Question 18.
What is lava?
Answer:
The rock material in the liquid or molten state is called ‘magma’ and when it comes out from the earth it is called lava.
Question 19.
How are sedimentary rocks formed?
OR
Why are sedimentary rocks called stratified rocks?
OR
Why are sedimentary rocks called secondary rocks?
Answer:
Sedimentary rocks are formed by the agency of water, wind and ice. These agents break and erode igneous rocks, transport the broken fragments and deposit them at certain places in the form of layers or strata. Therefore, sedimentary rocks are called stratified rocks.
The sedimentary rocks are formed after the disintegration of igneous rocks. Therefore, they are called secondary rocks. These rocks are also called aqueous rocks because they are formed in water bodies like lake, sea or ocean.
Question 20.
How are sedimentary rocks classified?
Answer:
Sedimentary rocks are classified into inorganic and organic rocks. Inorganic rocks are further classified into mechanically formed sedimentary rocks and chemically formed sedimentary rocks. Mechanically formed rocks are again classified into arenaceous rocks and argillaceous rocks. Organically formed sedimentary rocks are classified into calcareous and carbonaceous rocks.
Question 21.
How are sedimentary rocks formed mechanically?
Answer:
Rocks built up by fragments of pre-existing rocks which have been produced by the process of weathering and erosion are the mechanically formed sedimentary rocks. eg: sandstone and shale.
Question 22.
How are sedimentary rocks formed chemically?
Answer:
Chemical sediments are commonly formed by the process of evaporation of water containing salts in solution. eg: rock salt, gypsum, etc.
Question 23.
What are organically formed sedimentary rocks? Give examples.
Answer:
Organically formed sedimentary rocks are those derived by the accumulation of remains of organisms such as shells of marine organisms, remains of plants and animals, etc. eg: limestone and coal.
Question 24.
What are metamorphic rocks? Explain with examples.
Answer:
Metamorphic rocks are those which are formed by the process of metamorphism or alteration of pre-existing rocks. Metamorphism means change of form, which may be physical or chemical or both, due to the influence of heat and pressure. Example: granite changes into gneiss, basalt into schist, limestone into marble, sandstone into quartzite, coal into graphite, and graphite into diamond. Metamorphic rocks are the hardest rocks on earth. These rocks supply precious stones. eg: sapphire, ruby, emerald and diamonds.
Question 25.
Which are the forces that change the surface features of the earth?
Answer:
The earth has two important forces that change the surface features of the earth. They are internal forces and external forces.
Question 26.
What are the internal forces of the earth which change the surface of the earth?
Answer:
The internal forces of the earth which can change the surface of the earth are those forces which originate inside the crust and influence the surface features of the earth. eg: volcanoes, earthquakes, etc. Internal forces are also called Endogenic forces.
Question 27.
Write a note on volcanoes.
Answer:
A volcano is a vent or narrow opening in the earth’s crust connected by a pipe to an underlying magma chamber, through which magma, rock fragments, lava, ash, steam, flames and other gases are emitted from the interior of the earth.
The passage in the earth’s crust through which magma and other volcanic materials are ejected is palled vent. The funnel-shaped hollow at the top of the cone of a volcano is called crater. A large basin-shaped crater bounded by steep sides is known as caldera.
Question 28.
Draw a diagram showing the structure of a volcano and label the parts.
Answer:
Question 29.
Which are the different types of volcanoes?
OR
Name the types of volcanoes on the basis of frequency of eruption.
Answer:
On the basis of the periodicity or frequency of eruption, volcanoes are classified into three types. They are
- Active volcanoes
- Dormant volcanoes
- Extinct volcanoes.
Question 30.
What is meant by active volcano? Give examples.
Answer:
Volcanoes which constantly eject lava, gases, ashes, etc., are known as active volcanoes. Examples are – Mount Stromboli and Mount Etna in Italy, Mount St. Helens in USA, Mauna Loa in Hawaiian Islands, Mount Pinatubo in Philippines, etc.
Question 31.
What is a dormant volcano? Give examples.
Answer:
Dormant volcanoes are those which have erupted in the past and are likely to erupt again but have remained inactive for fairly long periods. Examples are Mt. Vesuvius in Italy, Mt. Fujiyama in japan, Mt. Kilimanjaro in Tanzania, Mt. Krakatoa in Indonesia, etc.
Question 32.
What are extinct volcanoes? Give examples.
Answer:
Extinct volcanoes are those which were active in the remote geological periods. These are not likely to be active again. eg: Ngorongoro in Tanzania, Arthur’s Seat in Scotland.
Question 33.
What are the different materials thrown out by volcanoes?
Answer:
The materials ejecting out from volcanoes are of three types:
- Solid: Volcanic bombs, cinders, scoria, pumice, dust and ash.
- Liquid: Lava.
- Gases: Sulphur, hydrogen and carbon dioxide.
Question 34.
Which are the major volcanic regions?
Answer:
Volcanoes occur in many regions of the world including islands, young mountain ranges and plateaus of continents. However, the Circum-Pacific belt, Mid-Atlantic belt, Mid-Continental belt and islands of Hawaii and Indonesia are major volcanic regions.
Question 35.
What is ‘Pacific Ring of Fire’?
Answer:
Coastal margins of the Pacific Ocean consisting of Philippines, Japan, U.S.A., Central America, South America, etc., form a kind of ring. These areas around the Pacific have many volcanically active regions. Hence, this region is called Pacific Ring of Fire.
Question 36.
What are earthquakes?
Answer:
An earthquake is a shock or series of shocks or tremors due to sudden movement of crustal rocks generated within the crust or mantle.
Question 37.
What is hypocentre?
Answer:
Hypocentre or Seismic focus is the point within the earth (below the earth’s surface) where an earthquake originates.
Question 38.
What is epicentre?
Answer:
Epicentre is the point directly above the hypocentre or seismic focus at the surface of the earth.
Question 39.
What is seismology?
Answer:
The scientific study of earthquakes is called seismology.
Question 40.
How are earthquakes measured?
Answer:
The origin, time, velocity and direction of seismic waves are recorded by an instrument known as Seismograph.
Question 41.
What are the causes of earthquakes?
Answer:
The causes of earthquakes are:
1. Plate tectonics:
The earth’s crust consists of many major and minor plates. These plates are not stationary. The plate boundaries are dynamic places and are the primary location of earthquake activity.
2. Volcanic eruptions:
Volcanic earthquakes are caused by gas explosions.
3. Faulting:
A fault consists of a fracture in the rock along which a great deal of displacement takes place. An earthquake takes place when movement of plates takes place along a line of fracture.
4. Man-made factors:
Over-interaction of man with nature is also one of the main causes of the occurrence of many of the earthquakes. The extraction of minerals, deep underground mining, construction of huge dams and reservoirs, nuclear tests, etc., are some of the causes.
Question 42.
What are earthquake waves? Which are the different types of earthquake waves?
Answer:
The earthquake or seismic waves originate in the seismic focus and travel towards the epicenter in ripples or concentric circles. The three important earthquake waves are:
1. Primary waves:
These are”also called longitudinal or compressional waves. These are the fastest earthquake waves and the first waves to reach the surface. They can pass through solid, liquid and gaseous matters.
2. Secondary waves:
They are also called transverse or distortional waves. These waves cannot pass through liquids. They reach the epicenter after the primary waves.
3. Surface waves:
These are also called long waves. They are the slowest earthquake waves. But, they are responsible for maximum destruction on the surface of the earth.
Question 43.
What are the effects of earthquakes?
Earthquakes are very dangerous and destructive. They cause large-scale deaths, loss of property, landslides, flash floods, damage to roads, bridges, etc.
Question 44.
What scale is used to measure the magnitude of earthquakes?
Answer:
Richter scale is used to measure the magnitude and intensity of earthquakes.
Question 45.
What is Tsunami? How is it caused?
Answer:
Tsunami is a large sea wave caused by an underwater earthquake. In Japanese language ‘Tsunami’ means ‘harbour waves’.
Question 46.
Mention the important earthquake-prone regions of the world.
Answer:
The important earthquake-prone regions of the world are:
- The Circum-Pacific Belt – regions around the Pacific Ocean
- The Mediterranean Belt – regions around the Mediterranean Sea.
- The Himalayan Belt – the Siwalik region of India.
Question 47.
Which are the external forces that modify the surface of the earth?
Answer:
External forces are the natural forces that modify the surface of the earth. The important forces are temperature, wind, rainfall, snowfall, river, glacier, etc. These forces act on the surface of the earth and constantly change its features.
Question 48.
What is weathering? Mention the three types of weathering.
Answer:
Weathering is the wearing away or breaking down or gradual disintegration of rocks by agents present in the atmosphere such as temperature, rainfall, winds, etc. The three types of weathering are – Mechanical weathering, Chemical weathering and Biological weathering.
Question 49.
What is mechanical weathering? Mention its agents.
Answer:
When rocks are broken and disintegrated without any chemical alteration, the process is called physical weathering or mechanical weathering. The important processes of mechanical weathering are granular disintegration, block disintegration and exfoliation. The agents of mechanical weathering are temperature, wind, frost, etc.
Question 50.
What is chemical weathering? Which are the different types of chemical weathering? Explain.
Answer:
Chemical weathering is mainly brought about by the action of substances dissolved in rainwater. This type of weathering results in changing the composition of minerals present in the rocks. There are four types of chemical weathering. They are:
- Oxidation: In this type of chemical weathering oxygen dissolved in water reacts with certain minerals, especially iron, to form oxides,
- Carbonation: When rainwater falls on limestone rocks, the calcium carbonates present in the rocks absorb carbon dioxide from rainwater and become calcium bicarbonate.
- Hydration: Hydration is a process by which some minerals in crystalline form absorb water and become powdery mass. Feldspar is a common rock-forming crystalline mineral.
- Solution: When rainwater falls on the surface of the earth it dissolves soluble minerals present in the rocks.
Question 51.
How does biological weathering take place?
Answer:
Living organisms like plants, animals and human beings play a role in one way or the other in weathering the rocks. This includes both physical and chemical weathering. Plants, through their growth and expansion, cause weathering. Animals, particularly through burrowing, and human beings through mining, quarrying and construction work cause weathering.
Question 52.
What is denudation? Which are the agents of denudation?
Answer:
Denudation is the action of changing the landscape or changing the surface of the earth by various natural agents such as rivers, glaciers, underground water, wind, sea waves, etc. The works, of these agents are erosion, transportation and deposition. These processes produce distinct relief features.
Question 53.
What is a river? Name the different stages of its course.
Answer:
A mass of fresh water flowing from its source to mouth along a definite course is called a ‘river’. The place where the river takes its birth is called the ‘source’ and the ‘mouth’ is the point where it meets the sea or ocean. Tributaries are the small streams or feeders which supply water to the river along its course.
The point where a tributary meets a river is called confluence. The course of a river from its source to mouth is divided into three stages. These are upper course, middle course and lower course.
Question 54.
Write a note on upper course of the river. What land forms are formed in this stage?
Answer:
Vertical erosion is most common in the upper course due to steep slopes leading to deepening of valleys, resulting in the formation of gorges, canyons, V-shaped valleys and waterfalls.
Question 55.
Write a note on middle course of the river. What land forms are formed in this stage?
Answer:
In the middle course the river path has a moderate slope and velocity is less than that in the upper course. Here, the volume of water increases when many tributaries join the main river. The main work of the river in this stage is transportation of sediments and little deposition. The important land forms in this stage are alluvial fans and meanders.
Question 56.
Write a note on lower course of the river. What land forms are formed by the river in its lower course?
Answer:
In the lower course of the river the slope of the river course is minimum. The volume of water is more and deposition is the main work of the river. The important land forms in this course are flood plains, natural levees, ox-bow lakes and deltas.
Question 57.
Distinguish between delta and estuary.
Answer:
Delta is a fan-shaped low lying area of deposits at a river mouth. Estuary is the tidal mouth of a river broadening into the sea or ocean.
Question 58.
What are glaciers? How are they formed?
Answer:
Glaciers are slow-moving, compact masses of ice and snow found in high mountains and polar regions. Glaciers are formed when the mass of snow or ice is pulled down by its weight and force of gravity.
Question 59.
Which are the different types of glaciers? Explain.
Answer:
Glaciers are divided into two types – continental glaciers and mountain glaciers. Continental glaciers: Continental glaciers are continuous and extensive ice sheets found only in Polar regions. They cover parts of continental land masses. eg: Greenland and Antarctica. Mountain or Alpine or valley glaciers: Mountain glaciers are found only at high altitudes such as mountain tops and they move downward through valleys.
Question 60.
Name the landforms associated with the work of rivers.
OR
Name the different landforms formed by rivers as agents of denudation.
Answer:
As agents of denudation, rivers form Landforms like gorges, V-shaped valleys, waterfalls, alluvial fans, meanders, flood plains, natural levees, ox-bow lakes, deltas, etc.
Question 61.
Which are the Landforms created by glaciers?
Answer:
The Landforms created by glaciers are cirque, horn, arete, U-shaped valleys, hanging valleys, rock steps, moraines, drumlins, esker, kames, outwash fans, till plains, etc.
Question 62.
What are moraines? Which are the different types of moraines?
Answer:
Moraines are landforms produced by the depositional work of glaciers. They are the most important landforms of the glaciated region. They are of four types – lateral moraines, medial moraines, ground moraines and terminal moraines.
Question 63.
Write a note on the different types of moraines.
Answer:
Moraines are of four types – lateral moraines, medial moraines, ground moraines and terminal moraines.
- Lateral moraines: They are rock debris deposited along the sides of the glacial valley.
- Medial moraines: They are formed when two lateral moraines meet.
- Ground moraines: They are rock materials found on the floor or at the bottom of the glacial valley.
- Terminal moraines: They are the glacial deposits found at the end of the glacier.
Question 64.
What is glacial cycle?
Answer:
The transportation and the deposition work of glaciers go almost together. This work of a glacier is called glacial cycle.
Question 65.
What is underground water?
Answer:
Underground water is the subsoil water found on account of percolation or seepage of water into the ground.
Question 66.
What are water springs? How are they formed?
OR
Distinguish between porous rocks and non-porous rocks.
Answer:
A water spring is a place where underground water comes out naturally. The underground water which seeps into the ground, passes through various layers of rocks. The rocks which allow the water to percolate are called pervious or porous rocks and the rocks which do not allow water inside are called impervious or non-porous rocks.
The porous rock beds which hold large amount of underground water are called aquifers. The porous rocks allow and hold water and form springs.
Question 67.
What are aquifers?
Answer:
The porous rock beds which hold large amount of underground water are called aquifers.
Question 68.
Which are the different types of water springs? Explain.
Answer:
Water springs are of different types. They are:
- Perennial spring: It is a spring through which water comes out continuously.
- Intermittent springs: These are springs through which water comes out intermittently. These are also called periodic springs.
- Hot springs: Whenever warm or hot water comes out naturally, it is called hot spring or thermal spring. They are normally found near the volcanic regions.
- Geyser: These are springs which throw a jet of hot water and steam into the air at regular or irregular intervals.
- Artesian wells: When underground water is stored in a basin-shaped layer between two non-porous rocks, the water cannot come out naturally. If an artificial hole is made to the porous rock the water comes out like a fountain. These are called artesian wells.
Question 69.
What are artesian wells? Where are they generally found?
Answer:
When underground water is stored in a basin-shaped layer between two non-porous rocks, the water cannot come out naturally. If an artificial hole is made in the porous rock the water comes out like a fountain. These are called artesian wells. They are commonly found in Australia.
Question 70.
Which are the landforms formed by underground water?
Answer:
The important landforms formed by underground water are Lapies, sinkholes, limestone caves, stalactites, stalagmites, calcite pillar, etc.
Question 71.
Where are limestone caves found in India?
Answer:
Akalagavi (Ulavi) caves of Uttara Kannada in Karnataka and Belum and Bohra caves of Andhra Pradesh are the limestone caves found in India.
Question 72.
Name the landforms associated with the work of wind.
Answer:
Denudation work of wind is common in arid or desert regions. When winds of high velocity blow over desert areas they erode, transport and deposit materials to form different landforms. Landforms associated with depositional work of wind are rock pedestals, mushroom rock and inselberg. Depositional landforms are sand dunes – longitudinal sand dunes, barchans and loess deposits.
Question 73.
Where are barchans and loess deposits found?
Answer:
Barchans are semi-circular or crescent shaped sand deposits commonly found in deserts. Loess deposits are sand particles found beyond the borders of deserts, as for example, Yellow soil in China.
Question 74.
What is Aeolian cycle?
Answer:
The work of wind is called Aeolian cycle.
Question 75.
Which are the land forms formed by the sea waves?
Answer:
The important land forms associated with sea waves are Cliff, Sea cave, Sea stack, Sea arch, Headland, Sandbars, Beaches, Lagoons, etc.
Question 76.
Define the following:
Answer:
- Aqueous rocks: Sedimentary rocks are formed in water bodies like lake, sea or ocean. Hence they are called aqueous rocks.
- Pacific ring of fire: Coastal margins of the Pacific Ocean consisting of Philippines, Japan, USA, Central America, South America, etc., form a kind of ring. These areas around the Pacific have many volcanically active regions. Hence, this region is called Pacific Ring of Fire.
- Mechanical weathering: Mechanical or physical weathering is the process of breaking down and disintegration of rocks without any chemical alteration.
- Carbonaceous rocks: Carbonaceous rocks are a type of organic sedimentary rocks that are derived by the accumulation of remains of organisms such as shells of marine organisms and remains of plants and animals.
- Tsunami: Tsunami is a large sea wave caused by an underwater earthquake.
- Continental glacier: Continental glaciers are extensive ice sheets.found in Polar regions.
- Hot spring: A hot spring or thermal spring is a spring produced by the emergence of geothermally heated oundwater that rises naturally from the Earth’s crust.
Multiple Choice Questions
Question 1.
The outermost solid layer of the earth is known as
(A) Lithosphere
(B) Hydrosphere
(C) Atmosphere
(D) Stratosphere.
Answer:
(A) Lithosphere
Question 2.
The upper part of the earth’s crust is called SIAL because
(A) it is rich in sodium and aluminium
(B) it is rich in silica and aluminium
(C) it is rich in magnesium iron
(D) it is rich in sulphur and phosphorus.
Answer:
(B) it is rich in silica and aluminium
Question 3.
The lower part of the crust known as ‘Oceanic Crust’ is rich in
(A) aluminium and copper
(B) magnesium and aluminium
(C) copper and gold
(D) silica and magnesium.
Answer:
(D) silica and magnesium.
Question 4.
The middle layer of the earth’s interior is called
(A) mantle
(B) core
(C) crust
(D) magma.
Answer:
(A) mantle
Question 5.
The innermost layer of the earth’s interior core is also called
(A) SIAL
(B) SIMA
(C) NIFE
(D) FESI.
Answer:
(C) NIFE
Question 6.
Which is the right sequence of the different layers of the earth’s interior?
(A) SIAL, SIMA, Asthenosphere, Mesosphere, NIFE
(B) SIMA, SIAL, Asthenosphere, NIFE, Mesosphere
(C) Asthenosphere, Mesosphere, SIAL, SIMA, NIFE .
(D) NIFE, SIAL, SIMA, Asthenosphere, Mesosphere.
Answer:
(A) SIAL, SIMA, Asthenosphere, Mesosphere, NIFE
Question 7.
Which of the following are called ‘Primary rocks’?
(A) Metamorphic rocks
(B) Sedimentary rocks
(C) Igneous rocks
(D) Stratified rocks.
Answer:
(C) Igneous rocks
Question 8.
The igneous and sedimentary rocks get transformed into metamorphic rocks due to
(A) chemical action
(B) heat and pressure
(C) erosion
(D) dissolution of soluble material.
Answer:
(B) heat and pressure
Question 9.
Precious stones like sapphire, ruby, emerald and diamonds are found in ________ rocks.
(A) sedimentary rocks
(B) metamorphic rocks
(C) igneous rocks
(D) aqueous rocks.
Answer:
(B) metamorphic rocks
Question 10.
The funnel-shaped hollow at the top of the cone of a volcano is called
(A) Crater
(B) Caldera
(C) Vent
(D) Magma.
Answer:
(A) Crater
Question 11.
Which one of the following flows out from a volcano?
(A) Magma
(B) Lava
(C) Igneous rocks
(D) all of these.
Answer:
(B) Lava
Question 12.
Which one of the following is an active volcano?
(A) Mt. Krakatoa of Indonesia
(B) Mt. Vesuvius of Italy
(C) Mt. Fujiyama of Japan
(D) Mt. Stromboli and Mt. Etna in Italy.
Answer:
(D) Mt. Stromboli and Mt. Etna in Italy.
Question 13.
Which waves caused by earthquakes cause maximum damage and destruction on earth’s surface?
(A) Primary waves
(B) Push waves
(C) Distortional waves
(D) Long waves.
Answer:
(D) Long waves.
Question 14.
Undersea earthquakes can cause
(A) tsunami
(B) volcanoes
(C) landslides
(D) hot springs.
Answer:
(A) tsunami
Question 15.
Wearing away or breaking down or gradual disintegration of rocks by agents is called
(A) weathering
(B) denudation
(G) deposition
(D) transportation.
Answer:
(A) weathering
Question 16.
Rivers, glaciers, underground water, winds and waves are
(A) agents of weathering
(B) agents of denudation
(C) internal forces
(D) agents of deposition.
Answer:
(B) agents of denudation
Question 17.
Which of the following landforms is formed in the upper course of the river?
(A) Estuary
(B) Delta
(C) Alluvial fans
(D) Waterfalls.
Answer:
(D) Waterfalls.
Question 18.
‘U’ shaped valleys are caused by the denudation work of
(A) rivers
(B) rainwater
(C) sea waves
(D) glaciers
Answer:
(D) glaciers
Question 19.
The important depositional landform produced by glaciers is
(A) flood plains
(B) moraines
(C) barchans
(D) Iselberg
Answer:
(B) moraines
Question 20.
The underground water coming out naturally is called
(A) river
(B) artesian well
(C) spring
(D) lapies
Answer:
(C) spring
Question 21.
Which one of the following land forms is caused by winds?
(A) Sinkholes
(B) Mushroom rock
(C) Lapies
(D) Headland
Answer:
(B) Mushroom rock
Question 22.
Which agent of denudation causes ‘Loess’?
(A) Underground water
(B) Sea waves
(C) Winds
(D) Glaciers.
Answer:
(C) Winds
Question 23.
Stalactites and stalagmites are formed by the work of
(A) surface water
(B) sea waves
(C) underground water
(D) winds.
Answer:
(C) underground water
Fill up In The blanks
- The continental crust is also called SIAL.
- Vast basin-shaped volcanic mouth is Caldera.
- The most destructive earthquake waves are long waves.
- Stalactites and stalagmites are most common in limestone areas.
- Beaches are formed by the work of sea waves.
- The upper layer of the crust is called SIAL because it is rich in silica and aluminium.
- The lower layer of the earth’s crust is called SIAM/oceanic crust.
- The Layer of the earth lying in between the earths crust and the core is mantle.
- The partially molten upper layer of the mantle is asthenosphere.
- The contact zone of the crust and the mantle is called mohorovicic Discontinuity /moho.
- The boundary that separates the mantle from the core is called Gutenberg Discontinuity.
- The core is called NIFE because it is rich in Nickel and Ferrous (iron)
- Igneous rocks are also called primary rocks.
- The rock material in liquid or molten state in the interior of the earth is called magma
- Sedimentary rocks are also called aqueous rocks because they are formed in water bodies like seas and oceans.
- Mt. Fujiyama and Mt. Vesuvius are dormant volcanoes.
- The liquid that flows out of a volcano is called lava
- The origin, time, velocity and direction of seismic waves are recorded by an instrument known as Seismograph.
- The dangerously huge waves caused when earthquakes take place under the ocean bed are called tsunami
- In India, the Himalayan region is highly earthquake-prone.
- Changing of the surface of the earth by various natural agents is called denudation.
- The fan-shaped, low lying areas of deposits at the mouth of the river are called deltas.
- The compact mass of ice and snow moving slowly is called glacier.
- Moraines are formed due to the denudation work of glaciers.
- The artesian wells are commonly found in Australia.
- The semi-circular, crescent shaped sand deposits most common in the deserts are caused by winds.
Match The following
Question 1.
A | B |
a. SIMA | 1. Earthquake |
b. Sandstone | 2. Yellow soil. |
c. Epicentre | 3. Oceanic crust |
d. Geyser | 4. Sedimentary rock |
e. Loess | 5. Underground water |
Answer:
a – 3, b – 4, c – 1, d – 5, e – 2.
Question 2.
A | B |
a. Mantle | 1. Boundary between mantle and core |
b. Magma | 2. Middle layer of the earth’s interior |
c. Asthenosphere | 3. Liquid rock material |
d. Mesosphere | 4. Upper layer of the mantle |
e. Moho | 5. The region where mantle and crust meet |
6. Lower layer of the mantle |
Answer:
a – 2, b – 3, c – 4, d – 6, e – 1.
Question 3.
A | B |
a. Instructive igneous rock | 1. Basalt |
b. Extrusive igneous rock | 2. Rock salt |
c. Carbonaceous rock | 3. Marble |
d. Chemically formed sedimentary rock | 4. Lava |
e. Metamorphic rock | 5. Granite |
6. Coal |
Answer:
a – 5, b – 1, c – 6, d – 2, e – 3.
Questions 4.
A | B |
a. Upper course of the river | 1. Moraines |
b. Lower course of the river | 2. Springs |
c. Glacier | 3. Crescent shaped sand deposits |
d. Winds | 4. Delta |
E. Sea waves | 5. V-shaped valley |
6. Land head |
Answer:
a – 5, b – 4, c – 1, d – 3, e – 6.