Karnataka 1st PUC Geography Question Bank Chapter 3 Interior of the Earth Questions and Answers Solution, Notes by Expert Teacher Priya Verma. Karnataka Class 11 Geography Solution Chapter 3.
There are 2 Parts in Karnataka Class 11 Textbook. Here You will find Part A Fundamentals of Physical Geography’s Chapter 3 Interior of the Earth (Structure and Composition of the Earth, Earthquakes, Volcanoes, Rocks and Minerals).
Karnataka 1st PUC Geography Question Bank Chapter 3 – Interior of the Earth Solution
- State – Karnataka.
- Class – 1st PUC / Class 11
- Subject – Geography.
- Topic – Solution / Notes.
- Chapter – 3
- Chapter Name – Interior of the Earth.
- Subpart – Structure and Composition of the Earth, Earthquakes, Volcanoes, Rocks and Minerals.
(I) Answer the following in a word or a sentence each.
(1) What is Continental Crust?
Answer :
Continental crust is uppermost layer of crust found in continents. It is thicker than the oceanic crust.
(2) Name the discontinuity found between Mantle and Core.
Answer :
Discontinuity between mantel and core is called as Mohoroviviv or Moho discontinuity.
(3) Why is the inner core called ‘Solid Core’?
Answer :
Inner core is called as solid core because most of the material found in this layer are in solid state. It has high density, and it is usually made up of nife layer.
(4) Name the instrument used to record seismic waves.
Answer :
Instrument used to record seismic waves is Seismograph.
(5) Which is the most destructive earthquake wave?
Answer :
The most destructive earthquake waves are Surface waves.
(6) Define Tsunami.
Answer :
Tsunami is a large destructive sea wave which is experienced across the coastal areas.
(7) What is Homo-seismal line?
Answer :
Homo-seismal lines are The lines on map which show the places which experience the occurrence of earthquakes at same time.
(8) Mention the region which record more seismic activities in the world.
Answer :
Most seismic activities are observed in the world in the Circum-Pacific belt.
(9) What is Volcano?
Answer :
Volcano is a natural hazard in which the molten lava and magma erupts out of the crust.
(10) Name any one volcano of India.
Answer :
The only volcano of India is in Barren Island.
(11) Which is a famous active Volcano in USA?
Answer :
Famous volcano of USA is St Helens.
(12) What is ‘Ring of Fire’?
Answer :
Ring of fire is continuous chain of mountains in the Circum-pacific belt region which show continuous volcanicity.
(13) Define Petrology.
Answer :
Petrology is the scientific study of rocks.
(14) Give an example for Plutonic rock.
Answer :
Examples of Plutonic rocks are Granite, Gabbro, Diorite etc.
(15) Why are secondary rocks called Aqueous rocks?
Answer :
Secondary rocks are also called as aqueous rocks because they are formed by the deposition of sediments by the action of wind and water.
(16) How is Carbonaceous rock formed?
Answer :
Carbonaceous rocks are formed by decay and decomposition of the living matter.
(17) What is Metamorphism?
Answer :
Metamorphism is a process in which rocks undergoes transformation under high temperature and pressure conditions. It makes rocks harder and rich in mineral content.
(18) What is a Mineral?
Answer :
Minerals are inorganic natural substances which are of great economic importance.
(19) Which mineral covers largest area of the Earth’s crust?
Answer :
The mineral which covers the largest area of earth is Feldspar.
(20. Give an example for non-ferrous mineral.
Answer :
Examples of non-ferrous minerals are bauxite, mica etc.
(II) Answer the following in two or three sentences each.
(1) Mention any two features of Oceanic Crust.
Answer :
Oceanic crust is found in the bottom of the oceans. It is comparatively thinner than the continental crust. The two main features of oceanic crust are- It has a mean density of 2.95 g/cm3 and it is made up of silica and magnesium.
(2) Why is Mantle very important in the Earth’s interior?
Answer :
Mantel is an important layer in earth’s interior because it is a semi liquid or molten layer with high temperature which aids in the tectonic movements of the plates in earth’s crust.
(3) State the difference between Focus and Epicentre.
Answer :
Focus is the point inside the earth’s crust from where the earthquake originates whereas the epicentre is the point on the earth’s crust directly above the focus. It is the point on the earth’s crust which is at least distance from the focus.
(4) Name any two causes for earthquakes.
Answer :
Earthquakes are cause by the natural causes like tectonic folding and faulting, or because of the volcanic eruptions. It can also be caused by the man-made cause like construction of large dams, nuclear explosion etc.
(5) Distinguish between Iso-seismal and Co-seismal lines.
Answer :
Iso-seismal lines are the lines on the map which show the places which experience earthquakes of same intensity whereas, co-seismal lines are the ones which show the places which experience earthquakes of same intensity as well as same time of occurrence.
(6) Which scales are used to measure the intensity of an earthquake?
Answer :
Intensity of earthquakes are measure by the Richter and Mercalli scale. Richter scale measures the magnitude of the earthquake and Mercalli scale measures its intensity.
(7) Mention any two causes of a Volcano.
Answer :
Volcanic eruptions are caused by various reasons like- Formation of magma with the increase in temperature and decrease in pressure, increase of temperature with the increasing depth, formation of gases and water vapours inside the earth etc.
(8) Distinguish between Active and Extinct volcanoes.
Answer :
Active volcano are the ones which have erupted in the recent past and show a continuous eruption of magma and lava. For example, Mt. Etna and Mt. Stromboli in Italy, St Helens of USA etc.Whereas extinct volcanoes are the ones which have erupted in the geological past but has not shown any activity in the recent past.For example, Narcondam in Andaman and Nicobar, Mt Aconcagua in Argentina etc.
(9) Name any two active volcanoes of the World.
Answer :
Mt Etna and Mt Stromboli of Italy, St Helens of USA, Mauna Loa and Mauna Kea of Hawaiian Islands etc are the active volcanoes in the world.
(10) Name any two countries which come under the Circum- Pacific belt.
Answer :
Circum-Pacific belt is the area of active volcanicity and is also known as Ring of Fire. Countries like Japan, New Zealand, New Guinea, South America, Western part of Alaska and USA, Hawaii islands fall in this region.
(11) How are Igneous rock formed? Give examples.
Answer :
Igneous rocks are formed by the cooling of molten rock material or magma. They are usually formed by the volcanic action. There are two types of Igneous rocks- Intrusive igneous rocks and extrusive igneous rocks. For example, Granite, Gabbro, Basalt etc.
(12) Distinguish between Arenaceous and Argillaceous rocks.
Answer :
Arenaceous rocks are the sedimentary rocks formed by the sand grains and they are porous in nature. For example, sandstone. While Argillaceous rocks are sedimentary rocks which are made up of fine clay particles and are non-porous in nature. For example, Shale.
(13) How is contact metamorphism different from regional metamorphism?
Answer :
Contact metamorphism is the process of metamorphism which occurs when the hot molten lava comes in contact with the joints and fissures of the rocks. It is also known as thermal or local metamorphism. For example, the formation of marble from the limestone. Regional metamorphism happens when the igneous or sedimentary rocks are buried deep inside the earth and undergo metamorphosis because of high pressure and temperature. For example, Slate from clay, Graphite from coal etc.
(14) Give four examples of Metamorphic rock.
Answer :
Examples of metamorphic rocks are gneiss, schist, quartzite, slate, marble, graphite etc.
(15) What are metallic and non-metallic minerals?
Answer :
Metallic minerals are composed of one or more metals. For example, iron ore, manganese ore, bauxite etc. While non metallic minerals do not contain any metal element. For example, phosphate, asbestos, mica etc.
III Answer the following.
(1) Explain the structure and composition of the Earth with a neat diagram.
Answer :
Earth is a geoid which is flattened on poles and bulges out near equator. The internal structure of the earth is being gauged by the velocity of seismic waves, density of material, chemical composition etc. The earth’s interior is divided into three parts-
- TheCrust– It is the uppermost layer of earth, and it is divided into two types on the basis of its location and composition. They are continental crust and oceanic crust. Continental crust has a thickness of about 30-60 km and is made up of Silicon and aluminium. Whereas oceanic crust has a thickness of about 5 km and is made up of silicon and magnesium.
- Themantle– Mantle is the middle layer of earth. It contains molten rocks material. It extends from 60 km to 2,900 km. It is present in partially molten state and is composed of dense rigid rocks like magnesium and iron. Upper mantle is known as asthenosphere which is in molten condition. And the lower mantle is in the solid state and is known as Mesosphere.
- Thecore– The core is the innermost layer of earth. It has very high temperature and pressure. It is composed of nickel and iron and is known as nife layer. Outer core is made up of hard molten rocks whereas inner core is made up of solid rocks. Core has a density of about 5.5 to 11 gm/cm3.
(2) What is an Earthquake? Describe the causes and effects of earthquake.
Answer :
Earthquake is a natural disaster which is caused by the sudden movement of the tectonic plates in the interior of the earth. It is caused by the sudden release of energy. The point inside the earth’s crust from where the energy has been released is known as focus and the point just above it on the earth’s crust is known as epicentre. The scientific study of earthquakes is known as seismology.
Causes of earthquakes-
- Tectonicmovements– It is caused by the folding, faulting, and displacement of rocks on the earth’s crust.
- Volcanicearthquakes– These earthquakes are cause by the volcanic eruption.
- Manmadecauses– Earthquakes caused because of man made reasons like nuclear explosions, reservoirs, deep mining etc.
Earthquakes are considered as a natural disaster. They are measured using Richter Scale and Mercalli Scale. The destruction caused by the earthquakes depends upon the strength of the seismic waves generated. Earthquakes damage, topography, course of river, structure of mountains, underground water etc and cause huge loss to land, life and property.
(3) How does a Volcano erupt? Explain the types of Volcanoes.
Answer :
Volcano is a natural disaster which causes great damage to land, life and property. Volcano is a vent opening on the earth’s crust from which molten matter, rocks, gases, hot water, lava etc is ejected. The passage from which the magma erupts out is known as vent. The funnel shaped opening on the top of the volcano is known as Crater and the large lava source beneath it is known as caldera. There are various causes of volcanic eruption-
- Increase in temperature inside the earth.
- Formation of magma inside the earth at high temperature and pressure.
- Gases and water vapours formed inside the earth because of high temperature.
- Movement of tectonic plates and their folding and faulting.
- Upward movement of magma because of high pressure.
There are three types of volcanoes-
Active volcano- Volcanoes which have erupted in recent past and show an active sight of volcanicity by ejecting solids and gaseous materials are known as active volcanoes. For example, Mt Etna, Mt Stromboli, St Helens etc
Dormant Volcano- Volcanoes which have erupted in recent past and do not show any signs of present volcanicity are known as dormant volcanoes. For example, Mt Vesuvius, Mt Fujiyama, Mt Krakatau etc.
Extinct Volcano- The volcanoes which have erupted in geological past but have no signs of volcanism in recent past are known as extinct volcanoes. For example, Narcondum, Aconcagua etc.
(4) What is a rock? Describe the different types of rocks.
Answer :
Rocks are the solid structures found in earth’s crust. These are formed by the aggregation of minerals. The scientific study of rocks is known as Petrology. Lithosphere is the upper most layer of the earth which is formed by rocks. There are three types of rocks-
- Igneous rocks– The rocks of volcanic origin are known as igneous rocks. They are formed in contact with lava. There are two types of igneous rocks- Intrusive igneous rocks which are formed inside the earth’s crust and the extrusive igneous rocks which are formed by the solidification of lava on the surface of earth’s crust. For example, Granite, Basalt, Gabbro etc.
- Sedimentary rocks– The rocks which are formed by the accumulation and consolidation of sediments by the action of wind and water are known as sedimentary rocks. For example, sandstone, limestone etc.
- Metamorphic rocks– The rocks which are formed by the metamorphosis of the igneous and sedimentary rocks by the action of the increased temperature and pressure are known as metamorphic rocks. For example, Schist, Slate, marble etc.
(5) What is a mineral? Explain the types of minerals.
Answer :
Minerals are inorganic substances which have distinct physical and chemical properties. The scientific study of minerals is known as mineralogy. For example, Feldspar, quartz, bauxite etc. Based on nature and texture minerals are classified into two categories. Metallic minerals are composed of one or more metals. For example, iron ore, manganese ore, bauxite etc. While non-metallic minerals do not contain any metal element. For example, phosphate, asbestos, mica etc. Minerals are also of two types- ferrous minerals and non-ferrous minerals. Ferrous minerals are iron containing minerals like iron ore and non-ferrous minerals are non-iron containing minerals like bauxite, mica etc.