Samacheer Kalvi 9th Social Science Geography Solutions Chapter 1 Pdf

Samacheer Kalvi 9th Social Science Geography Solutions Chapter 1 Pdf

Tamilnadu Board Samacheer Kalvi 9th Social Science Geography Solutions Chapter 1: Tamilnadu State Board Solution Class 9 Social Science Geography Chapter 1 – Lithosphere – I Endogenetic Processes.

Samacheer Kalvi 9th Social Science Geography Solutions Chapter 1: Overview

Board

Samacheer Kalvi
Class

9

Subject

Social Science (Geography)
Chapter

1

Chapter Name

Lithosphere – I Endogenetic Processes


Samacheer Kalvi 9th Social Science Geography Solutions Chapter 1 Lithosphere – I Endogenetic Processes

I.) Choose the correct answer

1.) Crust is the rigid outer layer of theEarth.

a.) core

b.) mantle

c.) Crust

d.) inner core

2.) Outer core layer is made up ofliquid iron

a.) Inner core

b.) Outer core

c.) Mantle

d.) Crust

3.) Magma is found in the mantle.

a.) crust

b.) mantle

c.) core

d.) None of the above

4.) The movement of tectonic plates isinduced by thermalenergy.

a.) hydel

b.) thermal

c.) wave

d.) tidal

5.) In the ancient period,Gondwanaland moved towardsnorthdirection.

a.) north

b.) south

c.) east

d.) west

6.) Many million years ago, India was apart of the super continentGondwana.

a.) Gondwana

b.) Laurasia

c.) Panthalasa

d.) Pangea.

7.) The movement of plates that createsstress and tension in the rocks causingthem to stretch and cracks resultinfault.

a.) fold

b.) fault

c.) mountain

d.) earthquake

8.) Crater refers to a bowl-shaped depressionfound at the top of the volcano.

a.) crater

b.) vent

c.) chamber

d.) volcanic cone

9.) The point of origin of an Earthquake is calledthe focus.

a.) epicentre

b.) focus

c.) seismic wave

d.) magnitude

II.) Match the following

Answer

1.) Endogeneticprocess                                                           — Volcanic

2.) Mantle                                                                                — SIMA

3.) Convergentboundaries                                                       — Subduction Zone

4.) Earthquake                                                                         — Seismograph

5.) Compositevolcano                                                             — Pacific Ocean

III.) Consider the given statements

1.) i. Mt. Fuji is a dormant volcano.

ii.) Mt. Kilimanjaro is a dormantvolcano.

iii) Mt. Tanzania is a dormant volcano.

Which of the statement(s) is/are true?

a.) i is true

b.) ii is true

c.) iii is true

d.) i, ii, iii are true

Answer: Statement i is true.

2.) Statement: Magma gushes out when itfinds vents.

Reason: Interior of the Earth containscompressed hot magma

a.) Statement & reason are true

b.) Statement is true, reason is false

c.) Statement is false reason is true

d.) Statement & reason are false

Answer:a. Statement & reason are true

3.) Statement I: Mountain ranges are formedby the collision of tectonic plates

Statement II: The movement oftectonic plates is due to the thermalenergy from the mantle

a.) Statement I is false II is true

b.) Statement I and II are false

c.) Statement I is true II is false

d.) Statement I and II are true

Answer:d. Statement I and II are true

IV.) Answer in brief:

1.) Write a brief note on the various spheresof the Earth.

Answer: The Earth is very big; it is around 510 million sq.km. The Earth divided into four spheres. Lithosphere, atmosphere and hydrosphere are abiotic spheres and biosphere considered as biotic sphere.

2.) Mention the layers of the interior of theEarth.

Answer: The nature of inner core and the outer surface is different and their structure is also different. The interior of the Earth divided into three layers and those layers are the crust, the mantle and the core.

3.) Define Plate tectonics.

Answer: There are many big slabs of rocks known as ‘Tectonic plates.’ Tectonic plates having two types: major tectonic plates and minor tectonic plates. These plates are floating over the mantle and when these floating plates hit each other then collisions takes place and as a result mountain ranges and other irregular surface features came into existence on the land and as well as in ocean floor. This natural process is known as ‘Plate tectonics’.

4.) What is Tsunami?

Answer: ‘Tsunami’ is the Japanese word for harbour waves. The word ‘Tsunami’ is used to describe big sea waves generated by seismic movement. Seismic movement can happen due to Earthquakes, submarine explosions and landslides. Tsunami waves have great speed, which more than 500 km per hour and the length of the waves is more than 600 km per hour. The height of this kind of wave could be 15 meters when close to sea shore. Tsunami waves could be very destructive for the coast.

5.) What is a Volcano? Mention its major components.

Answer: A volcano is breakout point on the surface of the Earth crust. Hot solid, liquid and gaseous materials known as Magma came out through volcano. When magma came out of volcano, on the surface of the earth it known as Lava. There are four types of major components of volcano.

i) Magma Chamber: Magma chamber is a big area where rock are found in a liquid form, it is under the earth.

ii) Vent: Vent is a point from where air, fumes, magma, smoke etc. comes out from the beneath of the earth to on the surface of the earth.

iii) Volcanic cone: When the magma ejected through the earth and came out on the surface of the earth it gets harden when it comes in the contact of the environment of the earth and the shape of cone is known as volcanic cone.

iv) Crater: At the top of the volcano a bowl-shaped depression takes place through which the magma flows out is known as Crater.

6.) What is an Earthquake and how it occurs?

Answer:The vibrations from the crust of the Earth spreads to all directions as a wave suddenly and create disturbance then Earthquake happens. Origin point of the earthquake is known as ‘Focus’ also known as Hypocentre. This focus starts a series of elastic waves. Above the focus ‘Epicentre’ is found. The strong impact of the earthquake can be felt on the epicentre.

7.) What are seismic waves and mention itstypes?

Answer: When the earthquake happens, seismic waves are emitted. The medium through which seismic waves are passing determines the nature, force and speed of it. Seismic waves are have three types

i) Primary seismic waves or P-waves

ii) Secondary seismic waves or S-waves

iii) Surface seismic waves or L-waves

8.) Write about the Pacific Ring of fire.

Answer: Pacific Ring of Fire is the place surrounded with the other plates and Pacific plates comes into contact with other plates. This area is known as the most seismically active and volcanos in this area are active hence this place is famous for worldwide.

V.) Give Reasons for the following:

1.) Igneous rocks are also called Primary Rocks or Mother rocks.

Answer: The reason behind calling Igneous rocks as Primary Rock or Mother Rock is the process of formation. Igneous rock is formed from the Magma which comes out from inside of the earth. Magma turns into Lava when it reaches on the surface of the earth. When Lava cools down and turns into solid it turns into igneous rocks and this is primary stage of rock. All other rocks either directly or indirectly formed from this rocks hence the Igneous rock is called Primary rock or Mother rock.

VI.) Distinguish between

1.) Core and crust.

Answer:

Core Crust
Core is the innermost layer of the earth Crust is outer layer of the earth
The major elements of the core are Nickel (Ni) and Iron (Fe). The major elements of the crust are SIAL means Silica (Si) and Aluminium (Al) and SIMA means Silica (Si) and Magnesium (Ma).
Core is lies below the mantle. Crust is ranges between 5 to 30 km from the surface of the earth.

2.) Epicentre and Hypocentre

Answer:

Epicentre Hypocentre
Epicentre is the point above the focus i.e. Hypocentre on the surface of the earth. Hypocenre is the origin point of the Earthquake.
Epicentre generates vibrations or waves inside of the earth. Hypocenre generates series of elastic waves.
Impact of the earth felt the most at the epicentre. It is the origin point of the earthquake and generates elastic waves.

3.) Divergent and convergent boundaries.

Answer:

Divergent Boundaries Convergent Boundaries
In Divergent boundaries, plates pull away from each other as magma pushes up from the mantle. In Convergent boundary plates moves toward each other and sometimes a plate sink under another.
Divergent boundaries are plates going away from each other creates boundaries. The location where plate sink called subduction zone and creates Convergent boundaries.
Divergent Boundaries forms floor for the lake or oceans. Convergent Boundaries moves towards each other and forms mountains.

4.) Primary waves and Secondary waves.

Answer:

Primary waves Secondary waves
Primary waves are the fastest of all the earthquake waves. Secondary waves are not fast as primary waves.
Primary waves can pass through solids, liquids and gases. Secondary waves pass through solids only.
The average velocity or primary wave is 5.3km per second to 10.6km per second. The average velocity of secondary wave is 1km per second to 8km per second.

5.) Shield volcano and volcanic Dome.

Answer:

Shield Volcano Volcanic Dome
Shield volcano is formed by intense viscous lava. Volcanic dome is formed by slow ejection of viscous lava.
Shallow depositions of lava create sloping sides from all sides. Intense viscosity of lava prevents it from flowing away and it creates a dome.

VII.) Write answers in a Paragraph

1.) Describe the structure of the Earth.

Answer: The structure of the earth divided into three layers the crust, the mantle and the core. Let’s talk about these three layers

i) The Crust: The crust is the outmost layer of the earth. It is like the skin of the earth. The range of the crust it from 5 km to 30 km from the surface of the earth. The thickness of the crust is more in the below the continents as compared to oceanic floor. There are two types of crust Continental crust and oceanic crust. SIAL and SIMA are the elements of the crust. SIAL means Silica and Aluminium and SIMA means Silica and Magnesium.

ii) The Mantle: This part of the earth is below crust and known as mantle. This mantle is 2900 km thick. The rocks and remained solid part reside at upper part of mantle and in the lower part of the mantle molten rocks are found, these molten rocks are known as magma.

iii) The Core: The core is the core area of the earth; it is the innermost part of the earth hence it is the hottest layer. This core is composed with Nickel and Iron, also known as NIFE. The core has two parts Solid inner core and liquid outer core. The iron residing in a large quantity is responsible for the gravitational force of the earth. The liquid outer core spins on the solid inner core and generates magnetic field. The inner core remains solid due to the high pressure.

2.) Write a note on the internal and external processes of Earth.

Answer: i) Internal Processes: The internal processes is also known as Endogenetic processes. This process generates heat and eject material from the deep crust. The principal source of power for this process is internal radioactivity.

ii) External processes: External processes can be seen on the surface of the Earth. This process takes place due to natural agents like running water, glacier, wind, waves etc. The external process changes the surface for example relatively low elevated plains and changed shape of landform are the results of external process. External process is also known as Exogenetic processes.

3.) How are volcanoes classified based onthe periodicity of their eruptions?

Answer: Volcanos are the vent for the magma on the earth. These volcanos are classified based on the periodicity of eruptions. There are three classifications of volcano: Active Volcano, Dormant Volcano and Extinct volcano.

i) Active Volcano: The volcanos continuously ejecting lava and gases and other materials are known as Active Volcanos. E.g. Mt. St. Helens in US.

ii) Dormant Volcano: Dormant volcanos doesn’t show any activity for long period of time are known as Dormant Volcano. But there is always scope of explosion and it could be loss of lives and property if we neglected it and didn’t took any precaution while visiting such volcanos. Dormant Volcanos also known as Sleeping Volcanos. Mt. Fuji in Japan is the example of such volcanos.

iii) Extinct or Dead Volcano: Extinct Volcano are the volcanos which are permanently stopped the process of ejaculating lava, there is no activity in these volcanos hence these types of volcanos are known as dead volcano too. Mt. Kilimanjaro, Tanzania are the example of these types of volcanos.

4.) Explain the effects of Volcanoes.

Answer: Two types of effects we can see of volcanoes on the earth: Constructive effects of volcanoes and Destructive effects of volcanoes.

i) Constructive Effects of volcanoes: Volcano sometimes enrich the soil fertility and fertile soil causes increased agricultural activities. Another good effect of volcano is it helps to generate geothermal energy. Volcanoes are very attractive tourist spots for adventure loving tourists, it encourages tourism. Apart from it the materials from the volcanoes can be used to for construction, these are constructive effect of volcanoes.

ii) Destructive Effects of volcanoes: The destructive effect of volcanoes they cause earthquakes, floods, mud slide and rock fall. Lava flows long and it burns and buries everything it touches. Volcanoes cause dust and ash which makes the environment unable to breath and irritable. Volcano eruptions can change weather conditions and transportation gets affected in some of the areas.

Updated: July 20, 2021 — 9:50 pm

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