Samacheer Kalvi 6th Social Science Term 1 Geography Solutions Chapter 1 Pdf
Tamilnadu Board Samacheer Kalvi 6th Social Science Term 1 Geography Solutions Chapter 1: Tamilnadu State Board Solution Class 6 Social Science Term 1 Geography Chapter 1 – The universe and solar system.
Samacheer Kalvi 6th Social Science Geography Solutions Chapter 1: Overview
Board |
Samacheer Kalvi |
Class |
6 |
Subject |
Social Science Geography |
Term |
1 |
Chapter Name |
The universe and solar system |
Geography Unit 1: The universe and solar system
Multiple choice questions: (marks: 1)
1.) India is located in the continent of:
A.) Asia
B.) Africa
C.) Europe
Ans: Asia.
2.) Light travels at a velocity of:
A.) 30,000 km per second
B.) 300,000 km per second
C.) 330,000 km per second
Ans: 300,000 km per second.
3.) At the centre of the solar system, located:
A.) The Sun
B.) The Earth
C.) The Moon
Ans: The Sun.
4.) Which is the hottest planet among them:
A.) Mercury
B.) Saturn
C.) Venus
Ans: Venus.
5.) The Earth revolves around the Sun at a speed of about:
A.) 3 km per second
B.) 30 km per second
C.) 300 km per second
Ans: 30 km per second.
6.) The largest satellite of Neptune is:
A.) Triton
B.) Titania
C.) Europa
Ans: Triton.
7.) The largest satellite of Uranus is:
A.) Triton
B.) Titania
C.) Io
Ans: Titania.
8.) The Earth is:
A.) Spherical in shape
B.) Cylindrical in shape
C.) Circular in shape
Ans: spherical in shape.
9.) Assertion (A): Venus is called Earth’s twin. Reason(R): Venus is almost the same size as the Earth.
a.) Both A and R are true and R is the correct explanation of A.
b.) A is true but R is not the correct explanation of A.
c.) R is true but A is false.
d.) A and R are both false. e.
Ans: Both A and R are true and R is the correct explanation of A.
10.) Assertion (A): The Earth is called the ‘blue planet ‘/’ watery planet’.Reason(R): Three fourths of the earth’s surface is covered by water. So it seems blue from Space.
a.) Both A and R are true but R is not the correct explanation of A.
b.) Both A and R are true and R is the correct explanation of A.
c.) A is true but R is false.
d.) R is true but A is false.
Ans: Both A and R are true and R is the correct explanation of A.
11.) Assertion (A): Mars is called the red planet.
Reason(R): There is iron oxide present on the surface of Mars.
a.) Both A and R are true and R is the correct explanation of A.
b.) Both A and R are true but R is not the correct explanation of A.
c.) A is true but R is false.
d.) R is true but A is false.
Ans: Both A and R are true and R is the correct explanation of A.
12.) The solar system is believed to have formed about:
A.) 4 billion years ago
B.) 4.5 billion years ago
C.) 5 billion years ago.
Ans: 4.5 billion years ago.
13.) Sound travels at a speed of:
A.) 3 m per second
B.) 30 m per second
C.) 330 m per second
Ans: 330 m per second.
14.) The Gulf of Mannar Biosphere Reserve situated in:
A.) The Indian Ocean
B.) The Pacific Ocean
C.) The Atlantic Ocean
Ans: The Indian Ocean.
15.) Halley’s comet come close to the Earth on every:
A.) 66 years
B.) 76 years
C.) 86 years
Ans: 76 years.
16.) Assertion (A): Saturn is known as the ringed planet.
Reason(R): Saturn has many rings around it. These rings are huge and are mostly made up of ice, rocks and dust particles.
a.) Both A and R are true and R is the correct explanation of A.
b.) Both A and R are true but R is not the correct explanation of A.
c.) A is true but R is false.
d.) R is true but A is false.
Ans: Both A and R are true and R is the correct explanation of A.
Answer the following questions: (marks:1)
1.) What is the Universe?
Ans: The Universe is a vast expanse of space.
2.) The study of the universe is called what?
Ans: The study of the universe is called cosmology.
3.) What is the galaxy?
Ans: A galaxy is a huge cluster of stars which are held together by gravitational force.
4.) What is a light year?
Ans: A light-year is the distance travelled by light in a year.
5.) Which is the nearest galaxy to the Earth?
Ans: Andromeda galaxy is the nearest galaxy to the Earth.
6.) Which planet is the smallest and closest planet to the Sun?
Ans: Mercury is the smallest and closest planet to the Sun.
7.) Which planet has the longest rotation period among the planets in the solar system?
Ans: Venus has the longest rotation period (243 days) among the planets in the solar system.
8.) What is the only satellite of the Earth?
Ans: The Moon is the only satellite of the Earth.
9.) Write down the distance between the Earth and the Sun?
Ans: The distance between the Earth and the Sun is about 150 million km.
10.) Which is the largest planet?
Ans: Jupiter is the largest planet.
11.) Write down the names of the satellites of Mars?
Ans: phobos and deimos are tge satellites of Mars.
12.) Which planet have the largest number of natural satellites?
Ans: Jupiter have the largest number of natural satellites.
13.) Which planet is called the ringed planet?
Ans: Saturn is called the ringed planet.
14.) Which planet is called the somersaulting planet?
Ans: Uranus is called the somersaulting planet.
15.) Who discovered the plant Uranus?
Ans: Astronomer William Herschel discovered the planet Uranus in 1781.
16.) Uranus has……natural satellites.
Ans: 27.
17.) Neptune has……. natural satellites.
Ans: 14.
18.) Which planet is the coldest planet?
Ans: Neptune is the coldest planet.
19.) What are called satellites?
Ans: Satellites are celestial objects, which revolve around the planets.
20.) Write down the distance between the Earth and the Moon?
Ans: The distance between the Earth and the Moon is 3,84,000km.
21.) How long does it take for the Moon to revolve around the Earth?
Ans: Moon revolves around the Earth once every 27 days and8 hours.
22.) When did the first Moon mission launch?
Ans: ISRO launched India’s first ever Moon mission, Chandrayaan – 1 in 2008.
23.) What is called the Terminator line?
Ans: The line which divides the surface of the Earth into a lighted half and a dark half is called the Terminator Line.
24.) What is called equinoxes?
Ans: The equator faces the Sun directly on 21 March and 23 September. These two days are called Equinoxes, during which the day and nights are equal throughout the Earth.
25.) What is called orbit?
Ans: The elliptical path in which the planets move around the Sun is known as orbit.
26.) Saturn has………natural satellites.
Ans: 62
27.) Full forms: (1×3)
A.) ISRO: Indian Space Research Organization.
B.) MOM: Mars Orbiter Mission.
C.) NASA: National Aeronautics and Space Administration.
Answer the following questions: (marks: 2/ 3)
(1) What are called celestial bodies?
Ans: The Universe is a vast expanse of space. The universe consists of billions of galaxies, stars, planets, comets, asteroids, meteoroids and natural satellites. These are collectively called celestial bodies, which are located far away from each other. A Light year is the unit used to measure the distance between the celestial bodies.
(2) What is the Solar system?
Ans: The word ‘solar’ is derived from the Roman word ‘sol’, which means ‘Sun God’. The solar system is a gravitationally bound system which comprises the Sun, the eight planets, dwarf planets, satellites, comets, asteroids and meteoroids. The solar system is believed to have formed about 4.5 billion years ago.
(3) What are the planets of the Solar system?
Ans: The word ‘planet’ means wanderer.
There are eight planets in the solar system.
They are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.
(4) Write down the difference between terrestrial planets and jovian planets?
Ans:
Terrestrial planets: |
Jovian planets: |
● The four planets nearer to the Sun are called Inner or Terrestrial Planets | ● The last four planets are called Outer Planets or Jovian Planets . |
● The inner planets are comparatively smaller in size. | ● They are big in size so they are called Gaseous Giants. |
● Mercury, Venus, Earth and Mars are the inner or terrestrial planets. | ● Jupiter, Saturn, Uranus, and Neptune are jovian planets. |
(5) Which planet is called morning star and evening star and why?
Ans: Venus is known as morning star and evening star. Venus is often visible in the mornings and the evenings and so it is frequently called the Morning Star and the Evening Star.
(6) Why did Mangalyaan launch?
Ans: On 24th September, 2014 Mangalyaan launched by the Indian Space Research Organization (ISRO) and reached the orbit of Mars to analyze its atmosphere and topography.
(7) What is called a dwarf planet?
Ans: Dwarf planets are small celestial bodies found beyond the planet Neptune. They are extremely cold and dark. They are almost spherical in shape, but unlike planets they can share their orbit with other dwarf planets. The five dwarf planets of the solar system are Pluto, Ceres, Eris, Makemake and Haumea.
(8) What are asteroids?
Ans: Asteroids are small solid objects that move around the Sun. They are found as a belt between Mars and Jupiter. They are too small to be called planets. They are also known as Planetoids or Minor Planets.
(9) What are comets?
Ans: A comet is a celestial object made up of a head and a tail. The head of a comet consists of solid particles held together by ice and the tail is made up of gases. Halley’s Comet is the most famous comet which comes close to the Earth every 76 years. It appeared in 1986 and will appear in 2061.
(10) What are called meteors and meteorites?
Ans: A meteor is a stone-like or metallic body. When entering into the Earth’s atmosphere, most of them burn. As they often appear as streaks of light in the sky, they are also known as Shooting Stars. Meteors which strike the Earth’s surface are called meteorites.
(11) What is called the rotation of the Earth?
Ans: Rotation is the spinning movement of the Earth on its axis. The Earth rotates from west to east means anti-clockwise and takes 23 hours 56 minutes and 4.09 seconds to complete one rotation. The time taken by the Earth to complete one rotation is called a day. The rotation of the Earth causes day and night.
(12) Write down the reason behind one part of the Earth faces day and the other part faces night at the same time?
Ans: As the Earth is spherical in shape, only one half of it is illuminated by the Sun at a time. The other half remains dark. The illuminated portion of the Earth experiences day, whereas the darkened part of the Earth experiences night.
(13) What is called the revolution of the Earth?
Ans: Revolution is the movement of the Earth around the Sun on its elliptical path. The Earth takes 365 ¼ days to complete one revolution. It revolves around the Sun at a speed of 30 km per second. For the sake of convenience, we take it as 365 days and call it a year.
(14) What is a leap year?
Ans: The Earth takes 365 ¼ days to complete one revolution. It revolves around the Sun at a speed of 30 km per second. For the sake of convenience, we take it as 365 days and call it a year. The remaining quarter day is added once in every four years in the month of February. That is why February has 29 days once every four years. It is called a Leap Year. The inclination of the Earth on its axis and its revolution around the Sun causes different seasons.
(15) What do you know about the midnight Sun?
Ans: The Midnight Sun is a natural phenomenon that occurs in the summer months in places north of the Arctic Circle or south of the Antarctic Circle, when the Sun remains overhead 24 hours a day.
(16) What is perihelion and aphelion?
Ans: Perihelion is the Earth’s closest position to the Sun. Aphelion is the farthest position of the Earth from the Sun.
(17) What is known as the summer solstice?
Ans: Solstice is an occurrence when the Tropic of Cancer and Tropic of Capricorn face the Sun vertically. On 21st June, the Tropic of Cancer faces the Sun. This is known as the Summer Solstice. It is the longest day in the Northern Hemisphere and longest night in the Southern Hemisphere.
(18) What is known as the Winter solstice?
Ans: Solstice is an occurrence when the Tropic of Cancer and Tropic of Capricorn face the Sun vertically. On 22nd December, the Tropic of Capricorn faces the Sun. It is called the Winter Solstice. It is the longest day in the Southern Hemisphere and longest night in the Northern Hemisphere.
(19) Write down the difference between Earth’s rotation and revolution?
Ans:
Rotation |
Revolution |
● Rotation is the spinning movement of the Earth on its axis. | ● Revolution is the movement of the Earth around the Sun on its elliptical path. |
● It takes 23 hours 56 minutes and 4.09 seconds to complete one rotation. | ● Earth takes 365 ¼ days to complete one revolution. For the sake of convenience, we take it as 365 days. |
● The rotation of the Earth causes day and night. | ● Revolution of the Earth causes the changing of the seasons. |
(20) Atmosphere is made up of which gases?
Ans: Atmosphere is the envelope of air that surrounds the Earth. Different types of gases make up the atmosphere. The major gases are Nitrogen (78%) and Oxygen (21%). The other gases like Carbon dioxide, Hydrogen, Helium, Argon and Ozone are present in meager amounts.
(21) What is known as an ecosystem?
Ans: The narrow belt of interaction among the lithosphere, the hydrosphere and the atmosphere, where life exists is known as Biosphere. Biosphere consists of distinct zones. Bio means life in Greek. Each zone has its own climate, plant and animal life. These zones are known as ecosystems.
Answer the following questions: (marks: 5)
(1) Briefly discuss the solar system of the Earth.
Ans: The word ‘solar’ is derived from the Roman word ‘sol’, which means ‘Sun God’. The solar system is believed to have formed about 4.5 billion years ago. The solar system is a gravitationally bound system which comprises of the Sun, the eight planets, dwarf planets, satellites, comets, asteroids and meteoroids.
- The Sun:
The Sun is at the centre of the solar system. Each member of the solar system revolves around the Sun. The Sun is so huge, that it accounts for 99.8 percent of the entire mass of the solar system. The Sun is made up of extremely hot gases like Hydrogen and Helium. The Sun is a star. It is self-luminous; it gives light on its own. The surface temperature of the Sun is about 6,000° C. It is the source of light and heat energy to the entire solar system.
Sunlight takes about 8.3 minutes to reach the Earth.
- Planets:
The word ‘planet’ means wanderer. There are eight planets in the solar system. They are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. All the planets rotate anti-clockwise (from west to east) on their own axes except Venus and Uranus.
✓ Mercury: Mercury is the smallest and closest planet to the Sun. It is an airless and waterless planet. It does not have an atmosphere and so experiences extremes of temperature.
✓ Venus: Venus is the second planet from the Sun. It is called the Earth’s twin, as it is almost the same size as the Earth. It is also known as the hottest planet.
✓ Earth : Earth is called The Living Planet. The Earth is the third planet from the Sun and the fifth largest planet in the solar system. It is called the ‘blue planet’ or ‘watery planet’ because three-fourth of the Earth is covered by water. It is the only planet known to support life. Life is possible on Earth because of the presence of land, air and water. The Moon is the only satellite of the Earth.
✓ Mars: Mars is the fourth planet from the Sun and the second smallest planet in the solar system, after Mercury. It appears red in colour due to the presence of iron oxide on its surface. So, it is often described as theRed Planet.
✓ Jupiter: Jupiter is the fifth planet from the Sun and the largest planet in the solar system. It is the third brightest object in the night sky, after the moon and Venus. It is the fastest spinning planet in the solar system. It is called a gas giant planet.
✓ Saturn: Saturn is the sixth planet from the Sun and the second largest planet in the solar system, after Jupiter. Saturn has many rings around it. These rings are huge and are mostly made up of ice, rocks and dust particles.
✓ Uranus: It is known as the Somersaulting Planet. Uranus is the seventh planet from the Sun. It was the first to be discovered with a telescope by the astronomer William Herschel in 1781.
✓ Neptune: Neptune is the eighth and the farthest planet from the Sun. There are strong winds on this planet. Because of its distance from the Sun, Neptune is one of the coldest planets in the solar system.
- The Dwarf Planets:
Dwarf planets are small celestial bodies found beyond the planet Neptune. They are extremely cold and dark. They are almost spherical in shape, but unlike planets they can share their orbit with other dwarf planets. The five dwarf planets of the solar system are Pluto, Ceres, Eris, Makemake and Haumea.
- Asteroids:
Asteroids are small solid objects that move around the Sun. They are found as a belt between Mars and Jupiter. They are too small to be called planets. They are also known as Planetoids or Minor Planets.
- Comets:
A comet is a celestial object made up of a head and a tail. The head of a comet consists of solid particles held together by ice and the tail is made up of gases. Halley’s Comet is the most famous comet which comes close to the Earth every 76 years. It appeared in 1986 and will appear in 2061.
- Meteors and Meteorites:
A meteor is a stone-like or metallic body. When entering into the Earth’s atmosphere, most of them burn. As they often appear as streaks of light in the sky, they are also known as Shooting Stars. Meteors which strike the Earth’s surface are called meteorites.
(2) Write down a short note about the planets of the Solar system?
Ans: The word ‘planet’ means wanderer. There are eight planets in the solar system. They are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. All the planets rotate anticlockwise on their own axes except Venus and Uranus. The elliptical path in which the planets move around the Sun is known as orbit. The eight planets revolve in their respective orbits because of the gravitational pull of the Sun. They do not move out of their paths or away from the solar system.
- Mercury:
Mercury is the smallest and closest planet to the Sun. It is an airless and waterless planet. It does not have an atmosphere and so experiences extreme temperature. It has no natural satellites. Mercury can be viewed in the morning and evening with the naked eye.
- Venus:
Venus is the second planet from the Sun. It is called the Earth’s twin, as it is almost the same size as the Earth. It is also known as the hottest planet. It has the longest rotation period (243 days) among the planets in the Solar system. It rotates in the opposite direction to all other planets, except Uranus. It has no natural satellites, like Mercury.It is often visible in the mornings and the evenings and so it is frequently called the Morning Star and the Evening Star. After the Moon, it is the brightest natural object in the night sky.
- Earth:
The Earth is the third planet from the Sun and the fifth largest planet in the solar system. It is called the ‘blue planet’ or ‘watery planet’ because three-fourth of the Earth is covered by water. It is the only planet known to support life. Life is possible on Earth because of the presence of land, air and water. The Earth revolves around the Sun at a speed of about 30 km per second. The only natural satellite of the Earth is the Moon. The distance between the Sun and the Earth is about 150 million km.
✓ The Moon: Satellites are celestial objects, which revolve around the planets. The moon is the Earth’s only satellite. It revolves around the Earth once in every 27 days and 8 hours. It takes about the same time for it to complete one rotation around its axis. It has no atmosphere. The surface of the moon is characterized by craters created by the impact of meteors. The distance between the moon and the Earth is about 3, 84,400 km. The size of the moon is one-quarter of the Earth. The Moon is the only celestial body where humans have landed.
- Mars:
Mars is the fourth planet from the Sun and the second smallest planet in the solar system, after Mercury. It appears red in colour due to the presence of iron oxide on its surface. So, it is often described as the red Planet. It has a thin atmosphere. Mars has two natural satellites namely Phobos and Deimos. Many orbiters and rovers have been launched to explore this planet.
- Jupiter:
Jupiter is the fifth planet from the Sun and the largest planet in the solar system. It is the third brightest object in the night sky, after moon and Venus. It is the fastest spinning planet in the solar system. It is called a gas giant planet. Its atmosphere is mostly made up of Hydrogen and Helium like the Sun. It has the largest number of natural satellites. Io, Europa, Ganymede and Callisto are a few large satellites of Jupiter.
- Saturn:
Saturn is the sixth planet from the Sun and the second largest planet in the solar system, after Jupiter. Saturn has many rings around it. These rings are huge and are mostly made up
of ice, rocks and dust particles. Saturn has 62 natural satellites around it. Titan, Saturn’s largest moon, is the only Jupiter satellite in the solar system that has clouds and a dense atmosphere composed of nitrogen and methane. The specific gravity of Saturn is less than that of water.
- Uranus:
It is also known as the Somersaulting Planet.Uranus is the seventh planet from the Sun. It was the first to be discovered with a telescope by the astronomer William Herschel in 1781. It appears green due to the presence of methane gas. It is named after the Greek god of the sky. It rotates on its axis from east to west like Venus. Its axis is tilted so much that, it appears to orbit the Sun on its sides like a rolling ball. Uranus has 27 natural satellites, of which Titania is the largest.
- Neptune:
Neptune is the eighth and the farthest planet from the Sun. There are strong winds in this planet. Neptune has 14 natural satellites, the largest being Triton. Because of its distance from the Sun, Neptune is one of the coldest planets in the solar system.
(3) What are the spheres of the Earth? Briefly discuss about it. (1+4)
Ans: The Earth is the most suitable planet to support life. It has three major components that we call as the realms of the Earth- lithosphere, hydrosphere and atmosphere. The three components along with suitable climate make life possible on Earth. All living things exist in a narrow zone called the Biosphere. Let’s discuss about it:
Lithosphere:
The word lithosphere is derived from the Greek word Lithos, which means rocky. The Lithosphere is the land on which we live. It is the solid outer layer of the Earth consisting of rocks and soil.
Hydrosphere:
The word Hydro means water in Greek. The hydrosphere consists of water bodies such as oceans, seas, rivers, lakes, ice caps on mountains and water vapour in the atmosphere.
Atmosphere:
The word Atmo means air in Greek. Atmosphere is the envelope of air that surrounds the Earth. Different types of gases make up the atmosphere. The major gases are Nitrogen (78%) and Oxygen (21%). The other gases like Carbon dioxide, Hydrogen, Helium, Argon and Ozone are present in meager amounts.
Biosphere:
The narrow belt of interaction among the lithosphere, the hydrosphere and the atmosphere, where life exists is known as Biosphere. Bio means life in Greek. It consists of distinct zones. Each zone has its own climate, plant and animal life. These zones are known as ecosystems.
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