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TN Board Class 6 Social Science Unit 1 The Universe and the Solar System

If you are looking for Tamil Nadu Board Class 6 Social Science Unit 1 The Universe and the Solar System then you are at the right place. Here we are providing solutions as well as additional QA / Important Notes.


Fill in the blanks

  1. The Universe was formed after…..explosion.[Big Bang]
  2. …….is the unit used to measure the distance between two celestial bodies.[Light Year]
  3. …….is the centre of the solar system.[Sun]
  4. The word planet means ……….[Wanderer]
  5. ……….planet has many natural satellites.[Jupiter]
  6. India’s first ever mission to the moon is …………[Chandrayaan-1]
  7. Earth is inclined by ………..degrees.[23.5]
  8. The Equator faces the Sun directly on……….and……………[March 21 & Sept. 23]
  9. At the time of Perihelion, the Earth is……….. to the Sun.[closest]
  10. The line which divides day and night on the Earth’s surface is …………[the Terminator Line]


Choose the best answer


The movement of the Earth on its axis is called

  • Revolution
  • Seasons
  • Rotation
  • Circulation


The Tropic of Capricorn faces the Sun directly on

  • March 21
  • June 21
  • September 23
  • December 22


The galaxy in which our solar system is found is

  • Andromeda
  • Magellanic clouds
  • Milky Way
  • Starburst


The only celestial body where man has successfully landed

  • Mars
  • Moon
  • Mercury
  • Venus


Which of the following planets can float on water?

  • Jupiter
  • Saturn
  • Uranus
  • Neptune


Circle the odd one out

  • Venus, Jupiter, Neptune, Saturn [Venus is a terrestrial planet, the others are gas giants.]
  • Sirius, Andromeda, Milky way,Magellanic clouds.[Andromeda, Milky Way, and Magellanic Clouds are galaxies, Sirius is a star.]
  • Pluto, Eris, Ceres, Io [Io is a moon, the others are dwarf planets.]
  • Comet, Asteroids, Meteorites, Dwarf planets [Dwarf planets are larger celestial bodies, the others are smaller objects.]
  • Rover, Orbiter, Aeroplane, Space shuttle. [Aeroplane is not used for space exploration, the others are.]


Match the following

  • Hottest Planet – a. Mars
  • Ringed Planet – b. Neptune
  • Red Planet – c. Venus
  • Somersaulting Planet – d. Saturn
  • Coldest Planet – e. Uranus


  • Hottest Planet – c. Venus
    Ringed Planet – d. Saturn
    Red Planet – a. Mars
    Somersaulting Planet – e. Uranus
    Coldest Planet – b. Neptune


Consider the following statements

  1. Venus rotates from east to west.
  2. The Tropic of Cancer faces the Sun on June 21.
  3. Mars has rings around it.

Choose the correct answer using the codes given below.

  • 1 and 2
  • 2 and 3
  • 1, 2 and 3
  • 2 only


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

Statement I: Earth is called a watery planet.

Statement II: The rotation of the Earth causes seasons.

  • I is true; II is wrong
  • I is wrong; II is true
  • Both the statements are true
  • Statements I and II are wrong.


Name the following

  • Cluster of stars. [Galaxy]
  • The nearest galaxy to the solar system.[Andromeda galaxy]
  • The brightest planet.[Venus]
  • The living sphere.[Biosphere]
  • The year which has 366 days.[Leap Year]


Answer in brief


Name the inner planets.

The inner planets, also known as terrestrial planets, are Mercury, Venus, Earth, and Mars.


Pluto is no longer a planet. Reason out.

Pluto is no longer classified as a planet because it does not meet all the criteria set by the International Astronomical Union (IAU) in 2006. Specifically, Pluto has not cleared its neighboring region of other objects. It shares its orbit with other objects in the Kuiper Belt, thus failing the criterion of “clearing the neighborhood” around its orbit, which is essential for full planetary status. Therefore, Pluto is classified as a dwarf planet.


What is perihelion?

Perihelion is the point in the orbit of a planet or other celestial body where it is closest to the Sun. For Earth, perihelion occurs around January 3rd each year.


How many times in a year would you find the Sun overhead if you lived on 20°N Latitude?

If you lived on 20°N Latitude, you would find the Sun directly overhead twice a year. This occurs when the Sun’s declination is exactly 20°N, once during its northward movement (around late April) and once during its southward movement (around mid-August).


Which celestial body shares its orbit with others? Give an example.

Dwarf planets can share their orbits with other celestial bodies. An example is Pluto, which shares its orbit with objects in the Kuiper Belt.


Give reasons.


Why is Uranus called the somersaulting planet?

Uranus is called the somersaulting planet because of its unique axial tilt. Its axis is tilted by about 98 degrees, which means it essentially rotates on its side. This extreme tilt causes Uranus to appear as if it is rolling along its orbit around the Sun, unlike any other planet in the solar system.


The surface of the moon has many craters.

The surface of the moon has many craters because it lacks an atmosphere. Without an atmosphere, there is no air resistance to slow down or burn up meteoroids before they impact the surface. As a result, meteoroids and other space debris collide with the Moon’s surface directly, creating numerous craters over billions of years.

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