The Earth and The Universe 8

 

The Earth and The Universe

Group A

Multiple Choice Questions.

Circle the correct answer to the following questions.

1.      Which of the following is a metallic mineral?

a) haematite              b) graphite                

c) diamond                 d) silica

2.      Which of the following is ferrous minerals?

a) chalcopyrite                 b) magnetite

c) Bouxite                         d) argentite

3.      Which of the following is not the property of minerals?

a) Minerals exist in various colours.

b) Minerals have fixed geometric shape.

c) Minerals are found in solid state.

d) Metallic minerals are bad conductors of heat and electricity.

4.      How much distance does light travel in one year?

a) 9.46×10¹⁵ km                b) 9.46×10¹⁵m

c)  9.46×10¹² cm                b) 9.46×10¹²m

5.      Long ago, a giant comet moving around the universe collide with the sun as a result planets like earth and satellite formed. This statement is related to which of the following principle?

a) Nebular hypothesis                 b) binary hypothesis

c) Planetesimal hypothesis         d) tidal hypothesis

6.      In which era the dinosaurs are found to be evolved and developed?

a) Palaezoic era                            b) Cryptozoic era

c) Cenozoic era                             d) Mesozoic era

7.      In which era has the mammals evolved?

a) Palaezoic era                            b) Cryptozoic era

c) Cenozoic era                             d) Mesozoic era

8.      Which era is identified as the age of conifers?

a) Palaezoic era                            b) Cryptozoic era

c) Cenozoic era                             d) Mesozoic era

9.      Which of the following mass is identified as shooting star?

a) meteor                                     b) galaxy

c) asteroid                                    d) comet

10.  Which of the following is asteroid?

a) Shoemaker-levy                      b) Andromeda

c) Vela                                           d) Ceres

11.  How many constellations are identified yet?

a) 76                                              b) 88

c) 9                                                d) 12

12.  What is called for the region in the sky with some stars making a particular pattern?

a) galaxy                                       b) meteor

c) Constellation                            d) asteroid

13.  a

Answer: 1(a), 2(b), 3(d), 4(b), 5(d), 6(d), 7(c), 8(d), 9(a), 10(d), 11(b), 12(c)

Group B

Very Short answer Questions.

    1.      What is energy minerals?
→ Minerals that are used to generate energy, such as coal, petroleum, and uranium.

    2.      Give an example of a non-metallic mineral.
→ Example: Graphite, Quartz, or Mica.

    3.      Write the names of the eras in which the first green plant and crocodile evolved on Earth.
→ First green plant: Palaeozoic era
→ Crocodile: Mesozoic era

    4.      Name the era in which fishes and human beings originated on Earth.
→ Fishes: Palaeozoic era
→ Human beings: Cenozoic era

    5.      What is the Cenozoic era?
→ The Cenozoic era is the "Age of Mammals," during which modern mammals, birds, and humans evolved.

    6.      In which era were frogs and horses evolved?
→ Frogs: Mesozoic era
→ Horses: Cenozoic era

    7.      What is the estimated age of the Earth?
→ Approximately 4.6 billion years.

    8.      In which era did dinosaurs and humans evolve?
→ Dinosaurs: Mesozoic era
→ Humans: Cenozoic era

    9.      In which era were dinosaurs evolved and what was the duration of that era?
→ Era: Mesozoic era
→ Duration: About 252 to 66 million years ago.

    10.  Write the names of the eras of existence of fern and coniferous plants.
→ Fern: Palaeozoic era
→ Coniferous plants: Mesozoic era

    11.  What is a galaxy? In which galaxy does our solar system fall?
→ A galaxy is a large system of stars, gas, and dust bound together by gravity.
→ Our solar system is in the Milky Way galaxy.

    12.  Write the names of two asteroids.
→ Ceres and Vesta.

    13.  What is a constellation? Give an example of a constellation.
→ A constellation is a group of stars forming a recognizable pattern in the sky.
→ Example: Orion, Ursa Major, or Cassiopeia.

    14.  What is a meteor shower?
→ A meteor shower occurs when many meteors enter Earth's atmosphere and burn up, appearing as streaks of light in the sky.

    15.  Name a constellation which can be seen with naked eyes.

→ Great bear (Saptarishi)  is the constellation which can be seen with naked eyes.

    16.  Which era is called the time reptiles?

→ Mesozoic era is called the time of reptiles.

    17.  In which era did non-flowering plants evolve?

→ Non-flowering plants evolved in Paleozoic era.

    18.  Write the name of any two comets.

Name of any two comets are Halley's Comet and Shoe-maker Levy

    19.  What is universe?

Universe is a vast space which occupies all the matter, galaxy, constellation, meteors, asteroids, etc.

    20.  Which era is called the age of mammals?

Cenozoic era is called the age of mammals.

Group C

Short answer questions.

1.      Write any two differences between Mesozoic era and Cenozoic era.

Two differences between Mesozoic era and Cenozoic era:

Mesozoic Era	Cenozoic Era
Known as the Age of Reptiles (Dinosaurs dominated).	Known as the Age of Mammals (Mammals became dominant).
Existed about 252 to 66 million years ago.	Started about 66 million years ago and continues today.

 

2.      Living beings were evolved very long after the Earth was evolved, why?

→ At the beginning, Earth was extremely hot, with a harmful atmosphere and there was no oxygen. The temperature get cooled after million years and  water bodies were formed, and oxygen levels increased, making conditions suitable for life to evolve.

3.      Mention the hypothesis propounded by Jean and Jeffery about the origin of the solar system.

→ Sir James Jeans and Harold Jeffery proposed a hypothesis called Tidal hypothesis. According to this hypothesis a star passing near the sun pulled material from the Sun due to gravitational force, which later condensed to form planets.

4.      Write any two differences between meteor and meteorites.

  Two differences between Mesozoic era and Cenozoic era:

Mesozoic Era	Cenozoic Era
Known as the Age of Reptiles (Dinosaurs dominated).	Known as the Age of Mammals (Mammals became dominant).
Existed about 252 to 66 million years ago.	Started about 66 million years ago and continues today.

5.      Meteorites are considered to be important for the scientists, why?

→ Meteorites provide clues about the early solar system, the composition of celestial bodies, and the possible origins of life on Earth. So, meteorites are considered to be important for the scientists.

6.      Comet is seen at a gap of long period, why?

→ Comets have highly elongated orbits, means they travel far away from the Sun and return only after decades or even centuries. When they come closer to the sun after decades or centuries, they are visible from the earth. So comet is seen at a gap of long period.

7.      The tail of the comet looks longer when it is nearer to the sun and shorter when it is away from the sun. Give reason.

→ The Sun's heat and solar wind cause the comet’s ice to vaporize, forming a longer tail when near the Sun. When the comet moves far away from the Sun, there is less heat, so the tail condenses and shrinks. As a result, tail of a comet looks nearer to the sun and shorter when it is away from the sun.

8.      Write any two differences between comet and meteors.

 Two differences between comet and meteor:

Comet	Meteor
Made of ice, dust, and gas and has a glowing tail when near the Sun.	A small rocky fragment that burns in Earth's atmosphere as a shooting star.
Has an elliptical orbit around the Sun and reappears after long periods.	Appears randomly and lasts for only a few seconds in the sky.

9. Why are galaxies more important than other celestial bodies to study the origin of the universe?
   → Galaxies contain billions of stars, nebulae, and cosmic materials, helping scientists study the formation, evolution, and expansion of the universe. They provide insight into the Big Bang Theory and cosmic evolution.
10. Mention the era in which the following animals and plants originated and developed on Earth.
    a) Flowering plants: Mesozoic era
    b) Man: Cenozoic era
11. Two reasons behind the development of mammals in the Cenozoic era:
    → (i) Extinction of dinosaurs in the Mesozoic era reduced competition, allowing mammals to thrive.
    → (ii) Favorable climate and the diversification of plant life supported mammalian evolution.
12. Mention any two reasons for the origin of living beings on Earth:
    → (i) Presence of water – Essential for biochemical reactions.
    → (ii) Formation of a suitable atmosphere – Oxygen and other gases supported life.
13. Write two differences between metallic and non-metallic minerals:

Metallic Minerals	Non-Metallic Minerals
Contain metals and can be melted to obtain pure metal.	Do not contain metals and lack metallic properties.
Good conductors of heat and electricity.	Poor conductors of heat and electricity.
Example: Iron, Copper	Example: Graphite, Quartz

14. Name Four important minerals found in Nepal:

Four important minerals found in Nepal are: (i) Iron ore,  (ii) Copper
(iii) Limestone  (iv) Gold

15. Write two uses of non-metallic minerals:
    (i) Limestone is used in cement production.
    (ii) Mica is used in electrical insulation.
16. How was Earth formed according to the Tidal Hypothesis?
    → According to the Tidal Hypothesis by Jeans and Jeffery, a massive star passed near the Sun, pulling out gaseous material due to gravitational force. These materials later condensed and formed planets, including Earth.
17. Write two uses of minerals. Two uses of minerals:
    → (i) Iron ore is used in making steel.
    → (ii) Copper is used in electrical wiring.
18. 14. Why are most meteors completely destroyed after revolving around the Sun?
        → Due to high-speed entry into Earth's atmosphere, friction causes them to burn up, leaving only a bright streak of light (shooting star).
19. Write four hypothesis regarding the origin of the Earth.

Four hypotheses regarding the origin of the Earth:
→ (i) Nebular Hypothesis
→ (ii) Tidal Hypothesis
→ (iii) Planetesimal Hypothesis
→ (iv) Big Bang Theory

20. Explain 'meteor shower' and 'observable universe'.
    → Meteor Shower: A celestial event where many meteors enter the Earth's atmosphere at high speed, burning up and creating streaks of light.
    → Observable Universe: The portion of the universe that we can observe from Earth, limited by the speed of light and cosmic expansion.
21. Write two differences between Paleozoic Era and Cenozoic Era.

Two differences between Palaeozoic era and Cenozoic era:

Palaeozoic Era	Cenozoic Era
Era of early marine life, fish, and amphibians.	Era of mammals and human evolution.
Occurred 541 to 252 million years ago.	Started 66 million years ago to present.

22. Why are minerals said to be pure chemicals?
    → Minerals have a definite chemical composition and crystalline structure, making them pure natural compounds.
23. Why is the Mesozoic era called the era of coniferous plants?
    → During the Mesozoic era, coniferous plants (gymnosperms) dominated the land, making it the "Age of Conifers."
24. What are minerals? Give examples.
    → Minerals are naturally occurring inorganic substances with a fixed chemical composition and crystalline structure.
    → Examples: Iron ore, Copper, Quartz, Mica.
25. Write two differences between galaxy and constellation.

Two differences between galaxy and constellation:

Galaxy	Constellation
A vast system of stars, gas, and dust bound by gravity.	A group of stars forming a recognizable pattern.
Example: Milky Way Galaxy	Example: Orion, Ursa Major

26. Write two differences between asteroid and comet.

Two differences between asteroids and comets:

Asteroids	Comets
Made of rock and metal.	Made of ice, dust, and gas.
Do not have a tail.	Develop a tail when near the Sun.
Example: Ceres, Vesta	Example: Halley’s Comet

27. Why are near-Earth asteroids dangerous for our planet?
    → Near-Earth asteroids can collide with Earth, causing massive destruction, climate changes, and even extinction events, like the one that wiped out the dinosaurs.
28.