CBSE 8th VIII Physics Ch-Universe stars and planets Questions with solution
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1. Name the natural satellite of earth.
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Answer: Moon is the only natural satellite of earth.
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2. Define one light year.
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Answer: One light year is the distance travelled by light in one year at the speed of light.
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3. Why are the stars not visible during day time?
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Answer: The stars are not visible during the day because of the glare of bright sunlight.
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4. What is a pole star?
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Answer: Pole star is a star that is situated in the north direction and appears stationary to us.
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5. What is the total number of planets in our solar system? Name them
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Answer: There are nine planets in our solar system. These are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto.
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6. Which planet is known as morning and evening star? Why is it so called?
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Answer: Mercury is known as morning and evening star. It is because it becomes visible just before sunrise or immediately after the sunset and appears like a very bright star.
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7. Which day is longest and smallest in the northern and southern hemisphere?
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Answer: On June 21, the earth is farther away from the sun than on December 22. On this day we have the longest day in the northern hemisphere while it is the shortest in the southern hemisphere.
On December 22, the length of the day is the shortest in the northern hemisphere and longest in the southern hemisphere.
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8. What are the asteroids?
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Answer: There is a large gap in between the orbits of the Mars and Jupiter. This gap is occupied by a large number of small bodies that revolve around the sun. These are called asteroids
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9. Differentiate between meteors and meteorites.
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Answer: Meteors are very small stone like objects that are revolving around the sun. When a meteor enters the atmosphere of the earth, it gets heated due to friction of air. The heat produced is so high that meteors begins to glow and evaporates within a short time.
Some meteors are so large that a part of them reaches the surface of the earth before they get evaporated completely, these are known as meteorites
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10. Write a short note on constellation.
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Answer: Many a time, a group of stars as seen from the earth, appears to form some kind of pattern. Our ancestors imagined some known shapes formed by many groups of stars and gave them specific names. Such a group of stars is known as a constellation. Some easily identifiable constellations are Ursa Major or Vrihat Saptarshi, Ursa Minor or Laghu Saptarshi and Orion or Mriga.
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11. Give some practical applications of artificial satellites.
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Answer: Artificial satellites have many particle applications. Long distance transmission of television programmes, communication through telephones and internet could be possible because of them. Artificial satellites are also used for research, defense and remote sensing. Some artificial satellites are also used to gather information about the movements of materials concerning defense activities.
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12. Differentiate among Ursa and Ursa minor by drawing their relative positions of stars.
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Answer : Ursa Major or Vrihat Saptarshi is known as Big Dipper. The Big Dipper is a group of many stars of which seven are comparatively brighter and are easily visible. It appears like a big ladle or a question mark. Ursa minor or Small dipper also has seven prominent stars in it. These constellations are usually visible during springs from our part of the world.
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20 September 2011
class 8 chapter The Universe Test Paper
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Our Universe - Basic science class 8 Bharati Bhawan Publication
ReplyDeleteA1.Is light year a unit of time or distance? Define `1 light year?
Ans: Light year is a unit of distance .one light year is a distance covered by light in 1 year.
A2.What is the source of stars energy?
Ans: The source of stars energy is nuclear fusion in which hydrogen atoms split up into helium atoms and large amount of energy is librated.
A3.What gives galaxies different shapes? Name a few common shapes of galaxies.
Ans: The arrangement of stars gives galaxies different shapes of galaxies. About 100 billians galaxies in the universe some of them are in shape of spiral, ring like or elliptical.
A4.What is the big Dipper?
Ans: The seven brightest stars in between the month of February and may form a shape of dipper in northern sky. This constellation is called Big deeper or Saptarshi.
A5. Why are Mercury venues, and Mars called terrestrial planets?
Ans: This is because they are closest to sun and rocky like earth.
A 6. Name the planet which have ring around them?
Ans: Saturn, Jupiter , Uranus and Neptune
A7. What is the huge spot on Jupiter?
Ans: This spots are actually a huge storm, which has been ranging on Jupiter for more than 300 years
A8. Name two dwarf planets?
Ans: Ceres and Eris
A9. How do dwarf planets different from other planets?
Ans: dwarf planets are not able to pull in the object (gravitational force) near its orbit at the time of its formation
A10.Why do scientists think that Mars had liquid water in the past?
Ans: Scientists think that Mars had liquid water in the past as the channels visible on its surfaces.