NCERT Exemplar for Class 8 Science Solutions Chapter 17 Stars and Solar System

Multiple Choice Questions

1. Morning star is the name given to 

(a) Pole star 

(b) Star Sirius 

(c) Planet Jupiter

(d) Planet Venus 

Ans: (d) Venus is a planet that rises before the sun in the east. 

2. Which of the following figures depicts the position of pole star correctly?

Ans: (a) Pole star is located on the north pole of the earth’s axis. 

3. Sun appears to move from east to west around the earth. This means that earth rotates from 

(a) East to west 

(b) West to east 

(c) North to south 

(d) West to north

Ans: (b) Earth is rotating in the opposite direction that is from the North to South as sun appears to move east to west. 

4. An astronaut standing on the surface of the moon throws a ball upwards. The ball would 

(a) Directly fall down from the point it is released. 

(b) Hang in space. 

(c) Go up and then come back to the surface of the moon. 

(d) Keep going up never to come back. 

Ans: (c) Due to less gravitational force on the moon, the acceleration is also less, therefore the ball first goes up and then comes down. 

5. Suppose a new planet is discovered between Uranus and Neptune. 

Its time period would be

(a) Less than that of Neptune. 

(b) More than that of Neptune. 

(c) Equal to that of Neptune or Uranus. 

(d) Less than that of Uranus. 

Ans: (a) The period of time would be more than the Uranus but lesser than the Neptune because the period of time is directly proportional to the distance from the sun. 

6. The change in seasons on the earth occurs because 

(a) The distance between the earth and the sun is not constant. 

(b) The axis of rotation of the earth is parallel to the plane of its orbit. 

(c) The axis of rotation of the earth is perpendicular to the plane of its orbit. 

(d) The axis of rotation of the earth is tilted with respect to the plane of its orbit. 

Ans: (d) Axis of rotation is not at a 90 degree slant to the planet of its orbit. Therefore, the change in season is due the tilt in the axis of rotation of the earth with respect to plane of its orbit.

7. The first day of the month is the new moon day. On fifteenth of the same month, which of the following figures would represent the phase of the moon?

Ans: (a) On the fifteenth day of the same month, the new moon day is full moon day. 

Very Short Answer Questions

8. Do stars emit light only during night? 

Ans: No, the stars radiate light throughout the day, however the light of the stars is obscured by the sun's brilliance.

9. Paheli and Boojho observe a bright object in the night sky which was not twinkling. Paheli says it is a star and Boojho says it is a planet. Who is correct? 

Ans: Paheli is wrong and Boojho is right. Because planets do not twinkle and stars always emit their light and twinkle. 

10. State whether the following statements are ‘True’ or ‘False’. 

(a) The planet nearest to us is Jupiter. 

Ans: False because Venus and Mars are the planets nearest to earth. 

(b) All the stars are at the same distance from us. 

Ans: False because different stars are at distance from us 

(c) The planets do not emit light of their own. 

Ans: True 

(d) The planets keep changing their position with respect to stars. 

Ans: True 

(e) The planet Venus appears in the eastern sky before sunrise. 

Ans: True 

(f) The plane in which the earth revolves around the sun is called the equatorial plane of earth. 

Ans: False because Earth revolves around the sun in a plane orbit. 

11. John saw the full moon on a particular day. After how many days will he be able to see the full moon again? 

Ans: John will be able to see the full moon again approximately after 29 days. 

12. In the picture of rotating earth given as Fig. 17.3 mark the position of the pole star.

Ans:

13. In the given Fig. 17.4 out of the positions A,B,C and D which will indicate the position of the sun? Draw the sun at the appropriate position.

Ans:

14. In Fig. 17.5 mark the arrows (←), (→), (↓), or (↑) to show the direction of sunlight.

Ans: Because the sun is to the right of the globe, its rays fall from right to left on the planet.

Short Answer Questions

15. A star is ten light-years away from the earth. Suppose it brightens up suddenly today. After how much time shall we see this change? 

Ans: The distance travelled by light in a year is measured in light-years. After ten years, we will be able to glimpse a star that is 10 light-years away from the Earth.

16. Meteors are not visible during the daytime. Explain the reason. 

Ans: A meteor is defined as any celestial body that enters the Earth's atmosphere. Meteors are also known as shooting stars and they are not visible during the day because of the brightness of the sun. A shooting star is visible only at night because it glows upon coming in contact with the atmosphere of the earth. 

17. Why does the moon change its shape daily? 

Ans: We know that the Moon is visible to us because of the light produced by the Sun and that moon is revolving around the earth. That means at a time only a portion of the moon is enlightened by the Sun and that enlightened portion could only be seen from Earth. Thus, to us, it looks like the moon is changing its shape every day. 

18. Paheli saw the moon through a glass window at 8:00 p.m. She marked the position of the moon on the glass pane. She got up at 4 a.m. in morning. Will the moon be visible at the same position? 

Ans: No, Paheli will not be able to locate the moon at 4 a.m. in the morning where she had located it earlier because just like the Earth rotates on its axis and revolves around the Sun, so does the moon around the Earth. So, the moon had travelled a certain distance around the Earth. 

Long Answer Questions

19. Suppose the moon emits light of its own. Would it still have phases? Justify your answer. 

Ans: No, there will not be phases if the moon had its own emitting light, it will be visible to us just like the Sun. Currently, the surface of the moon is illuminated by the Sun which makes only a certain portion of the moon visible. 

20. Fig. 17.6 shows comets without their tails. Show the tails of the comets at positions A, B, and C. In which position will the tail be longest?

Ans: The tail will be longest at position B as it is the closest point from the sun because the comet’s tail is observable only when it goes by the inner orbit of the solar system.

21. Explain why we always see the same side of the moon. 

Ans: We know that the Moon is visible to us because of the light produced by the Sun and that moon is revolving around the earth. That means at a time only a portion of the moon is enlightened by the Sun and that enlightened portion could only be seen from Earth.

22. Look at Fig. 17.7 carefully and answer the following question: 

(a) In which part of the sky would you see the full moon in the evening? 

Ans:In the evening, the full moon shines brightly in the eastern sky. 

(b) In which part of the sky would you see the crescent moon in the evening?

Ans: In the evening, the crescent moon (which is shaped like a sickle) is visible in the western sky.

23. Write the names of all planets in Fig. 17.8. 

Ans: Names of the planet are- 

i. Mercury. 

ii. Venus 

iii. Earth 

iv. Mars 

v. Jupiter 

vi. Saturn 

vii. Uranus 

viii. Neptune 

24. Suppose the distance between earth and sun becomes half of its present distance. What is likely to happen to life? 

Ans: As we know, the distance between the Sun and the Earth is sufficient, but still we suffer from the radiation and the temperature of the earth‟s surface is high. So, if the distance between earth and sun becomes half of its current distance, there would be no life on earth as the earth will heat up soon, the water may dry up soon and the vegetation will be destroyed too. 

25. Explain with a diagram how you can locate a pole star with the help of the constellation Great Bear (Ursa Major). 

Ans: The “Great Bear” or the “Ursa Major” is one of the constellations present in the northern part of the sky.

We can position the pole star from the Ursa Major, by locating two stars of the constellation and drawing an imaginary line between the two stars (as drawn in figure). Next, we extend this imaginary line towards the north direction which will eventually bring us to the less brightened star, known as Pole Star.

About the Chapter

The Solar System assists you in learning about the various types and levels of complexity of all potential types of questions that can be asked on the subject of The Solar System. The NCERT Exemplar Class 8 Science Solutions Chapter 17 Stars and Solar System are based on the latest CBSE syllabus 2024-25 and were created by top subject specialists. There are seven multiple-choice problems on this page, as well as seven very quizzes, four short answer questions, and seven long answer questions.

Pupils in the sixth grade have extensively reviewed the solar system. Students in Class 8 will study astronomical objects such as the moon, stars, constellations, sun, and planets. Understanding our solar system is crucial since space may be humanity's final frontier. To comprehend the topic and achieve good exam results you must use the NCERT Exemplar Class 8 Science Solutions Chapter 17 Stars and Solar System to answer problems.

NCERT Exemplar Class 8 Science Solutions Chapter 17 Stars and Solar System Covers the Following Topics: 

• The Solar System and the Stars

• The Moon as a celestial body

• The Stars

• Constellations

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