Important Questions Class 8 Science Chapter 17

Important Questions Class 8 Science Chapter 17 – Stars and the Solar System

Chapter 17 of CBSE Class 8 Science syllabus is about Stars and the Solar System. This chapter explains some important topics, such as-

• The Moon.
• The Stars.
• Constellations.
• The Solar System.
• Some Other Members of the Solar System.

Students studying science should start by going through the Class 8 Science NCERT textbook. Science is a practical subject, so along with learning the theory behind it, students can enhance their knowledge by solving various chapter-end questions from the NCERT textbooks.

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Our subject matter experts understand the importance of solving questions for students to have on the subject. We thus provide students with a question bank of Important Questions for Class 8 Science Chapter 17 from the CBSE syllabus. Our team refers to NCERT books, other important reference books, CBSE sample papers, CBSE past year’s question papers, etc., to make a list of questions. Our question bank of Class 8 Science Chapter 17 Important Questions comes with detailed and step-by-step instruction-based solutions that are developed by our expert Science faculty members. Solving a large number of questions from our Important Questions for Class 8 Science Chapter 17 will help students feel prepared and confident when answering questions on their final exams.

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Important Questions Class 8 Science Chapter 17 – With Solutions

To help students with their studies and revisions Extramarks provides a comprehensive set of study materials. One critical element for holistic preparation is solving a lot of past years’ question papers. Students are recommended to refer to our question bank of Important Questions Class 8 Science Chapter 17 to improve their preparation for Class 8 Science and come out with flying colours.

Here are a few questions and their solutions from our question set of Important Questionnaires Class 8 Science Chapter 17.

Question 1. Write a short note on Ursa Major.

Answer 1. Ursa Major is a constellation seen in the night sky. It is also called the Big Dipper, The Great Bear or The Saptarishi. This constellation consists of seven easily seen stars. This constellation helps in locating the Pole star.

Question 2. Why do you think the moon’s phases are important in social life?

Answer 2. The moon’s phases are significant in our social lives since the moon’s phases hold most Indian festivals. Diwali, for example, is celebrated on the new moon day, whereas Budha Poornima and Guru Nanak’s birthdays fall on the full moon days. On the thirteenth night of the diminishing moon, Shivratri is observed. Eid Ul-Fitr is observed the day after the appearance of the crescent moon. Not only the festivals, but many people in Ayurveda also relate the moon’s phases with human health.

Question 3. Briefly describe the surface of the moon.

Answer 3. The moon’s surface is dusty and dried. There are several craters of different sizes. There are several stiff and high mountains in the area. Some of these are as tall as the world’s highest mountains.

Question 4. Define the following terms. 

• Orbit. b. Period of revolution.

Answer 4. a. Orbit- A planet has a definite path in which it revolves around the sun. This path is called an orbit.

1. Period of revolution- The time taken by a planet to complete one revolution is called it’s period of revolution.

Question 5. Correct the given statements- 

1. The moon has various layers of atmosphere and no water. 
2. Stars do not emit light on their own.

Answer 5. a. The moon has no atmosphere and  no water.

1. Stars emit their light and shine bright in the night sky.

Question 6. Why does the pole star look stationary from the earth?

Answer 6. From all locations on the planet, the pole stars appear to be stationary. This is because it is located on the line parallel to the earth’s axis of rotation. Pole star is located in the north. Hence when we can see the pole star straight above us, it appears stationary.

Question 7. Write a short note on comets.

Answer 7. Comets are members of our solar system. They have enormously elliptic orbits around the sun. On the other hand, their time of revolution around the sun is usually quite long. A comet is distinguished by a luminous head and a long tail; as it comes closer to the sun, the length of the tail increases. A comet’s tail is always situated away from the sun.

Question 8. What do you know about ‘Mangalyaan’?

Answer 8. ISRO launched India’s first interstellar space mission which was called Mangalyaan. After the success of NASA, Roscosmos, and the European Space Agency, India was the fourth country in the world to reach planet Mars orbit. And it was the first country from Asiat to do so. On September 24, 2014, the Mangalyaan was successfully established into Mars orbit. On this date, India became the first country across the world to accomplish this difficult goal on its first attempt.

Question 9. Give any four examples of artificial satellites.

Answer 9. Some Indian artificial satellites are as follows-

1. IRS-1B (1991)
2. INSAT-2DT (1992)
3.  INSAT-2A (1992)
4. Mars Orbiter Mission (2013)
5. Chandrayaan-2 (2019)

Question 10. Describe the arrangement of stars in the Orion constellation.

Answer 10. Orion is a well-known worldwide constellation placed on the celestial equator. It consists of seven bright stars. Hunter is another name for Orion. Three stars in the centre form a belt, and four bright stars are arranged in a quadrilateral formation.

Question 11. Write the names of eight planets in the order of their distance from the sun.

Answer 11. The eight planets in the solar system are – Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

Question 12. What are asteroids, meteors and meteorites?

Answer 12.

Asteroids – A huge number of tiny objects that spin around the sun occupy the space between Mars and Jupiter’s orbits, known as the asteroid belt.

Meteors and Meteorites – Meteors are defined as the tiny objects from space that reach  the Earth’s atmosphere in a few rare scenarios. Due to Earth’s gravitational force it enters the Earth’s atmosphere with a very fast speed. The high friction between the meteor and atmosphere causes it to extensively heat up. Most of the meteors due to heat shine brightly and quickly dissipate. However, some meteors are very large and they reach the Earth before they fully dissipate. A meteorite is the remaining meteor that lands on the Earth’s surface and it is generally very big and covers a large surrounding area.

Question 13. Perform an activity to show that a pole star can be located with the help of Ursa Major.

Answer 13. This activity must be performed on a clear night with no moon during summer at about 9:00 pm.

• Look towards the north of the sky and identify Ursa Major.
• Look at the two stars at the Ursa Major end.
• Imagine a straight line such that it passes through these two stars.
• Extend this imaginary line in the north direction.
• This line leads to a star which appears to be shining brighter. This is known as the Pole Star

Question 14. What is a solar system? Explain the characteristics of any two planets in the solar system.

Answer 14. The sun, planets and moons orbiting these planets, asteroids, meteoroids, comets, and other dwarf planets together make up the solar system. There are a total of eight planets revolving around the sun. They are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune which revolve in that order. Between Mars and Jupiter, an asteroid belt is found. All the planets move around the sun in an elliptical orbit.

Characteristics of Earth-

• It is the third planet of the solar system.
• Earth is also known as a blue planet due to the vast presence of water.
• It rotates around its axis for 24 hours.
• It revolves around the sun for a total of 365 days and 6 hours.
• It has one natural satellite called the moon.

Characteristics of Mars-

• It is the fourth planet of the solar system.
• Due to the red dust on Mars, it is also known as the red planet.
• Mars is much colder than earth.
• Diameter of Mars is approximately half of the earth’s diameter.
• Mars has two natural satellites. They are Phobos and Deimos.

Question 16. In which part of the sky will you find the planet venus if it is visible as an evening star?

Answer 16. The planet Venus is situated in the western part of the sky after sunset and is said to be known as an evening star.

Question 17. Name the largest planet in the solar system.

Answer 17. Jupiter is the largest planet in our solar system.

Question 18. What is a constellation? Name any two constellations.

Answer 18. The group of stars that forms an observable pattern in the sky is known as a constellation.

Two constellations are- Ursa Major and Orion.

Question 19. Name the two objects other than planets that are solar system members.

Answer 19. a) Meteors

Meteors are small celestial objects seen as bright lines of light in the sky. As the heat is generated due to the friction of the earth’s atmosphere, the Meteors are burnt out on entering. This causes the bright lines in the sky. They are not planets.

1. b) Asteroids- Asteroids are a collection of many small objects, gases and dust around the sun. Between the orbits of Mars and Jupiter, they occupy a large gap. These are not planets. They are celestial bodies and are known as Asteroids.

Question 20. Do all the stars found in the sky move? Explain.

Answer 20. No, the planet earth rotates on its axis from the west to the east. Therefore, all the stars (except the pole star) move from east to west. With reference to earth, the pole star in the sky does not seem to move because it is located above the axis of rotation of the earth in the north direction. It appears to be stationary in the sky.

Question 21. Why is the distance between stars calculated in light years? What do you understand by the sentence that a star is eight lightyears away from the earth?

Answer 21. The distance between the stars and the earth and the distance between the different stars is large. It is difficult to express this distance in kilometres (km). Therefore, these large distances are expressed in terms of light years. One lightyear equals the distance travelled by the light in one year. One lightyear is equal to 9.46 x 1012 km.

The distance of stars from the earth is eight lightyears. This means that the distance between them is equal to the distance travelled by the light in eight years, i.e. the distance of the star is 8 x (9.6 x 1012) = 7.6 x 1013 km away from earth.

Question 22. The radius of Jupiter is 11 times more than the radius of the earth. Calculate the ratio of the volumes of  Jupiter and the Earth. How many Earths can Jupiter accommodate?

Answer 22. Let’s consider Jupiter and Earth are two spheres with radii R and R,’ respectively. Given in the question that the radius of Jupiter is 11 times the radius of the earth.

So, R’= 11R

The volume of a sphere of radius r is given as = 4⁄3πr3

The volume of Earth = 4⁄3πr3

And the volume of Jupiter = π(R1)3 = 4⁄3 π(R1)3=1331[4/3πR3]

The ratio of the volume of Jupiter and Earth = volume of Jupiter volume of Earth =1331(4/3πR3)4/3πR3=1331

Therefore, this ratio suggests that  Jupiter can fit 1331 Earths in it.

Question 23. Morning star is the name given to

(a) pole star

(b) star Sirius

(c) planet Jupiter

(d) planet Venus

Answer 23. The answer is (d) planet Venus.

Explanation:

Planet Venus is more dazzling than any other star and is visible in the eastern sky before sunrise.

Question 24. Do stars emit light only during the night?

Answer 24. Stars emit light always but cannot be seen  during the day because of the excessive brightness of the sun.

Question 25. Paheli and Boojho observed 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?

Answer 25. Boojho is right because only planets cannot twinkle, whereas stars emit light from a far distance, and they twinkle.

Question 26. A star is ten lightyears away from the earth. Suppose it gets brightened up suddenly today. After how much time will we see this change?

Answer 26. We will see the change after ten years.

Question 27. Meteors are not visible during the daytime. Explain.

Answer 27. Meteors are not visible during the day because the brightness of a meteor is extremely small compared to that of the Sun.

Question 28. Does the moon change its shape daily?

Answer 28. We can only see that part of the moon from which the sun’s light is reflected towards us. Hence the moon changes its shape daily.

Question 29. Suppose the distance between the earth and the sun becomes half of its present distance. What is likely to happen to life?

Answer 29. Life may not exist because some special environmental conditions are needed to live and continue on the Earth. The right distance of the Earth from the sun is necessary to have the right temperature range, the presence of water, a suitable atmosphere, and a blanket of the ozone layer.

Question 30. Which characteristics of Mars separate it from other planets?

Answer 30. Mars appears slightly reddish and is also known as the red planet. It has two natural satellites.

Question 31. Which planet’s characteristic does Saturn make it unique in the Solar System?

Answer 31. Saturn has rings that differentiate it from the rest of the Solar System.

Question 32. Do all the stars that appear in the sky move? Explain.

Answer 32. Due to the earth’s motion, stars appear to move in the sky. Earth is spinning on its axis and moves around the sun. Some stars, like the pole star, do not appear to move because it is located in the direction of the earth’s axis.

Benefits of solving Important Questions Class 8 Science Chapter 17-

Science is an essential foundational subject in Classes 6, 7 and 8 for students planning to pursue careers in Science. . A lot of practice and consistent effort should go towards understanding the core concepts of Science. Going through our question bank of Important Questions Class 8 Science Chapter 17 will help students build a strong base of the chapter- Stars and The Solar System

Here are some benefits students can have  while revising the Important Questions Class 8 Science Chapter 17:

• Students will get all the exam-oriented questions from this chapter at  one place. This list would include questions from NCERT books, past years’ question papers, and other reference books that provide a complete revision of the entire chapter.
• The solutions are designed by Extramarks in-house  Science subject experts who have been teaching Science for many years. These solutions are based on the latest CBSE curriculum and strictly adheres to all the NCERT guidelines. So students can rely on our solutions completely. . Our team has given step-wise solutions that help students revise critical theoretical concepts to clear their doubts to solve specific problems.
• The list of  Important Questions Class 8 Science Chapter 17 includes a comprehensive list of questions from the entire chapter, making sure that solving them helps with the revision of the whole chapter.They improve their knowledge and understanding considerably to get a high score.

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