CBSE Class 8 Science Chapter-17 Stars and Solar System Important Questions - Free PDF Download
Very Short Answer Questions: 1 Marks
1. Which one of the following is a star?
a. Sun
b. Moon
c. Earth
d. Venus
Ans: a. Sun
2. _______________ is a constellation which looks like a distorted letter W or M.
a. Orion
b. Great Bear
c. Cassiopeia
d. Leo major
Ans: c. Cassiopeia
3. Which one of the following is a natural satellite of the earth?
a. Venus
b. Mercury
c. Sun
d. Moon
Ans: d. Moon
4. Which one of the following statements is false about Uranus?
a. Uranus is the innermost planet of the solar system.
b. Uranus also rotates from east to west.
c. Uranus has a highly tilted rotation axis.
d. Uranus can be seen only with the help of large telescopes.
Ans: a. Uranus is the innermost planet of the solar system.
5. Artificial satellites are used for _________________.
a. weather forecasting
b. remote sensing
c. transmitting radio signals
d. all of these
Ans: d. All of these
6. __________ is the source of almost all energy on the Earth.
a. Satellites
b. Stars
c. Sun
d. Moon
Ans: c. Sun
7. The gap between the orbit of mars and Jupiter is ______________.
a. meteorite
b. meteor
c. asteroid
d. comet
Ans: c. asteroid
8. The study of celestial objects and associated phenomena is called ____________.
Ans: Astronomy.
9. After the full moon day, the sunlit part of the moon is visible from the Earth ___________ in size every day.
Ans: Decreases
10. Which is the brightest star in the sky?
Ans: Sirius
11. What is the distance of the Sun from the Earth?
Ans: 8 Light Minutes
12. Stars appear to move from ____________ to __________.
Ans: East to West
13. Define constellations.
Ans: The group/cluster of star forming a particular shape is called a constellation
14. _____________ is another prominent constellation in the northern sky.
Ans: Cassiopeia
15. What helped our ancestors to devise calendars and almanacs?
Ans: Passage of sun, star, planet and moon.
16. Name the planet which is denser than water.
Ans: Saturn
17. What is a satellite?
Ans: Any celestial body revolving around a plant is called its satellite.
18. It is convenient to express the distances of stars in _______________.
Ans: Light Years
19. _______________landed on the moon for the first time.
Ans: Neil Armstrong
20. Name the comet which appears after every 76 years?
Ans: Halley’s Comet.
21. Which planet is also known as Brihaspati?
Ans: Jupiter
22. Plant which takes the longest to go around the sun?
Ans: Neptune
Short Answer Questions: 3 Marks
23. Identify the constellations given below.
Ans: a. Great Bear b. Cassiopeia c. Orion
24. Write a short note on Ursa Major.
Ans: Ursa Major is one of the constellations seen in the night sky. It is also known as Big Dipper, The Great Bear or Saptarishi. This constellation consists of seven prominent stars. This constellation helps to locate the Pole star.
25. Why do you think phases of the moon are important in our social life?
Ans: The phases of the moon are significant in our social lives since most Indian festivals are held in accordance with the moon's phases. Diwali, for example, falls on the new moon day, whereas Budh Poornima and Guru Nanak's birthday fall on the full moon day. On the thirteenth night of the waning moon, Maha Shivratri is observed. Eid Ul-Fitr is celebrated on the day after the crescent moon is seen. Not just the festivals, many people in ayurveda relate the phases of the moon with human health.
26. Briefly describe the surface of the moon.
Ans: The moon's surface is dusty and barren. There are several craters of various sizes. There are several steep and high mountains in the area. Some of them are as tall as the world's highest mountains.
27. Define the following terms.
a. Orbit: A planet has a definite path in which it revolves around the Sun. This path is called an orbit.
b. Period of revolution: The time taken by a planet to complete one revolution is called its period of revolution.
28. Correct the following statements.
a. The moon has different layers of atmosphere and has no water.
Ans: The moon has no atmosphere as well as no water.
b. Stars do not emit light of their own.
Ans: Stars emit their own light and shine bright in the night sky.
29. Why does the pole star appear to be stationary from the Earth?
Ans: From every location on the planet, the pole stars appear to be stationary. This is due to the fact that it is located on a line parallel to the earth's axis of rotation. Pole star is located in the north. Hence when we see the pole star straight above us, and it appears to be stationary.
30. Write a short note on comets.
Ans: Comets are one of the members of our solar system. They have tremendously elliptic orbits around the Sun. Their time of revolution around the Sun, on the other hand, is usually quite long. A comet is characterised by a luminous head and a long tail. As it gets closer to the sun, the length of the tail lengthens. A comet's tail is always pointed away from the sun.
31. What do you know about ‘Mangalyaan’?
Ans: ISRO launched India's first interplanetary mission, Mangalyaan. After Roscosmos, NASA, and the European Space Agency, India became the first Asian country and the fourth in the world to reach the planet. On September 24, 2014, it was successfully deployed into a Mars orbit. With this, India became the first country in the world to accomplish this goal on its first try.
32. Give any four examples of artificial satellites.
Ans: Some of the Indian artificial satellites are as follows:
IRS-1B (1991)
INSAT-2DT (1992)
INSAT-2A (1992)
Mars Orbiter Mission (2013)
Chandrayaan-2 (2019)
33. Explain the arrangement of stars in the Orion constellation.
Ans: Orion is a well-known constellation that can be seen all throughout the world because it is placed on the celestial equator. It consists of seven bright stars. Hunter is another name for Orion. Three stars in the middle form a belt and four bright stars appear to be in a quadrilateral formation.
34. Write the names of eight planets in their order of distance from the Sun.
Ans: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.
35. What are asteroids, meteors and meteorites?
Ans:
Asteroids: A huge number of tiny objects that spin around the Sun occupy the space between Mars and Jupiter's orbits, which is known as the asteroid belt.
Meteors and Meteorites: A meteor is a tiny object that reaches the earth's atmosphere on rare occasions. It has a very fast speed at the time of entering the earth. The friction caused by the atmosphere causes it to heat up. It shines brightly and quickly dissipates. Some meteors are large enough to reach Earth before entirely dissipating. A meteorite is a body that lands on the Earth. It gives a large surrounding area.
Long Answer Questions: 5 Marks
36. Explain the phases of the Moon.
Ans: The full moon day is the day when the entire disc of the moon is visible. Every night following that, the size of the bright section of the moon appears to get smaller and smaller. The moon is not visible on the fifteenth day. The ‘new moon day' is celebrated on this day. The day after the new moon, only a small part of the moon is visible in the sky. This is known as the crescent moon. The moon slowly gets bigger every day. We obtain another full view of the moon on the fifteenth day. The various shapes of the bright part of the moon as seen during a month are called phases of the moon.
37. Sketch a simple diagram of positions of the moon in its orbit and its corresponding phases.
Ans:
38. Demonstrate an activity to show that a pole star can be located with the help of Ursa Major.
Ans: This activity should be performed on a clear moonless night during summer at about 9.00 pm.
Look towards the northern part of the sky and identify Ursa Major.
Look at the two stars at the end of Ursa Major.
Imagine a straight line passing through these stars.
Extend this imaginary line towards the north direction.
This line will lead to a star which is shining bright. This is the Pole Star
39. What is a solar system? Explain characteristics of any two planets in the solar system.
Ans: The Sun, eight planets and their moons, comets, asteroids, meteoroids, and dwarf planets make up a solar system, which revolves around it. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune are the eight planets that revolve around the Sun in given order. Between Mars and Jupiter, an asteroid belt exists. These planets revolve around the Sun in an elliptical orbit.
Characteristics of Earth:
It is the third planet in the solar system.
It is also known as a blue plant due to the presence of water.
It revolves around the sun for 365 days and 4 hours.
It rotates around its own axis in 24 hours.
It has one natural satellite known as the moon.
Characteristics of Mars:
It is the fourth planet in the solar system.
It is also known as the red planet due to the presence of red dust.
Mars is much colder than earth.
Its diameter is approximately half of earth’s diameter.
Mars has two natural satellites known as Phobos and Deimos.
Chapter Summary: Stars and The Solar System Chapter - 17 Class 8 Science
Explore the vast cosmos in this chapter as we unravel the mysteries of stars and our solar system. From understanding the lifecycle of stars to delving into the planets, moons, and asteroids that make up our solar neighborhood, this chapter provides a fascinating journey through space. Learn about the Sun's pivotal role, the Earth-Moon system, and the intriguing phenomena occurring in the celestial sphere. The chapter not only illuminates the science behind these cosmic entities but also sparks curiosity about the wonders of the universe.
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Unlock the wonders of the universe with Vedantu's Important Questions for Class 8 Chapter 17 Science - 'Stars and the Solar System.' Explore the benefits of these curated questions to enhance your understanding and excel in your science journey.
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Conclusion
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FAQs on Important Questions for CBSE Class 8 Science Chapter 17 - Stars and The Solar System
1. From an exam perspective for the 2025-26 session, what is the fundamental difference between a star and a planet?
This is a frequently asked question in exams. The main differences are:
- Light Source: Stars, like our Sun, are celestial bodies that produce their own heat and light. Planets do not have their own light; they only reflect the light from a star they orbit.
- Motion: Planets revolve around a star in a fixed path called an orbit. Stars are not stationary but are so far away that their movement relative to each other is not easily noticeable. They appear to move across the sky due to the Earth's rotation.
- Nature: Stars are massive, hot balls of gas. Planets are much smaller bodies that can be rocky (like Earth) or gaseous (like Jupiter).
2. How can we locate the Pole Star in the night sky using a constellation?
The Pole Star (or Dhruva Tara) can be located using the Ursa Major constellation, also known as the Saptarishi or The Great Bear. To find it, first, identify the seven prominent stars forming a shape like a large ladle or question mark. Imagine a straight line connecting the two stars at the end of the ladle's bowl. If you extend this imaginary line northwards, it will point directly to a bright star that isn't moving. This is the Pole Star.
3. Why does the Pole Star appear to be stationary from any point on Earth?
The Pole Star appears to be fixed in the sky because it is situated very close to the Earth's axis of rotation, extended into space. As the Earth spins on its axis, all other stars seem to circle around this point. Since the Pole Star lies on this axis, it remains in the same position from our perspective, making it a reliable indicator of the north direction.
4. List the eight planets of our solar system in their correct order from the Sun.
For the CBSE Class 8 exam, it is crucial to know the correct order of the planets. Starting from the one closest to the Sun, they are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
5. What are the phases of the moon and what causes them?
The different shapes of the bright part of the moon that we see over a month are called the phases of the moon. This phenomenon occurs for two reasons:
- The Moon does not produce its own light; it shines because it reflects sunlight.
- The Moon is constantly revolving around the Earth.
6. For a 3-mark question, how would you differentiate between an asteroid, a comet, and a meteor?
Here is a clear differentiation for scoring full marks:
- Asteroids: These are large, rocky celestial bodies that orbit the Sun. A large number of them are found in the asteroid belt, a region located between the orbits of Mars and Jupiter.
- Comets: These are lumps of ice, rock, and dust that orbit the Sun in highly elliptical paths. When a comet approaches the Sun, the ice turns into gas, forming a glowing head and a long tail that always points away from the Sun. Halley's Comet is a famous example.
- Meteors: Often called 'shooting stars', meteors are small pieces of rock or dust that burn up due to friction upon entering Earth's atmosphere, creating a bright streak of light. If a piece survives and lands on Earth, it is called a meteorite.
7. What makes Earth a unique planet capable of supporting life?
Earth's ability to support life is due to several critical factors, making it an important topic:
- Ideal Distance from the Sun: This allows for a moderate temperature range where water can exist as a liquid, which is essential for life.
- Presence of an Atmosphere: The atmosphere contains essential gases like oxygen for respiration and protects us by burning up most meteors.
- The Ozone Layer: A layer within our atmosphere that shields the surface from the Sun's harmful ultraviolet (UV) radiation.
- Abundance of Water: The presence of water in liquid form is crucial for all biological processes.
8. What are artificial satellites and what are their most important uses?
Artificial satellites are human-made objects that are launched into space to orbit the Earth or other celestial bodies. They are different from natural satellites like the Moon. Their important uses include:
- Communication: Transmitting television, internet, and telephone signals globally.
- Weather Forecasting: Observing cloud patterns and weather systems to predict weather.
- Remote Sensing: Monitoring Earth's geography, agriculture, and natural resources.
- Navigation: Providing precise location data for Global Positioning Systems (GPS).
9. Name the largest planet in our solar system and the planet known as the 'Red Planet'.
The largest planet in our solar system is Jupiter. The planet known as the 'Red Planet' is Mars, which gets its reddish colour from the iron oxide (rust) on its surface. These are common one-mark questions in exams.
10. What is a light-year and why is this unit necessary in astronomy?
A light-year is the distance that light travels in one full year. It is a unit of distance, not time. This unit is necessary because the distances between stars and galaxies are immense. Using kilometres or miles would result in incredibly large and impractical numbers. The light-year provides a more convenient and manageable scale for expressing these vast cosmic distances.
11. Why can't we see the stars during the daytime?
Stars are always in the sky, but we can't see them during the day. This is because our own star, the Sun, is much closer to us and its light is extremely bright. The Sun's light scatters throughout the Earth's atmosphere, making the sky so luminous that it overpowers the faint light coming from distant stars, rendering them invisible to our eyes.
12. Describe the key features of the Orion constellation.
Orion, also known as 'The Hunter', is one of the most magnificent constellations in the night sky. Its key features are:
- It has seven or eight very bright stars.
- Three stars in the middle are aligned in a straight line, forming the 'belt' of the hunter.
- Four other bright stars appear to form a quadrilateral, outlining the hunter's body.
- The brightest star in the entire night sky, Sirius, can be located by extending the line of Orion's belt eastwards.
13. What was India's 'Mangalyaan' mission and why is it considered a significant achievement?
Mangalyaan, also known as the Mars Orbiter Mission (MOM), was India's first mission to another planet. Launched by the Indian Space Research Organisation (ISRO), it successfully entered Mars' orbit on September 24, 2014. It is a significant achievement because India became the first nation in the world to successfully reach Mars on its very first attempt, showcasing its advanced and cost-effective space technology.
14. Which planet is famous for its rings, and what are these rings made of?
Saturn is the planet renowned for its spectacular system of rings. These rings are not solid bands but are composed of billions of small particles of ice, rock, and dust, all orbiting the planet at different speeds. Although other gas giants like Jupiter also have rings, Saturn's are the largest and most easily visible from Earth.
