Stars And The Solar System
Class 8th Science CBSE Solution
- Which of the following is NOT a member of the solar system? (a) An asteroid (b) A…
- Which of the following is NOT a planet of the sun? (a) Sirius (b) Mercury (c) Saturn (d)…
- Phases of the moon occur because (a) we can see only that part of the moon which reflects…
- Fill in the blanks: (a) The planet which is farthest from the sun is ___________. (b) The…
- Mark the following statement as true (T) or false (F). (a) Pole star is a member of the…
- Match items in column A with one or more items in column B. A B (i) Inner planets (a)…
- In which part of the sky can you find Venus if it is visible as an evening star?…
- Name the largest planet of the solar system.
- What is a constellation? Name any two constellations.
- Draw sketches to show the relative position of prominent stars in (a) Ursa Major and (b)…
- Name two objects other than planets which are members of the solar system.…
- Explain how you can locate the Pole Star with the help of Ursa Major.…
- Do all the stars in the sky move? Explain.
- Why is the distance between stars expressed in light years? What do you understand by the…
- The radius of Jupiter is 11 times the radius of the Earth. Calculate the ratio of the…
- Boojho made the following sketch (Fig. 17.29) of the solar system. Is the sketch correct?…
Exercises
Question 1.Which of the following is NOT a member of the solar system?
(a) An asteroid
(b) A satellite
(c) A constellation
(d) A comet
Answer:
The correct option is (c) A constellation
Question 2.
Which of the following is NOT a planet of the sun?
(a) Sirius
(b) Mercury
(c) Saturn
(d) Earth
Answer:
The correct option is (a) Sirius
Question 3.
Phases of the moon occur because
(a) we can see only that part of the moon which reflects light towards us.
(b) our distance from the moon keeps changing.
(c) the shadow of the Earth covers only a part of the moon's surface.
(d) the thickness of the moon's atmosphere is not constant.
Answer:
The correct option is (a) we can see only that part of the moon which reflects light towards us.
Question 4.
Fill in the blanks:
(a) The planet which is farthest from the sun is ___________.
(b) The planet which appears reddish in colour is___________.
(c) A group of stars that appear to form a pattern in the sky is known as a ___________.
(d) A celestial body that revolves around a planet is known as a ___________.
(e) Shooting stars are actually not ___________.
(f) Asteroids are found between the orbits of ___________ and ___________.
Answer:
(a) The planet which is farthest from the sun is Neptune.
(b) The planet which appears reddish in colour is Mars.
(c) A group of stars that appear to form a pattern in the sky is known as a constellation.
(d) A celestial body that revolves around a planet is known as a satellite.
(e) Shooting stars are actually not stars.
(f) Asteroids are found between the orbits of Mars and Jupiter.
Question 5.
Mark the following statement as true (T) or false (F).
(a) Pole star is a member of the solar system. ( )
(b) Mercury is the smallest planet of the solar system. ( )
(c) Uranus is the farthest planet in the solar system. ( )
(d) INSAT is an artificial satellite. ( )
(e) There are nine planets in the solar system. ( )
(f) Constellation Orion can be seen only with a telescope. ( )
Answer:
(a) False
(b) True
(c) False
(d) True
(e) False
(f) False
Question 6.
Match items in column A with one or more items in column B.
Answer:
Question 7.
In which part of the sky can you find Venus if it is visible as an evening star?
Answer:
Venus appears in the western sky after sunset and is called the evening star.
Question 8.
Name the largest planet of the solar system.
Answer:
Jupiter is the largest planet of the solar system.
Question 9.
What is a constellation? Name any two constellations.
Answer:
A constellation is a group of stars that forms a recognizable pattern in the sky. The two constellations name are Ursa Major and Orion.
Question 10.
Draw sketches to show the relative position of prominent stars in (a) Ursa Major and (b) Orion.
Answer:
(a) Ursa Major appears like a big dipper. There are three bright stars in the handle and four stars in the bowl of the dipper as shown in below figure.
(b) Orion appears like a hunter. Three bright stars appear in the belt, while five bright stars are arranged in the form of a quadrilateral as shown in the below figure.
Question 11.
Name two objects other than planets which are members of the solar system.
Answer:
Asteroids and Meteors are objects other than planets which are members of the solar system.
Question 12.
Explain how you can locate the Pole Star with the help of Ursa Major.
Answer:
The pole star can be located using the Ursa Major constellation, by imagining a line towards the Northern direction connecting two stars present at the end of the bowl, This imaginary line meets Pole Star. The length of the imaginary line from the bowl is about five times the distance between the two stars of the bowl.
Question 13.
Do all the stars in the sky move? Explain.
Answer:
No, Stars do not move in the sky. They actually appear to move from east to west due to rotation of earth on its axis from west to east.
Question 14.
Why is the distance between stars expressed in light years? What do you understand by the statement that a star is eight light years away from the Earth?
Answer:
The distance of the stars from the Earth and the distance between the stars are very large. Therefore, we can’t express these distances in kilometer (km). Thus, these large distances are expressed in another big unit called light years.
One light year is the distance travelled by light in one year.
1 light year = 9.46 x 1012 km.
A star is located eight light years away from the Earth. This means that the distance between the star and the Earth is equivalent to the distance travelled by light in eight years, i.e., a star is located 8 x (9.46 x 
) = 7.6 x 
km away from the Earth.
Question 15.
The radius of Jupiter is 11 times the radius of the Earth. Calculate the ratio of the volumes of Jupiter and the Earth. How many Earths can Jupiter accommodate?
Answer:
Earth and Jupiter can be considered as two spheres with radii r and r' respectively. Given that the radius of Jupiter is 11 times the radius of the Earth.
Thus, r' = 11 r
Thus, the jupiter can accommodate 1331 earth in it.
Question 16.
Boojho made the following sketch (Fig. 17.29) of the solar system. Is the sketch correct? If not, correct it.
Answer:
No, the sketch is not correct because the positions of planets Mars and Venus are interchanged. And the positions of Uranus and Neptune are interchanged. Also, the Asteroid belt is shown in the gap between the orbits of Jupiter and Saturn which is not correct. The asteroid belt is located between the orbits of Mars and Jupiter. The correct fig is given below.
