Question 1. From the following pick out, which is not the member of the solar system?
(a) A satellite
(b) A comet
(c) An asteroid
(d) A constellation
Solution : (d) A constellation
A constellation is not the member of the solar system. These are the group of stars that forms a recognizable shape is known as Constellation.
Question 2. Which is not a planet of the sun from the following?
(a) Mercury
(b) Earth
(c) Sirius
(d) Saturn
Solution : (c) Sirius
It is not the planet of the sun but it is a star.
Question 3. What is the reason behind the phases of the moon?
a) Continuous changing of the distance of the moon from us
b) The thickness of the moon’s atmosphere is variable
c) We can see only that part of the moon which reflects light towards us.
d) Only the part of the moon’s surface is covered by the Earth’s shadow
Solution : (c) We can see only that part – of the moon, which reflects light towards us.
Moon does not have its own light. It is only be seen by us when sunlight falls on the moon and gets reflected towards us. So, we can only see the part of the moon on which the sunlight falls and reflects towards us.
Question 4. Complete the following sentences :
(a) Farthest planet from the sun is _________.
(b) ________ are not actually shooting stars.
(c) The planet whose color is red is _______.
(d) ________ are the celestial body that revolves around the planet.
(e) ________ are the group of stars that appears to form a pattern in the sky.
(f) Asteroids are found between the orbits of _______ and _____.
Solution :
(a) Farthest planet from the sun is Neptune.
(b) Shooting stars are not actually stars.
(c) The planet whose color is red is Mars.
(d) Satellites are the celestial body that revolves around the planet.
(e) Constellation is the group of stars that appears to form a pattern in the sky.
(f) Asteroids are found between the orbits of Mars and Jupiter.
Question 5. Mark the following statements 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 the artificial satellite. ( )
(e) There are nine planets in the solar system. ( )
(f) Constellation Orion can be seen only with a telescope. ( )
Solution :
(a) (F)
(b) (T)
(c) (F)
(d) (T)
(e) (F)
(f) (F)
Question 6. Match items in column A with one or more items in column B.
| A | B |
| (i) Inner planets | (a) Saturn |
| (ii) Outer planets | (b) Great Bear |
| (iii) Constellation | (c) Moon |
| (iv) Satellite of the Earth | (d) Mars |
Solution :
(i) (d)
(ii) (a)
(iii) (b)
(iv) (c)
Question 7. In which part of the sky can you find Venus if it is visible as an evening star?
Solution : Venus appears in the western sky just after sunset.
Question 8. Which planet is largest in the solar system?
Solution : Jupiter is the largest planet in the solar system.
Question 9. What do you mean by constellation? Name any two.
Solution : The group of stars that forms a recognizable pattern in the sky is known as constellation.
Two constellations are;
Question 10. Draw sketches to show the relative positions of prominent stars in
(a) Ursa Major and
(b) Orion.
Solution :
Question 11. Name two objects other than planets which are members of the solar system.
Solution : Satellites and asteroids are the objects that are the members of solar system.
Question 12. Explain how you can locate the pole star with the help of ursa major.
Solution : To find the location of pole star with the help of ursa major, consider the two stars at the end of the bowl of ursa major. Now, draw an imaginary straight line in northern direction connecting these two stars. The imaginary line would meet a star known as pole star. The distance of pole star is around five times away from the bowl.
Question 13. Do all the stars in the sky move? Explain.
Solution : No,all the stars do not move. The movement of all stars in the sky is from east to west except pole star. With respect to earth, the pole star looks stationary because it is located above the axis of rotation of the earth in the north direction.
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?
Solution : The distance in-between stars and between earth and stars are in range of millions of kilometres. So, these distances cannot be expressed in kilometres; hence, distance between stars is expressed in light years.
One light year is the distance travelled by light in one year. One light year is equal to 9.46 × 1012 km.
A star located at eight light years away from earth means that the distance between the star and the earth is equal to the distance travelled by light in years. In figures, eight light years will be equal to 8 x 9.46 × 1012 km = 7.6 × 1013 km.
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 accomodate?
Solution : Given that the radius of jupiter is 11 times the radius of the earth. Suppose the radius of earth be r, then the radius of the jupiter will be 11r.
Therefore, ratio of volumes of jupiter and earth = (volume of jupiter)/(volume of earth)
= (4/3 π (11r3))/ (4/3 π (r3))
= 1331/1
= 1331:1
Hence, jupiter can accommodate 1331 number of earths.
Question 16. Boojho made the following sketch (fig.) Of the solar system. Is the sketch correct? If not, correct it.
Solution : The sketch made by boojho is not correct because the position of mars, venus, uranus and neptune are wrong. The position of mars & venus and uranus & neptune should be interchanged. The correct sketch is as shown below: