Exercise - Question:
Q1. Answer the following questions briefly :
(a) How does a planet differ from a star ?
Ans.
|
Stars |
Planets |
|
- stars emit a large amount of heat and light.
- they are big heavenly bodies.
- there are many stars which we cannot see with our naked eyes. |
- they do not have heat and light of their own. They only reflect the light of the sun - planets are called 'wanderers' because they revolve around the sun in their fixed orbits. - planets can be seen with the help of the telescope. |
(b) What is meant by the 'solar system' ?
Ans. The sun, the planets and satellites together with other minor bodies make up the solar system. The Sun is at the centre of the solar system. The planets revolve around the Sun in their fixed orbits. The satellites revolve around the planets.
(c) Name all the planets according to their distance from the Sun.
Ans. The planets according to their distance from the Sun are :
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto.
(d) Why is the earth called a unique planet ?
Ans. Earth is called a unique planet because
(i) Conditions favourable to support life are found only on the earth; it is neither too hot nor too cold.
(ii) Earth has surface water, which is very necessary for our survival.
(iii) It has life giving oxygen and the ozone layer, which protect us from the harmful rays of the sun.
(e) Why do we see only one side of the Moon always ?
Ans. The moon revolves round the earth in about 27 days. It takes exactly the same time to rotate on its axis. To complete both the movements, the Moon takes the same time. This is the reason why we see only one side of the Moon.
(f) What is the universe ?
Ans. The universe is the whole body of stars, planets, satellites and gases. It is endless. Stars are huge bodies of glowing gases e.g. sun. Planets and satellites do not have heat and light of their own, they are lit by the light of the stars.
Q2. Tick the correct answer -
(a) The planet know as the "Earth is twin" is.......
(i) Jupiter (ii) Saturn (iii) Venus
(b) Which is the third nearest planet to the Sun.......
(i) Venus (ii) Earth (iii) Mercury
(c) All the planets move around the Sun in a........
(i) Circular path (ii) Rectangular path (iii) Elliptical path
(d) Asteroids are found between the orbits of.......
(i) Saturn and Jupiter
(ii) Mars and Jupiter
(iii) The Earth and Mars
Ans. (a) (iii), (b) (ii), (c) (iii), (d) (ii), (e) (ii).
Q3. Fill in the blanks:
(a) A group of .......forming various patterns is called a.........
(b) A huge system of stars is called ........
(c) ..........is closest celestial body to our Earth .
(d) ........ is the third nearest planet to the Sun.
(e) Planets do not have their own ......... and ..........
Ans. (a) stars/constellation, (b) galaxy, (c) Moon, (d) Earth, (e) heat/light.
