1. Which rocks are formed by the aliteration of pre-existing rocks by great heat or pressure?

2. Light from Sun travels a distance before it reaches Earth:

3. The speed of sound in dry air at 20C is about

4. unit of length equal to the average distance between the earth and sun is called

5. When sound is reflected from floor, ceiling or a wall, it mixes with the origial sound and change its complexion, it is called as

6. The planet of the solar system which has maximum numbers of Moon is:

7. The unit of home electricity energy consumption is:

8. An eclipse of the sun occurs when

9. The most abundant in sea water are

10. The ozone layer protects the earth from rays sent by the sun:

11. The magnet always points in the same direction, if move freely i.e. towards nort and south poles, because of:

12. The age of the solar system is

13. The of light in vacuum is about

14. Which one of the following statements is true:

15. The most suitable thermometer for measuring the boiling point of water is:

16. An electric current can produce

17. Sun is a:

18. The most abundant natural Iron oxides are

19. The time light takes from Sun to reach Earth is:

20. The density of water is greatest at: