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

2. The density of water is greatest at:

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

4. The of light in vacuum is about

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

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

7. The unit of home electricity energy consumption is:

8. Which one of the following statements is true:

9. An eclipse of the sun occurs when

10. The most abundant natural Iron oxides are

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

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

13. Sun is a:

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

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

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

17. An electric current can produce

18. The age of the solar system is

19. The most abundant in sea water are

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