The percentage of oxygen present in air is approximately-
A). 44%
B). 23%
C). 40%
D). 21%
1. An example of replenshible energy source is
2. Which one of the following is extensively used for sterilizing water ?
3. Soap is a mixture of sodium or potassium salts of
5. Afferent nerve fiber carries impulses from
6. What should a person on a freely rotating turn table do to decrease his (angular) speed ?
7. The layer of atmosphere used for radio wave transmission is
8. What happens to a liquid when the vapour pressure equals the atmospheric pressure?