11. The purest form of water is obtained from
Ans Heavy rains
Ans Heavy rains
12. Diamond and Emerald contain
Ans Carbon and silicon
13. Cloudy nights are warmer than clear nights due to
Ans Prevention of heat radiated out by the earth from escaping into the sky
14. Which of the following semi-conductor ?
Ans Copper
15. As one climbs up the Mount Everest, one experiences difficulty in breathing due to
a. Low content of nitrogen
b. Low content of oxygen
c. High content of carbon dioxide
Ans None of above
16. A camera forms
Ans Real but inverted images
17. The gas used in Soda water is
Ans Carbon dioxide
18. A red flower placed in green light appears
Ans black
19. The metal used in storage batteries is
Ans Lead
20. A instrument used to detect the presence of a current in a circuit is called
Ans Ammeter