Ans Area of the sun covered by the moon
12. The instrument used to measure the specific gravity of milk is?
13. The internal antenna of transistor set is made of ?
Ans Ferror Chrome
14. Gerontology is the study of ?
Ans Process of ageing
15. Helium is used for respiration in deep water instead of nitrogen because
Ans It is heavier than nitrogen
16. In a fluorescent tube which of the following components are found?
Ans Mercury vapour
17. The common ore of aluminium is ?
18. When one enters a dark room, he is not able to see anything but, after sometime vision improves. This is because ?
Ans The pupil ofthe eye dilates
19. Radio carbon dating is used to find the age of ?
20. What is periscope used for ?
Ans To survey the ships on the surface of the sea when the submarine is under water