4. How many main Tropical cyclone warning centers are there in the world?
- 5
- 8
- 7
- 6
16
16. In which year Industrial Licensing was introduced in India?
- 1950
- 1951
- 1955
- 1965
62
20. What is the minimum distance (in metres) required to hear an echo?
- 17
- 13
- 15
- 21
77