1. Who invented Steam Engine (Condenser)

Answer: James Watt of Britain in 1765

2. Who invented Electron ?

Answer: Thomson. J of Britain in 1897

3. Who invented Helicopter ?

Answer:

Igor Sikorsky

4. Who invented Submarine ?

Answer:

John Philip Holland

5. Who invented Vitamin A ?

Answer: Mc Collum and M.Davis of U.S.A. in 1913

6. Who invented Ballistic missile ?

Answer: Wemher von Braun of Germany in 1944.

7. Who invented Atomic Bomb ?

Answer: J. Robert Oppenheimer of U.S.A. in 1945