1. Who invented Stethoscope ?

Answer: Laennec of French in 1819.

2. Who invented Laser ?

Answer:

Charles H. Townes

3. Who invented Refrigerator ?

Answer:

Oliver Evans in 1805

4. Who invented Neutron bomb ?

Answer:

Samuel T. Cohen

5. Who invented Vitamin K ?

Answer: Doisy Dam of U.S.A. in 1938.

6. Who invented Steam Engine (Piston)

Answer: Thomas Newcomen of Britain in 1712

7. Who invented Ballistic missile ?

Answer: Wemher von Braun of Germany in 1944.