1. Who invented Transistor ?

Answer: Bardeen, Shockley & Britain of U.S.A. in 1948

2. Who invented Vitamin K ?

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

3. Who invented Open Heart Surgery ?

Answer:

Dr. Daniel Hale Williams

4. Who invented by Electric Lamp ?

Answer: Thomas Alva Edison of U.S.A. in 1879

5. Who invented watch ?

Answer:

Peter Henlein invented the first portable time piece in 1504

6. Who invented Refrigerator ?

Answer:

Oliver Evans in 1805

7. Who invented Hydrogen bomb ?

Answer:

Edward Teller