1. Who invented Safety Pin ?

Answer: Walter Hunt of U.S.A. in 1849

2. Who invented watch ?

Answer:

Peter Henlein invented the first portable time piece in 1504

3. Who invented Stainless Steel ?

Answer: Harry Brearley of Britain in 1913.

4. Who invented Steam Engine (Condenser)

Answer: James Watt of Britain in 1765

5. Who invented Refrigerator ?

Answer:

Oliver Evans in 1805

6. Who invented by Electric Lamp ?

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

7. Who invented Relativity Theory ?

Answer: Einstein of Germany in 1905.