Atmospheric pressure is measured by

Answer: Option B

Explanation:

newton second is unit of impulse,

watt is unit of Power,

newton per meter is unit of Surface Tension.

Answer: Option C

Explanation:

Cathetometer - is used to determine heights,

Chronometer - is used to longitude of a vessel at sea,

Commutator - is used to convert AC to DC.

Answer: Option B

Answer: Option A

Explanation:

K. Macmillan of Scotland invented Bicycle in 1839.

Barometer was invented by E. Torricelli of Italy in 1644.

Calculating Machine was invented by Pascal of France in 1642.

Centigrade Scale was invented by A. Celsius of France in 1742.

Answer: Option D

Explanation:

Red, Green, Blue are primary colours. All the colours can be produced by them by mixing in different proportions. Interesting :)