Question

To measure atmospheric pressure, Torricelli in 1643 made an instrument, which is called:
A. Hygrometer
B. Barometer
C. Anemometer
D. None of these

Answer 1

Torricelli was an Italian mathematician and physicist. He was a student of Galileo. Evangelista Torricelli's work headed to initial thoughts about atmospheric pressure. He used a mercury column for the measurement of pressure.

Complete step by step solution:
- In the question it is asked to find the instrument which was made by Torricelli in 1643.
- Torricelli in 1643 made an instrument to find the atmospheric pressure.
- The instrument made by Torricelli to measure atmospheric pressure is the Barometer.
- The barometer contains a mercury column of height of 76 cm to measure atmospheric pressure.
- Barometer is called a barometric pressure.
- Therefore, to measure atmospheric pressure, Torricelli in 1643 made an instrument, which is called a barometer.

So, the correct option is B.

Additional information:
- Torricelli is known for his discovery of the barometer and he is also known for his improvements in optics.
- The benefits of using mercury in a barometer are its density is very high and mercury has low vapor pressure.
- Mercury neither gets wets and nor sticks to glass.

Note: Working of a barometer is the same in indoor and outdoor also. It is going to measure ambient pressure. Barometer is used to measure height above sea level. Water is not going to be used in a barometer because of its low density. The unit which is used in barometers to measure pressure is millibar (mb).