Question

Draw the diagram of mercury barometer.

Answer 1

Hint
The basic construction of the mercury barometer is that it consists of a long tube of certain length, a reservoir to store the mercury and the required amount of mercury. This setup is not changed from Torricelli's experiment . It is called a glass manometer filled with mercury.

Complete step by step solution
A Barometer is an estimating apparatus which is used to measure the atmospheric pressure. It is particularly used in weather forecasting and to discover the altitude.
Construction mercury barometer:
A mercury Barometer otherwise known as the Torricellian barometer is made up of an upside-down long glass tube of length three feet which is closed at one of the ends and the open end is made to stand in the glass reservoir filled with mercury.

Working of mercury barometer:
When the glass tube is immersed in the mercury the air pressure in the atmosphere presses the surface of the mercury. This causes some of the mercury in the tube to rise up inside the tube. The mercury inside the tube rises if the air pressure in the atmosphere is greater. We can read the pressure of the atmosphere from the readings marked in the glass tube. When there is less atmospheric pressure the rise of mercury in the tube is less.

Note
While drawing the mercury barometer or Torricellian barometer the marking of the atmospheric pressure that acts on the surface of the mercury and the vacuum that is present inside the glass tube is extremely very important. The chemical symbol of mercury is $Hg$ .