Question

The empty space above the mercury in a simple barometer is called __________ vacuum.
A) Pressure
B) Barometric
C) Torricellian
D) Mercuric

Answer 1

Hint: The tool used to measure the atmospheric pressure is called a barometer. The barometer is filled with mercury. The top of the barometer is filled with the vacuum because the mercury must have enough space to expand and contract without the other force acting on it. A vacuum filled with fluid, such as mercury in which one end is closed, then we can say the vacuum as a Torricellian vacuum. Use this concept to answer the question.

Complete step by step solution:
A barometer stabilizes the mercury level in the glass tube that is sealed with the atmospheric pressure on the open mercury chamber. The top part of the barometer is filled with the vacuum because the vacuum must have enough space to expand and contract without any external force acting on it.

If gas is present in the top part of the barometer then that gas will exert a force against the mercury and gives inaccurate readings. Reading in the barometer is also adjusted for temperature. Low atmospheric pressure allows the mercury to drop and high atmospheric pressure pushes the mercury up. The height of the mercury column is highest when there is a greater atmospheric pressure.

Space is called a vacuum. It was first explained by a scientist Torricelli. That space is called the Torricelli vacuum. A vacuum filled with fluid, such as mercury in which one end is closed, then we can say the vacuum as a Torricellian vacuum. The vacuum is filled with fluid in a tube with one end closed and when immersing the other end in the vessel of the same fluid, then the fluid will descend till it is counterbalanced by the pressure of the atmosphere.
Hence the vacuum is called Torricelli vacuum.

Hence option $\left( C \right)$ is the right option.

Note: Torricelli the scientist is the first one to explain the phenomena, hence the empty space is called Torricelli vacuum. The tool used to measure the atmospheric pressure is called a barometer. The barometer is filled with mercury. Reading in the barometer is also adjusted for temperature. The height of the mercury column is highest when there is a greater atmospheric pressure.