Answer:
A mercury barometer is a device use to measure stomspheric pressure and is constructed as following:
- A mercury barometer requires a tube which has one close end, and one open end.
- Tube is placed upside down in a beaker in such a way so that one end open in the beaker and the other remain outside of the beaker.
- The barometric liquid (mercury) is then filled in the tube by pouring mercury liquid in the beaker.
The position of tube creates vacuum between the closed end of the tube and liquid surface and the Mercury has high density that is why used as the liquid to measure pressure.