Pressure
Pressure is the amount of force exerted per area.
Measuring pressure
1)Mercury barometer
The pressure at beneath a liquid surface (and therefore at the base of the mercury column) can be calculated with the following formula:
Pressure beneath liquid surface = ρgh
[ρ = density (kg/m3), g = acceleration due to gravity (10 m/s2), h = depth (m)]
2) Manometer
Pressure due to gas = atm + ρgh
[ρ = density (kg/m3), g = acceleration due to gravity (10 m/s2), h = depth (m)]
[atm = atmospheric pressure]