The increase in pressure at a point in the enclosed liquid in equilibrium is transmitted equally in all directions in liquid and to the Walls of the container.
The working of hydraulic lift, hydraulic press and hydraulic brakes are based on Pascal’s law.
Atmospheric Pressure
The pressure exerted by the atmosphere on earth is atmospheric pressure. It is about 100000 N/m2
It is equivalent to a weight of 10 tones on 1 m2.
At sea level, atmospheric pressure is equal to 76 cm of mercury column. Then, atmospheric pressure
= hdg = 76 x 13.6 x 980 dyne/cm2
[The atmospheric pressure does not crush our body because the pressure of the blood flowing through our circulatory system] balanced this pressure.]
Atmospheric pressure is also measured in torr and bar.
1 torr = 1 mm of mercury column
1 bar = l05 Pa
Aneroid barometer is used to measure atmospheric pressure.
