Question

Practical fluids used in manometer at different pressures

Answer 1

Following are the reasons why mercury and not water is used in a barometer:

Mercury is relatively denser than water, consequently the length of the column of water would have to be about 34 feethigh to exert pressure equal to that of the atmosphere while the column of mercury need to be only 30 inches to exert pressure equal to that of the atmosphere.Mercury has a very low vapor pressure when compared to that of water. So it is more sensitive than water to the changes in the atmospheric pressure and rises more quickly to record the changes in the atmospheric pressure.Mercury's freezing point is much lower than that of water's so it can record the atmospheric pressure at temperatures below that of 0 degrees centigrade.Mercury does not evaporate easily so very little mercury vapor enters the vacuum above the mercury in the tube.Mercury being a metal shines brightly and so can be used to read the markings on the tube easily.

Answer 2

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Use fluid pressure pressure are :-

• The force of Buoyancy, which pushes or helps the ship/boat to float on water.
• The use of Hydraulic force, used in lifting the vechiles in the repairing shops.
• The force which pushes the lid of the coke when applied some force on it.
• The mysterious force which comes out, when the Dam gates are open.
• The Turbines in Water, which are rotated through the force of water.