Question

why mercury is used as barometric liquid????????????
(minimum 2 reasons)

Answer 1

the main two reasons are
1. Due to its high specific weight or relative density ( reduces the length of mercury column)
2. Due to its less value of vapour pressure (negligible error in actual pressure measurements)

Answer 2

Advantages of using Mercury as a barometric liquid are:-

• The density of Mercury (=13.6 × 10³ kg/m³) is greater than that of any other liquid, so only 0.76 m height of Mercury column is needed to balance the normal atmospheric pressure. Use of other liquids require much longer tube.
• The vapour pressure of mercury is negligible so the vapours in the torricellian vacuum does not affect the barometric height.

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