TBR: 760 mm Hg Clarification

[justadream]

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TBR GC Book II page 36



“Every 760mm Hg of height in a mercury column exerts a gravitational force that when applied over a unit area equals 1 atm of pressure. This is independent of the radius of the column”



So if the effect of mercury is INDEPENDENT of the radius of the column, why does TBR say it has to be over a “UNIT AREA”?

 

[NextStepTutor_2]

Pressure is defined as force over area. Let's hypothetically increase the cross sectional area of this column. For this larger "slice" of water, you would also increase the force due to gravity. Pressure (F/A) remains 1atm.

 

[justadream]

@NextStepTutor_2

Right, so technically, there's no reason to say "unit area" then right?