[sagrr]

Why does the height of mercury in a barometer independent of the cross-sectional area of the tube?

Would the baromenter still work if it were at an angle?

... read through the section twice and couldn't find the answer


very confuzed  :1eye:

[Donaldson Tan]

the attached diagram is mercury barometer.

the blue point is exposed to the atmosphere, so the pressure at the blue point is 1atm.

the red point is on equal level as the blue point, so the pressure at the red point must be 1atm too.

remember that pressure (P) is given as P = H*D*g where
H: height
D: density
g: gravitational acceleration.

since H = P/(D*g) and P is already known, and D & g are constants, then the height of the mercury column must be dependent on the external pressure and independent of the barometer cross section area.