Question

If a barometer is kept on the earth's surface then calculate the height of the barometer column $h$.
Atmospheric Pressure ($P_a$) is ${10}^5$.
The density of mercury (${\rho }_m$) is $13600kg{m}^{-3}$.
Gravitational acceleration ($g$) near earth's surface is $10m{s}^{-2}$.

Answer 1

Given:
Acceleration due to gravity, $g=10m{s}^{-2}$
Density of mercury, ${\rho }_m=13600kg{m}^{-3}$
Atmospheric Pressure, $P_a={10}^{5}Pa$

The weight of the liquid in the column balances the atmospheric pressure in the barometer.
${\rho }_{m}gh=P_a$
$13600\times h\times 10={10}^5$
$h=0.735m\approx 74cm$