Q. A barometer tube reads $75\, cm$ of $Hg$. If tube is gradually inclined at an angle of $30^{\circ}$ with horizontal, keeping the open end in the mercury container, then find the length of mercury column in the barometer tube
Mechanical Properties of Fluids
Solution:
$\because$ We are not changing the atmospheric pressure, so height of $Hg$ from the surface should not change.
$\frac{75}{x}=\cos 60^{\circ}$
$\Rightarrow x=150\, cm$
