Question

What will be the length of mercury column in a barometer tube, when the atmospheric pressure is $75\, cm$ of mercury and the tube is inclined at an angle of $60^{\circ}$ to the vertical?

Answer 1

Let $l$ be length of the mercury column in the barometer tube. As the barometer tube is inclined at an angle of $60^{\circ}$ to the vertical, effective height (vertical) of the mercury column $=l \cos 60^{\circ}$. Since atmospheric pressure is $75\, cm$ of mercury column, $l \cos 60^{\circ}=75$
or $l=\frac{75}{\cos 60^{\circ}}=\frac{75}{1 / 2}=150\, cm$