Question

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

Answer 1

Answer: 150

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 $75cm$ of mercury column, $l\cos 60^{\circ }=75$
or $l=\frac{75}{\cos 60^{\circ }}=\frac{75}{1/2}=150cm$