Use R=8.3 J/mol-K wherever required. A faulty barometer contains certain amount of air and

Use $\mathrm{R}=8.3 \mathrm{~J} / \mathrm{mol}-\mathrm{K}$ wherever required.

A faulty barometer contains certain amount of air and saturated water vapour. It reads $74.0 \mathrm{~cm}$ when the atmospheric pressure is $76.0 \mathrm{~cm}$ of mercury and reads $72.10 \mathrm{~cm}$ when the atmospheric pressure is $74.0 \mathrm{~cm}$ of mercury. Saturation vapour pressure at the air temperature $=1.0 \mathrm{~cm}$ of mercury. Find the length of the barometer tube above the mercury level in the reservoir.