A manometer reads the pressure of a gas in an exclosure as shown in fig.10.25(a) When a pump removes some of the gas, the manometer reads as in fig.10.25(b) the liquid used in the manometer is mercury and the atmospheric pressure is 76cm of mercury.
Give the absolute and gauge pressure of the gas in the exclosure for cases (a) and (b) in units of cm of mercury.
How would the levels change in case (b) If 13.6 cm of water (immiscible with mercury) are poured into the right limb of the manometer? (ignore the small change in the volume of the gas).

Explanation

Absolute pressure =96cm of Hg. Gauge pressure =20 cm of Hg for (a) absolute pressure =58 cm of Hg gauge pressure=-18 cm for Hg