Q 10.22 A manometer reads the pressure of a gas in an enclosure as shown in Figure (a) When a pump removes some of the gas, the manometer reads as in Figure (b) The liquid used in the manometers is mercury and the atmospheric pressure is 76 cm of mercury. 

(b) 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?


Answers (1)
S Sayak

As we know Specific Gravity of Mercury is 13.6 therefore 13.6 cm of water column would be equal to  1 cm of Mercury column.

The pressure at the Mercury Water interface in the right column = Atmospheric Pressure + 1 cm of Mercury = 77 cm of Mercury

The difference in Pressure due to the level of the Mercury column = Pressure at the Mercury Water interface - Absolute Pressure of the Glass enclosure

                                                                                                   = 77 - 58 = 19 cm of Mercury.

The difference in the two limbs would, therefore, become 19 cm.