A flask containing helium gas is connected to an open-ended mercury manometer. The open end is exposed to the atmosphere, where
the prevailing pressure is 752 torr. The mercury level in the open arm is 26 mm above that in the arm connected to the flask of helium.What is the helium pressure, in torr?
Generally, atmospheric pressure can be measured using a manometer which is in form of a U-shaped tube. In addition, 1 mm Hg is equivalent to 1 torr. Therefore, 752 torr is equivalent to 752 mm Hg. Therefore, the total pressure will be equivalent to the atmospheric pressure (mm Hg) + the mercury height.
