In an open end manometer,one end of a U-tube filled with mercury is attached to a gas-filled container and the other end is open to the atmosphere.If the gas pressure in the container is less than atmospheric pressure
A)Hg will be forced out of the open end of the U-tube.
B)the difference between the Hg levels in the two arms will be greater than 76 cm.
C)the Hg level will be higher in the arm connected to the container.
D)the Hg level will be higher in the arm open to the atmosphere.

Question

Quizplus · Accepted Answer

In an open end manometer, the height difference of the mercury in the two arms represents the difference in pressure between the gas in the container and atmospheric pressure. If the gas pressure is less than atmospheric pressure, then the mercury level in the arm connected to the container will be lower, since the atmospheric pressure is pushing down on the open end of that arm. This causes the mercury to move towards the arm connected to the container, making its level higher. Therefore, option C is the correct choice. Option A is incorrect because mercury cannot be forced out of the open end of the U-tube due to the cohesive forces of the mercury molecules. Option B is incorrect because the maximum height difference in an open-end manometer is 76 cm, which is the atmospheric pressure. Option D is incorrect because the Hg level will be higher in the arm connected to the container, not in the arm open to the atmosphere.

In an Open End Manometer,one End of a U-Tube Filled