MCQ Detailed View

A manometer is an instrument used to measure pressure differences between a gas and the atmosphere or between two gases. It typically consists of a U-shaped tube filled with a liquid, such as mercury or water. One column of the manometer is open to the atmosphere or a reference pressure, while the other column is connected to the system whose pressure is being measured.

When the gas pressure is less than the reference pressure (or atmospheric pressure), the column of the manometer that faces the liquid connected to the gas is depressed. This occurs because the higher pressure on the other side pushes the liquid down, lowering the height of the liquid column on the side facing the gas. The difference in heights of the two columns represents the pressure difference.

Other options are incorrect. If the gas pressure were higher, the column facing the liquid would be raised, not depressed. The terms compressed or remains the same do not accurately describe the behavior of the manometer liquid in response to pressure differences.

Manometers are widely used in physical chemistry experiments, engineering applications, and fluid mechanics studies. Understanding how the liquid column behaves under different pressure conditions helps students calculate gas pressures, vacuum pressures, and pressure drops in systems accurately.

By observing the depression of the liquid column, one can determine relative pressures, verify pressure trends, and understand fundamental concepts of hydrostatics and fluid equilibrium.

Thus, in a manometer, the column facing the liquid is depressed when the connected pressure is lower than the reference, making this an essential principle in pressure measurement and physical chemistry.