question_answer

A vessel is placed below a water-tap. We can estimate the height of water level reached in the vessel from a distance simply by listening the sound. How?

Answer:

                The frequency of the note produced by an air column is inversely proportional to its length. As the level of water in the vessel rises, the length of the air column above it decreases. It produces sound of decreasing frequency i.e., the sound becomes shriller. From the extent of shrillness of sound, we can estimate the height up to which the vessel has been filled with water.