How does the inverse-square law relate to sound and altitude?

The inverse-square law is a fundamental principle that describes how the intensity of a physical quantity, like sound, decreases with distance from its source. When we refer to sound intensity in this context, it means that as you move away from the sound source, the intensity (which can be thought of as the power per unit area) diminishes in proportion to the square of the distance from that source.

This relationship occurs because sound waves emanate in all directions from a point source and spread out over a larger area as they travel further away. Specifically, if you double the distance from the sound source, the sound intensity is reduced by a factor of four (since 2 squared is 4). Therefore, the correct understanding of the inverse-square law in relation to sound indicates that as you distance yourself from a sound source, its intensity decreases sharply.

In contrast, other choices suggest that sound intensity either remains constant or increases with altitude, which does not align with the principles of the inverse-square law or the behaviors of sound propagation in the atmosphere. Although altitude can affect sound propagation through factors such as temperature and atmospheric pressure, the basic relationship defined by the inverse-square law remains true regardless of those variables.