Sound waves produce echo primarily due to [C] reflection. When sound travels and encounters a sufficiently large and hard surface, such as a solid wall, mountain, or canyon wall, it reflects off the surface rather than passing through it or bending (refraction and diffraction).

The reflection of sound waves causes them to bounce back towards the source or in other directions, depending on the angle of incidence and the surface characteristics. If the distance to the reflecting surface is significant enough, the reflected sound waves return to the listener’s ears after a noticeable delay, creating the perceptible phenomenon known as an echo.

Understanding the process of reflection and its role in producing echoes is essential for designing spaces, conducting acoustic measurements, and studying sound propagation in various environments, from natural landscapes to built structures.