how is an echo formed

Question

Light waves pass through a shiny surface
Sound waves travel into a soft surface
Sound waves bounce off a flat surface
Light waves go around a smooth surface

Answer 1

An echo is formed when sound waves bounce off a flat surface and travel back to the source of the sound. When a sound wave reaches a solid, reflective surface such as a wall or a mountain, it reflects, or bounces back, in the opposite direction. This reflected sound wave travels through the air back to the source, creating the perception of an echo. The time delay between the original sound and the echo is determined by the distance between the sound source and the reflecting surface.