How is an echo formed?(1 point)
An echo is formed when sound waves are reflected off of a surface, such as a wall or cliff, and return to the listener.
An echo is formed when sound waves reflect off a surface and reach our ears after a delay. Here is how an echo is formed:
1. A sound is produced: An initial sound wave is generated by a source, such as a person speaking, a musical instrument, or any other noise-producing object.
2. Sound waves travel: The sound waves radiate out from the source in all directions, propagating through the air or any other medium present.
3. Reflection: Some of the sound waves encounter a large, flat, and hard surface, such as a wall, building, or cliff. When the sound wave hits the surface, it reflects back towards the source of the sound.
4. Time delay: The reflected sound wave travels back towards the source, causing a delay in reaching our ears. This delay is due to the extra distance the sound wave has to cover while traveling to the reflecting surface and back.
5. Audible perception: When the reflected sound finally reaches our ears, we perceive it as an echo. The delay between the initial sound and the echo typically depends on the distance between the source and the reflecting surface.
It's important to note that for an echo to be audible, the time between the initial sound and the reflected sound must be at least 0.1 seconds or 100 milliseconds.