Which of the following describes a condition in which an individual would not hear an echo?


A. An individual is standing 30 meters in front of the reflecting surface.

B. The reflecting source is approximately 21.5 meters from the individual.

C. An individual is standing in the range of the sound waves coming from the original sound source as well as the reflected waves.
D. A sound wave reaches the ear and the reflected wave reaches the ear less than 0.1 second later.

Respuesta :

D- A sound wave reaches the ear and the reflected wave reaches the ear less than 0.1 second later.

The correct answer is D.

Echo refers to the sound that is heard when a sound wave is reflected back from a surface. An echo sound is made when a sound wave traveled through the air, hit a hard surface and get reflected back. Generally, hard surfaces reflect sound wave while soft surfaces absorb sound waves. Reflected sound waves are used in application of some devices that are used in range and direction finding.