Reflected sound waves are called _____.

Hint We know that light rays get reflected when it hits a hard surface with little or no loss of amplitude. Just like a light wave, a sound wave also gets reflected when it hits a hard surface. This results in the bouncing back of waves of similar but lesser amplitude sounds.

Complete Step by step solution
Reflection of sound waves from a surface is called an echo or a reverberation. Sound waves can bounce off smooth or rough surfaces. It follows the law of reflection just like a light wave. After reflection, the reflected sound waves generally have less energy compared to the incident sound wave, or less amplitude compared to the incident sound wave. This is the reason that the reflected sound waves or the echoes seem like they are of lower sound quality as compared to the original sound.
Echoes are generally created inside a room, or a well or an enclosed space, etc whose dimensions are approximately $17m$ . The human brain retains a sound for about one-tenth of a second. As the speed of the sound wave is approximately $340m/s$ , the sound wave will take approximately one-tenth of a second to travel back and forth a distance of $17m$ . So, by the time the original sound wave memory is lost from our brain, the next set of waves that was reflected from surfaces approaches our ears at about one-tenth of a second. So, the sound seems to be prolonged for us which is the echo.

Note
Sound waves do not always reflect off soft bodies because soft bodies absorb the sound wave. So, in an echo-free chamber, all the surfaces that cover the outside surroundings are made with soft foam shapes so that the sound waves will get absorbed.