ECHO
An echo is a repeating sound caused by sound waves being reflected back. Sound waves may bounce off smooth, hard objects in the same manner as a rubber ball does. Despite the fact that the sound’s direction changes, the echo sounds exactly like the original. Echoes can be heard in confined places with hard walls, such as wells, or in areas with a lot of hard surfaces. Echoes may be herded together in a canyon, cave, or mountain range. However, not all noises are reflected. If they come into contact with a soft surface, such as a cushion, they will be absorbed and will not bounce back.
Minimum Distance Required To Hear An Echo
An echo is only heard if the distance between the person making the sound and the stiff obstruction is sufficient for the reflected sound to reach the person at least 0.1 seconds after the original sound is heard. Otherwise, the echo is undetectable even when it reaches the ears. This value may be computed and is 17.2 m for air and 70 m for water.
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Refraction of Sound
A sound is a vibration that travels as a mechanical wave across a medium. It can spread via a solid, a liquid, or a gas as the medium. In solids, sound travels the quickest, comparatively more slowly in liquids, and the slowest in gases.
A sound wave is a pattern of disturbance caused by energy travelling away from the sound source. The constituents of sound are longitudinal waves. This demonstrates that vibrational particle propagation and the direction of energy wave propagation are parallel. When made to vibrate, atoms begin to oscillate. This continuous back-and-forth motion results in the formation of a high-pressure and a low-pressure zone in the medium.
These high- and low-pressure zones are called compressions and rarefactions, respectively. As a result of these locations transmitting to the surrounding media, the sound waves go from one to the other.