contestada

In which one of the following locations can a person hear the echo of a sound?

A. At least 33.2 meters behind the reflecting surface
B. At least 16.6 meters in front of the reflecting surface
C. Less than 16.6 meters in front of the reflecting surface
D. Less than 33.2 meters behind the reflecting surface

Respuesta :

At least 16.6 meters in front of the reflecting surface

Explanation :

When we hear a sound, again and again, it is called the echo of the sound. In the human brain the persistence of the sound remains for 0.1 seconds.

The speed of the sound at room temperature is 344 m/s. We know that the speed of the sound wave is given by :

[tex]v=\dfrac{d}{t}[/tex]

d is the distance covered by the sound from point of generation of the sound to the reflecting surface and back.

[tex]d=vt[/tex]

[tex]d=34.4\ m[/tex]

For hearing the echo of a sound, the distance covered by the sound in one way should be 17.2 m/s

So, the correct option is (B) "At least 16.6 meters in front of the reflecting surface".