Answer:
<em> The intensity would be 0.01432 W/</em><em></em>
Explanation:
The sound intensity is the power that is transmitted by a sound wave per unit area.
Given that
Power output P of the 75-piece orchestra = 72.0 W
The listener's distance r = 20.0 m
The intensity of sound waves (I) can be obtained with the expression below;
I = P/A .............. 1
where P is the power
A is the area, in this case, at the distance r the sound is radiated through a sphere.
A = area of a sphere = 4π
putting it into equation 1, the intensity would be;
I = P/ 4π
Substituting our values we have;
I = 72.0 W / 4 π
I = 0.01432 W/
Therefore the intensity would be 0.01432 W/