The sound produced by the speakers at a rock concert has a power of 0.181 W. What sound intensity do you hear when you are standing 20.5 m away?

The sound intensity heard standing 20.5 m away = 0.0000343 W/m² = 3.43 × 10⁻⁵ W/m²

Explanation:

Intensity of sound at some distance r away is calculated as (power of the sound/surface area of wall of imaginary sphere at distance r)

Power of the sound = 0.181 W

Surface area of wall of imaginary sphere = 4πr² = 4π(20.5²) = 5281.02 m²

Intensity = 0.181/5281.02 = 0.0000343 W/m² = 3.43 × 10⁻⁵ W/m²