Answer:
dβ = 70. 77 dβ
Explanation:
The intensity of sound in decibels is
dβ = 10 log I/I₀
let's look for the intensity of this signal
I / I₀ = 10 dβ/10
I / I₀ = 3.981 10⁶
the threshold intensity of sound for humans is I₀ = 1 10⁻¹² W / m²
I = 3.981 10 ⁶ 1 10⁻¹²
I = 3,981 10⁻⁶ W / m²
It is indicated that 3 cornets are placed in the circle, for which total intensity is
I_total - 3 I
I_total = 3 3,981 10⁻⁶
I_total = 11,943 10⁻⁶ W / m²
let's reduce to decibels
dβ = 10 log (11,943 10⁻⁶/1 10⁻¹²)
dβ = 10 7.077
dβ = 70. 77 dβ