Answer:
The new intensity becomes (1/9) of the initial intensity.
Step-by-step explanation:
A source radiates sound uniformly in all directions and its intensity is proportional to the distance as follows :
![I\propto (1)/(r^2)](https://img.qammunity.org/2021/formulas/physics/college/y1r9fsu6c3os3oh4vfcld6gs8n3m75o7fz.png)
Let I₁ and I₂ be the intensities at a distance r₁ and r₂. So,
![(I_1)/(I_2)=(r_2^2)/(r_1^2)](https://img.qammunity.org/2021/formulas/physics/college/y8daa6rcmfmvfy3jgu179ajkoldhdmyi5a.png)
We have, r₂ = 3r₁
![(I_1)/(I_2)=(9r_1)/(r_1)\\\\(I_1)/(I_2)=9\\\\I_2=(I_1)/(9)](https://img.qammunity.org/2021/formulas/physics/college/1vbq3zn3nkoaw1x0ljs72sesg6tadfstyq.png)
Hence, the new intensity becomes (1/9) of the initial intensity.