Given data:
The energy of the sound increases 10 times with the increase of 10db of loudness.
Solution:
The increase in the loudness from 20 db to 50 db is,
![50-20=30\text{ db}](https://img.qammunity.org/2023/formulas/physics/college/70azs7j78d0nethrwjd08c3kjpiabr9q2v.png)
The energy of sound increases in this case is,
![\begin{gathered} 10\text{loudness = 10}*\text{ energy} \\ 30\text{ loudness }=\text{ }(10)/(10)*30* energy \\ 30\text{ loudness = 30}*\text{ energy} \end{gathered}](https://img.qammunity.org/2023/formulas/physics/college/3deuhcd734yfz7ru2rk6v8qf3jnz3fxr3a.png)
Thus, during the change of loudness from 20 db to 50 db, the energy of the sound increases by 30 times.