Answer
The loudness of this sound level is about 65 decibels.
Work Step by Step
The intensity of the sound in a normal conversation is about $\text{3}\text{.2}\times \text{1}{{\text{0}}^{-6}}\text{ W/}{{\text{m}}^{\text{2}}}$.
Thus, $I=3.2\times {{10}^{-6}}$.
Substitute $I=3.2\times {{10}^{-6}}$ and ${{I}_{0}}={{10}^{-12}}$ in the formula $L=10\cdot \log \frac{I}{{{I}_{\left( 0 \right)}}}$ and solve as follows:
$\begin{align}
& L=10\cdot \log \frac{I}{{{I}_{\left( 0 \right)}}} \\
& =10\cdot \log \frac{3.2\times {{10}^{-6}}}{{{10}^{-12}}} \\
& =10\cdot \log \left( 3.2\times {{10}^{-6}}\times {{10}^{12}} \right) \\
& =10\cdot \log \left( 3.2\times {{10}^{6}} \right)
\end{align}$
$\begin{align}
& L=10\cdot \log \left( 3.2\times {{10}^{6}} \right) \\
& \approx 10\cdot 6.505 \\
& \approx 65.05
\end{align}$
