The sound level, G, in decibels (dB), of a sound with an intensity of $I$ is calculated in relation to the threshold of human hearing, $I_0$, by this equation:<br /> $\beta=10 \log \left(\frac{I}{I_0}\right)$<br /> <br /> The threshold of human hearing is $10^{-12}$ watts/meter$^2$.<br /> The sound level of a jet plane is approximately 140 dB. The intensity of the sound of a jet plane is approximately □ watts/meter$^2$.