Decibel is the unit of

In a test,a subsonic jet flies overhead at an altitude of $100 \, m$. The sound intensity level on the ground as the jet passes overhead is $160 \, dB$. At what altitude should the plane fly so that the ground noise is not greater than $120 \, dB$?

In a city,the sound intensity level increases uniformly by about $1 \ dB$ annually. How many years will it take for the intensity of sound to become double?

To raise the pitch of a stringed musical instrument,the player can:

$A$ small speaker delivers $2\, W$ of audio output. At what distance from the speaker will one detect $120\, dB$ intensity sound in $cm$?

The walls of the halls built for music concerts should