The walls of the halls built for music concerts should

$A$ musical scale is constructed by providing intermediate frequencies between a note and its octave which:

If the threshold of hearing is assumed to be the reference $(0 \ dB)$,then the threshold of pain is taken to be $120 \ dB$. Let the corresponding sound intensities be $I_0$ and $I$ respectively. Then $\frac{I_0}{I}$ is:

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

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

Out of the following musical instruments, which is '$NOT$' a percussion instrument?