Two sound waves of slightly different frequencies have an amplitude ratio of $11/9$. What is the difference in sound levels (in decibels) between the maximum and minimum intensities heard at a point?

$A$ tuning fork $A$ produces $5$ beats per second with a tuning fork of frequency $480 \ Hz$. When a little wax is stuck to a prong of fork $A$,the number of beats heard per second becomes $2$. What is the frequency of tuning fork $A$ before the wax is stuck to it (in $Hz$)?

Two sitar strings $A$ and $B$ playing the note 'Dhai' are slightly out of tune and produce beats of frequency $5 \; Hz$. The tension of the string $B$ is slightly increased and the beat frequency is found to decrease to $3 \; Hz$. What is the original frequency of $B$ if the frequency of $A$ is $427 \; Hz$ (in $; Hz$)?

$A$ tuning fork sounded together with a tuning fork of frequency $256 \ Hz$ emits $2$ beats per second. On loading the tuning fork of frequency $256 \ Hz,$ the number of beats heard is $1$ per second. The frequency of the unknown tuning fork is: (in $Hz$)

$A$ string under a tension of $129.6 \ N$ produces $10 \ beats/s$ when it is vibrated along with a tuning fork. When the tension in the string is increased to $160 \ N$,it sounds in unison with the same tuning fork. Calculate the fundamental frequency of the tuning fork in $Hz$.

Two tuning forks,$A$ and $B$,produce $4$ beats per second when sounded together. The frequency of $A$ is $320 \ Hz$. When some wax is added to $B$ and it is sounded with $A$,$4$ beats per second are again heard. The frequency of $B$ is .... $Hz$.