When a tuning fork produces sound waves in air,which one of the following remains the same in the material of the tuning fork as well as in the air?

Two perfectly identical wires are in unison. When the tension in one wire is increased by $1\%$,then on sounding them together $3$ beats are heard in $2 \,s$. The initial frequency of each wire is .... $\text{s}^{-1}$.

The beats are produced when there is a superposition of two sound waves which have:

$A$ tuning fork $A$ of unknown frequency produces $5 \, beats/s$ with a fork of known frequency $340 \, Hz$. When fork $A$ is filed,the beat frequency decreases to $2 \, beats/s$. What is the frequency of fork $A$ in $Hz$?

The frequency of a tuning fork is $256 \ Hz$. It will not resonate with the tuning fork of frequency (in $Hz$)

Two sitar strings $A$ and $B$ playing the note '$Ga$' are slightly out of tune and produce beats of frequency $6 \; Hz$. The tension in the string $A$ is slightly reduced and the beat frequency is found to reduce to $3 \; Hz$. If the original frequency of $A$ is $324 \; Hz$,what is the frequency (in $Hz$) of $B$?