Three sound waves of equal amplitudes have frequencies $(f-1)$,$f$,and $(f+1)$. They superpose to produce beats. The number of beats produced per second will be:

Two tuning forks $A$ and $B$ are sounded together and produce $6$ beats per second. The frequency of tuning fork $B$ is $384 \,Hz$. When tuning fork $A$ is loaded with wax,the number of beats per second becomes $4$. What is the frequency of tuning fork $A$ in $Hz$?

Two adjacent piano keys are struck simultaneously. The notes emitted by them have frequencies $n_1$ and $n_2$. The number of beats heard per second is

$A$ tuning fork of known frequency $256\,Hz$ produces $5$ beats per second with the vibrating string of a piano. The beat frequency decreases to $2$ beats per second when the tension in the piano string is slightly increased. The frequency of the piano string before increasing the tension was

$A$ tuning fork arrangement (pair) produces $4 \, beats/sec$ with one fork of frequency $288 \, cps$. $A$ little wax is placed on the unknown fork and it then produces $2 \, beats/sec$. The frequency of the unknown fork is .... $cps$.

$A$ vibrating tuning fork of frequency $n$ is placed near the open end of a long cylindrical tube. The tube has a side opening and is fitted with a movable reflecting piston. As the piston is moved through $8.75 \, cm$,the intensity of sound changes from a maximum to a minimum. If the speed of sound is $350 \, m/s$,then $n$ is .... $Hz$.