There are three sources of sound of equal intensity with frequencies $400, 401$ and $402\, vib/sec.$ The number of beats heard per second is

$A$ 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 $Hz$?

$5\, \text{beats/second}$ are heard when a tuning fork is sounded with a sonometer wire under tension, when the length of the sonometer wire is either $0.95\, \text{m}$ or $1\, \text{m}$. The frequency of the fork will be ... $\text{Hz}$.

$A$ tuning fork of frequency $n$ produces $x$ beats per second when sounded with a vibrating sonometer string. What must have been the frequency of the string, when a slight increase in tension produces lesser beats per second than before?

$A$ set of $28$ tuning forks is arranged in an increasing order of frequencies. Each fork produces '$x$' beats per second with the preceding fork and the last fork is an octave of the first. If the frequency of the $12^{\text{th}}$ fork is $152 \text{ Hz}$,the value of '$x$' (number of beats per second) is:

Two tuning forks $A$ and $B$ vibrating simultaneously produce $5$ beats. The frequency of $B$ is $512 \ Hz$. It is observed that if one arm of $A$ is filed,the number of beats increases. The frequency of $A$ is: (in $Hz$)