Four tuning forks of frequencies $200 \, Hz, 201 \, Hz, 204 \, Hz$ and $206 \, Hz$ are sounded together. The beat frequency will be

Two tuning forks $A$ and $B$ produce notes of frequencies $256 \ Hz$ and $262 \ Hz$ respectively. An unknown note sounded at the same time as $A$ produces beats. When the same note is sounded with $B$,the beat frequency is twice as large. The unknown frequency could be ... $Hz$

$A$ set of $20$ tuning forks is arranged in a series of increasing frequencies. If each fork gives $4 \; Hz$ beats with respect to the preceding fork and the frequency of the last fork is twice the frequency of the first,then the frequency of the last fork is $\dots \; Hz$.

$A$ 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 $Hz$?

$A$ tuning fork $A$ of frequency $200 \ Hz$ is sounded with fork $B,$ the number of beats per second is $5.$ By putting some wax on $A,$ the number of beats increases to $8.$ The frequency of fork $B$ is .... $Hz$

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