$P$ and $Q$ are two wires whose fundamental frequencies are $256 \ Hz$ and $382 \ Hz$ respectively. How many beats per second will be heard if the third harmonic of $P$ and the second harmonic of $Q$ are sounded together?

For the formation of beats,two sound notes must have:

Two wires are producing fundamental notes of the same frequency. Change in which of the following factors of one wire will not produce beats between them?

$A$ tuning fork gives $3$ beats with $50 \ cm$ length of sonometer wire. If the length of the wire is shortened by $1 \ cm$,the number of beats is still the same. The frequency of the fork is (in $Hz$)

When a tuning fork of frequency $341 \ Hz$ is sounded with another tuning fork,six beats per second are heard. When the second tuning fork is loaded with wax and sounded with the first tuning fork,the number of beats is two per second. The natural frequency of the second tuning fork is: (in $Hz$)

$A$ tuning fork $A$ produces $4$ beats/sec with another tuning fork $B$ of frequency $320 \text{ Hz}$. On filing the fork $A$,$4$ beats/sec are again heard. The frequency of fork $A$ after filing is .... $\text{Hz}$