$A$ 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 $Hz$)

Two tuning forks with frequencies $380 \,Hz$ and $384 \,Hz$ are sounded together. They produce $4$ beats per second. What is the time interval between the maximum sound and the next minimum sound?

It is possible to hear beats from two vibrating sources of frequency:

$A$ 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 $\dots \; Hz$.

Two sitar strings $A$ and $B$ playing the note $Sa$ are slightly out of tune and produce beats of frequency $5 \ Hz$. The tension of the string $B$ is slightly decreased and the beat frequency is found to decrease to $3 \ Hz$. What is the original frequency of $B$,if the frequency of $A$ is $255 \ Hz$?

Tuning fork $F_1$ has a frequency of $256 Hz$ and it is observed to produce $6$ beats/second with another tuning fork $F_2$. When $F_2$ is loaded with wax,it still produces $6$ beats/second with $F_1$. The frequency of $F_2$ before loading was ..... $Hz$.