$A$ source of frequency $\nu$ gives $5$ beats/second when sounded with a source of frequency $200 \;Hz$. The second harmonic of frequency $2\nu$ of the source gives $10$ beats/second when sounded with a source of frequency $420 \;Hz$. The value of $\nu$ is .... $Hz$.

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

Two tuning forks $A$ and $B$ are sounded together giving rise to $8$ beats in $2$ s. When fork $A$ is loaded with wax, the beat frequency is reduced to $4$ beats in $2$ s. If the original frequency of tuning fork $B$ is $380$ Hz, then the original frequency of tuning fork $A$ is . . . . . . Hz.

The ratio of intensities between two coherent sound sources is $4:1$. The difference of loudness in $dB$ between maximum and minimum intensities when they interfere in space is:

The maximum number of beats per second that a human ear can distinguish is

The sound waves of wavelengths $5 \,m$ and $6 \,m$ produce $30$ beats in $3 \,s$. The velocity of sound is (in $\,m/s$)