When two sound waves are superimposed,beats are produced when they have

$56$ tuning forks are arranged in increasing order of frequencies in a series such that each fork gives $4 \text{ beats per second}$ with the previous one. The frequency of the last fork is the octave of the first. The frequency of the first fork is ..... $Hz$.

Two sitar strings,$A$ and $B$,playing the note $'Dha'$ are slightly out of tune and produce beats at a frequency of $5 \, Hz$. The tension of string $B$ is slightly increased and the beat frequency is found to decrease to $3 \, Hz$. If the frequency of $A$ is $425 \, Hz$,the original frequency of $B$ is ... $Hz$.

The wavelengths of two sound notes in air are $\frac{40}{195} \,m$ and $\frac{40}{193} \,m$. Each note produces $9$ beats per second separately with a third note of fixed frequency. The velocity of sound in air in $m/s$ is

Two identical wires have the same fundamental frequency of $400 \text{ Hz}$ when kept under the same tension. If the tension in one wire is increased by $2\%$,the number of beats produced will be

The air columns in two tubes closed at one end vibrating in their fundamental modes produce $2$ beats per second. The number of beats produced per second when the same tubes are vibrated in their fundamental mode with their both ends open are