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

Beats are the result of

The correct figure that shows,schematically,the wave pattern produced by the superposition of two waves of frequencies $9\,Hz$ and $11\,Hz$ is:

$A$ vibrating tuning fork of frequency $n$ is placed near the open end of a long cylindrical tube. The tube has a side opening and is fitted with a movable reflecting piston. As the piston is moved through $8.75 \, cm$,the intensity of sound changes from a maximum to a minimum. If the speed of sound is $350 \, m/s$,then $n$ is .... $Hz$.

Two identical piano wires have a fundamental frequency of $600 \text{ Hz}$ when kept under the same tension. What fractional increase in the tension of one wire will lead to the occurrence of $6$ beats per second when both wires vibrate simultaneously?

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