When a tuning fork produces sound waves in air,which one of the following remains the same in the material of the tuning fork as well as in the air?

$41$ tuning forks are arranged in increasing order of frequency such that each produces $5 \text{ beats/second}$ with the next tuning fork. If the frequency of the last tuning fork is double that of the frequency of the first fork,then the frequency of the first and last fork is:

The number of beats produced per second by two vibrations: $x_1 = x_0 \sin(646\pi t)$ and $x_2 = x_0 \sin(652\pi t)$ is

When a tuning fork is vibrating,the vibrations of the two prongs

$A$ tuning fork of frequency $400 \ Hz$ is in unison with a sonometer wire. The number of beats heard per second,when the tension in the wire is increased by $1 \%$,will be

$56$ 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 ..... $Hz$.