$A$ $1 \; m$ long (both ends open) organ pipe is kept in a gas that has double the density of air at $STP$. Assuming the speed of sound in air at $STP$ is $300 \; m/s$,the frequency difference between the fundamental and second harmonic of this pipe is . . . . . . $Hz$.

The frequency of the fourth overtone of a closed pipe is in unison with the fifth overtone of an open pipe. The ratio of the length of the closed pipe to that of the open pipe is

$A$ whistle whose air column is open at both ends has a fundamental frequency of $5100 \ Hz$. If the speed of sound in air is $340 \ ms^{-1}$, the length of the whistle, in $cm$, is

The first overtone frequency of a closed pipe of length $l_{1}$ is equal to the $2^{\text{nd}}$ harmonic frequency of an open pipe of length $l_{2}$. The ratio $\frac{l_{1}}{l_{2}}$ is:

Give the equation for the normal modes of vibration for a closed pipe.

An open organ pipe and a closed organ pipe of the same length $L$ produce $2$ beats per second when they are set into vibrations together in their fundamental modes. The length of the open pipe is made half and that of the closed pipe is doubled. The number of beats produced per second will be (neglect end correction).