$A$ closed pipe of length $300 \,cm$ contains some sand. $A$ speaker is connected at one of its ends. The frequency of the speaker at which the sand will arrange itself in $20$ equidistant piles is close to .......... $kHz$ (velocity of sound is $300 \,m/s$).

$A$ glass tube $1.5 \ m$ long and open at both ends is immersed vertically in a water tank completely. $A$ tuning fork of $660 \ Hz$ is vibrated and kept at the upper end of the tube,and the tube is gradually raised out of the water. Taking the velocity of sound in air as $330 \ m/s$,find the total number of resonances heard before the tube comes out of the water.

The first resonance length of a resonance tube is $40\, cm$ and the second resonance length is $122\, cm$. The third resonance length of the tube will be... $cm$

The fundamental frequency in an open organ pipe is equal to the third harmonic of a closed organ pipe. If the length of the closed organ pipe is $20 \ cm$,the length of the open organ pipe is .... $cm$.

An organ pipe closed at one end has a fundamental frequency of $1500 \ Hz$. The maximum number of overtones generated by this pipe which a normal person can hear is ($A$ normal person can hear frequencies up to $19.5 \ kHz$,neglect end correction).

An organ pipe of length $L$ open at both ends is found to vibrate in its first harmonic when sounded with a tuning fork of $480 \ Hz$. What should be the length of a pipe closed at one end,so that it also vibrates in its first harmonic with the same tuning fork?