$A$ 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 $300 \,m/s$).

The fundamental note produced by a closed organ pipe is of frequency $f$. The fundamental note produced by an open organ pipe of the same length will be of frequency .... $(f)$

$A$ pipe $20$ $cm$ long is closed at one end. Which harmonic mode of the pipe is resonantly excited by a source of $1237.5$ $Hz$? (Speed of sound in air $= 330$ $m/s$).

$A$ closed organ pipe and an open organ pipe of the same length produce $2 \text{ beats/second}$ while vibrating in their fundamental modes. The length of the open organ pipe is halved and that of the closed pipe is doubled. Then the number of beats produced per second while vibrating in the fundamental mode is

$A$ tuning fork of frequency '$n$' is held near the open end of a tube which is dipped in water and length of the tube is adjusted until resonance occurs. If the two shortest lengths that produce resonance are $l_1$ and $l_2$, the speed of sound in air is (neglect end correction)

$A$ tube closed at one end and containing air is excited. It produces the fundamental note of frequency $512 \ Hz$. If the same tube is open at both ends,the fundamental frequency that can be produced is .... $Hz$.