$A$ pipe $30 \ cm$ long is open at both ends. Which harmonic mode of the pipe is resonantly excited by a $1.1 \ kHz$ source? (Take speed of sound in air = $330 \ ms^{-1}$)

$A$ person blows into the open end of a long pipe. As a result,a high-pressure pulse of air travels down the pipe. When this pulse reaches the other end of the pipe,which of the following statements are true?
$(I)$ $A$ high-pressure pulse starts travelling up the pipe,if the other end of the pipe is open.
$(II)$ $A$ low-pressure pulse starts travelling up the pipe,if the other end of the pipe is open.
$(III)$ $A$ low-pressure pulse starts travelling up the pipe,if the other end of the pipe is closed.
$(IV)$ $A$ high-pressure pulse starts travelling up the pipe,if the other end of the pipe is closed.

$A$ 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.

$A$ cylindrical tube $(L = 120\,cm)$ is resonant with a tuning fork of frequency $330\,Hz$. If it is being filled with water,what is the minimum length of the water column required to achieve resonance? (Speed of sound in air $V_{air} = 330\,m/s$)

The fundamental frequency of an air column in a pipe closed at one end is $150 \ Hz$. If the same pipe is open at both ends,the frequencies produced in $Hz$ are:

$A$ 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