In the fundamental mode,the time required for a sound wave to reach the closed end of an air-filled pipe is $t$ seconds. What is the frequency of vibration of the air column?

The two nearest harmonics of a tube closed at one end and open at the other end are $220\, Hz$ and $260\, Hz$. What is the fundamental frequency of the system in $Hz$?

In a closed organ pipe,the frequency of the fundamental note is $30 \,Hz$. $A$ certain amount of water is now poured into the organ pipe so that the fundamental frequency increases to $110 \,Hz$. If the organ pipe has a cross-sectional area of $2 \,cm^2$,the amount of water poured into the organ tube is . . . . . . $g$. (Take the speed of sound in air as $330 \,m/s$)

$A$ pipe open at both ends produces a note of frequency $f_1$. When the pipe is kept with $3/4$th of its length in water,it produces a note of frequency $f_2$. The ratio $f_1/f_2$ is

Explain the formation of stationary waves in a closed pipe and derive the equations for natural frequencies (normal modes).

This question has Statement $1$ and Statement $2.$ Of the four choices given after the Statements,choose the one that best describes the two Statements.
Statement $1:$ In the resonance tube experiment,if the tuning fork is replaced by another identical tuning fork but with its arms filed,the length of the air column should be increased to obtain resonance again.
Statement $2:$ On filing the arms,the frequency of a tuning fork increases.