If the seventh harmonic of a closed organ pipe is in unison with the fourth harmonic of an open organ pipe, then the ratio of the length of the closed pipe to that of the open pipe is:

Air columns in two identical tubes are vibrating. Tube $A$ has one end closed and tube $B$ has both ends open. Neglecting end correction,the ratio of the fundamental frequency of the air column in tube $A$ to that in tube $B$ is

$A$ pipe open at both ends has a fundamental frequency $f$ in air. The pipe is dipped vertically in water so that half of its length is in water. The fundamental frequency of the air column is now ..... $f$.

On closing an open organ pipe from one end, it is noticed that the frequency of the third harmonic is $50 \,Hz$ more than the fundamental frequency of vibration in the open organ pipe. The fundamental frequency of the open organ pipe is (in $\,Hz$)

$A$ student is performing the Resonance Column experiment. The diameter of the column tube is $4 \ cm$. The frequency of the tuning fork is $512 \ Hz$. The air temperature is $38^{\circ} C$,at which the speed of sound is $336 \ m/s$. The zero of the meter scale coincides with the top end of the resonance column. When the first resonance occurs,the reading of the water level in the column is: (in $cm$)

If $v$ is the speed of sound in air,then what is the shortest length of a closed pipe that resonates at a frequency $n$?