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 .... $cm$.

The second overtone of an open organ pipe is equal to the first overtone of a closed organ pipe. If the length of the closed organ pipe is $15 \ cm$,the length of the open organ pipe is: (in $cm$)

$A$ pipe of length $1.5\ m$ closed at one end is filled with gas and resonates in its fundamental mode with a tuning fork. Another open organ pipe of same dimensions filled with air resonates in its fundamental mode with the same tuning fork. If the experiment is performed at $30\,^{\circ}C$ (speed of sound in air is $360\ m/s$ at $30\,^{\circ}C$),the speed of sound at $0\,^{\circ}C$ in the gas is ...... $m/s$ (Neglect end correction).

What kind of figures are possible for a closed pipe?

The frequency of the third overtone of a pipe of length $L_c$,closed at one end,is the same as the frequency of the sixth overtone of a pipe of length $L_o$,open at both ends. Then the ratio $L_c : L_o$ is

$A$ resonance tube completely filled with water has a small hole at the bottom. Length of the tube is $0.8 \ m$. $A$ vibrating tuning fork of frequency $500 \ Hz$ is held near the open end of the tube. Water is slowly removed from the bottom. The maximum number of resonances heard will be (Neglect end correction. Speed of sound in air $= 340 \ m/s$).