Answer:
0.37 m
Explanation:
The fundamental frequency of an open tube or pipe is
[tex]f_0 = \dfrac{v}{2l}[/tex]
where v is the velocity of sound and l is the length of the column.
For a closed pipe,
[tex]f_0 = \dfrac{v}{4l}[/tex]
For column A,
[tex]f_0 = \dfrac{v}{2\times0.74\text{ m}} = \dfrac{v}{1.48\text{ m}}[/tex]
For column B,
[tex]\dfrac{v}{1.48\text{ m}} = \dfrac{v}{4l}[/tex]
[tex]4l = 1.48\text{ m}[/tex]
[tex]l = 0.37\text{ m}[/tex]
