Open Pipe Questions - Use $343 \mathrm{~m} / \mathrm{s}$ as the speed of sound.
Example: An open pipe is made to play a note of $B$ at a frequency of $123.48 \mathrm{~Hz}$. Calculate what length this pipe needs to be to make this note.

Step 1 ：Given that the speed of sound in air is \(v = 343 \mathrm{~m/s}\) and the frequency of the note is \(f = 123.48 \mathrm{~Hz}\).

Step 2 ：We can calculate the wavelength of the sound using the formula \(v = f \lambda\), where \(\lambda\) is the wavelength. Rearranging the formula gives us \(\lambda = \frac{v}{f}\).

Step 3 ：Substituting the given values into the formula, we get \(\lambda = \frac{343}{123.48} = 2.7777777777777777\).

Step 4 ：For an open pipe, the length of the pipe is half the wavelength of the sound. Therefore, we can calculate the length of the pipe by dividing the wavelength by 2. This gives us \(\text{pipe length} = \frac{\lambda}{2} = 1.3888888888888888\).

Step 5 ：Final Answer: The length of the pipe needs to be approximately \(\boxed{1.39 \mathrm{~m}}\) to play a note of $B$ at a frequency of $123.48 \mathrm{~Hz}$.