http://www.ck12.org Chapter 11. Wave Motion and Sound
a) If you blow in each of these tubes, which (A,B,C) will produce the highest frequency sound?
b) What is the wavelength of the 1st harmonic (i.e. fundamental) of tube B?c) The speed of sound at room temperature is about 343 m/s. What is the frequency of the 1st harmonic for tube B?
Solution
a) The water forms the bottom of the tube and thus where the node of the wave will be. Thus the air column is
where the sound wave can exist. The larger the air column, the larger the wavelength. Frequency is inversely
proportional to wavelength, thus the tube with the smallest air column will have the highest frequency. So the
answer is tube C.
b) The air column is 50 cm - 20 cm = 30 cm. The first harmonic has a quarter wavelength in the tube. Thus
λ= 4 ×L. Thus,λ= 4 ×30cm=120cm
c) Using the wave equation for the first harmonic (thus, n = 1) of a tube open at one end we get
f= 4 vL=^3431. 2 m/sm =286HzWatch this Explanation
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