Question

Consider a cylindrical pipe with both ends open and fundamental resonance frequency 150 Hz. If this particular pipe has a length of L, what the wavelengths of three lowest modes produced by this pipe? Select an answer and submit. For keyboard navigation, use the up/down arrow keys to select an answer. a. L,2L, 3L b. 2L, L, 2L/3 с. 2L/3, L, 2L d. L, L/2, L/3 e. 4L, 24, 4L/3 f. 4L, 4L/3, 4L/5 g. Neither of above.

Answer 1

answers, the correct one is b

Step-by-step explanation:

For this problem we use the fact that since the ends are open at these points we have a maximum,

fundamental L =λ/2 λ = 2L

second harmonic L = λ λ = 2L / 2

third harmonic L = 3 λ/2 λ = 2L / 3

n harmonic lam = 2L / n

with n an integer

therefore the length of the first three harmonics are: 2L, L, 2L / 3

when examining the different answers, the correct one is b