The lowest-pitch tone to resonate in a pipe of length L that is open at both ends is 200 Hz.Which one of the following frequencies will NOT resonate in the same pipe?
A) 400 Hz
B) 600 Hz
C) 800 Hz
D) 900 Hz
E) 1000 Hz

Question

Quizplus · Accepted Answer

The resonant frequencies of an open pipe of length L are given by f = nv/2L, where n is an integer and v is the speed of sound. The first resonant frequency (n = 1) is 200 Hz, so the next resonant frequency (n = 2) is 400 Hz, the next after that (n = 3) is 600 Hz, and so on. Therefore, 400 Hz, 600 Hz, and 800 Hz will all resonate in the same pipe as the lowest-pitch tone. However, 900 Hz is not an integer multiple of 200 Hz and therefore will not resonate in the same pipe. Similarly, 1000 Hz is the fourth resonant frequency (n = 4), so it will also resonate in the same pipe.

The Lowest-Pitch Tone to Resonate in a Pipe of Length