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What frequencies will a 1.80-m-long tube produce in the audible range at 20.0ºC if: (a) The tube is closed at one end?

a) 189 Hz, 567 Hz, 945 Hz, ...
b) 378 Hz, 756 Hz, 1134 Hz, ...
c) 283 Hz, 566 Hz, 849 Hz, ...
d) 525 Hz, 1050 Hz, 1575 Hz, ...

User IGroza
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1 Answer

4 votes

Final answer:

A 1.80-m-long tube closed at one end will produce frequencies of 189 Hz, 567 Hz, and 945 Hz in the audible range at 20.0°C. The correct answer is option A.

Step-by-step explanation:

When a tube is closed at one end, it produces a series of harmonics with only odd multiples of the fundamental frequency present. The formula to calculate the frequencies produced by a closed tube is f = (2n-1)v/4L, where f is the frequency, v is the speed of sound, n is a positive integer representing the mode of resonance, and L is the length of the tube. In this case, the length of the tube is 1.80 m. At 20.0°C, the speed of sound in air is approximately 343 m/s. Using this information, we can calculate the frequencies produced by the tube as follows:

  1. Fundamental frequency (n=1): f = (2(1)-1)(343 m/s)/(4(1.80 m)) = 189.4 Hz
  2. Second harmonic (n=2): f = (2(2)-1)(343 m/s)/(4(1.80 m)) = 567.1 Hz
  3. Third harmonic (n=3): f = (2(3)-1)(343 m/s)/(4(1.80 m)) = 945.7 Hz

Therefore, the frequencies produced by the 1.80-m-long closed tube at 20.0°C are approximately 189 Hz, 567 Hz, and 945 Hz.

User Jason Young
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