A pipe is closed at one end. A speaker attached to an adjustable signal source is placed very near the open end. The volume of the speaker is set very low so that the sound can barely be heard. However, as the frequency of the source is adjusted it is found that at certain frequencies a loud sound is produced.
(a) Why is a loud sound produced and why is it only produced at certain frequencies?
(b) Most speakers have a range of frequencies that they work well within. This is a small speaker and like most small speakers it does not work well at low frequencies. So the tube can’t be tested at very low frequencies. It is found that a loud sound is produced at frequencies of 735 Hz, 1225 Hz, and 1715 Hz. What is the fundamental frequency of this tube? Which harmonics are these three that have been observed?
(c) How long must the tube be? The temperature in the room is 20? C.
(d) Suppose the closed end of the tube is sliced off so that the tube is the same length, but is now open at both ends. What frequencies will produce a loud sound now?