18. Waves & Sound

BIO Deep-sea divers often breathe a mixture of helium and oxygen to avoid getting the 'bends' from breathing high-pressure nitrogen. The helium has the side effect of making the divers' voices sound odd. Although your vocal tract can be roughly described as an open-closed tube, the way you hold your mouth and position your lips greatly affects the standing-wave frequencies of the vocal tract. This is what allows different vowels to sound different. The 'ee' sound is made by shaping your vocal tract to have standing-wave frequencies at, normally, 270 Hz and 2300 Hz. What will these frequencies be for a helium-oxygen mixture in which the speed of sound at body temperature is 750m/s ? The speed of sound in air at body temperature is 350m/s .

The fundamental frequency of a pipe that is open at both ends is 524 Hz. If one end is now closed, find the wavelength

The fundamental frequency of your closed organ pipe is 200 Hz. The second overtone of this pipe has the same frequency as the 3^rd harmonic of an open pipe. What is the length of this open pipe?

Standing sound waves are produced in a pipe that is 1.20 m long. For the fundamental and first two overtones, determine the locations along the pipe (measured from the left end) of the displacement nodes and the pressure nodes if the pipe is closed at the left end and open at the right end.

Standing sound waves are produced in a pipe that is 1.20 m long. For the fundamental and first two overtones, determine the locations along the pipe (measured from the left end) of the displacement nodes and the pressure nodes if (a) the pipe is open at both ends

A bass clarinet can be modeled as a 120-cm-long open-closed tube. A bass clarinet player starts playing in a 20° C room, but soon the air inside the clarinet warms to where the speed of sound is 352m/s . Does the fundamental frequency increase or decrease? By how much?

(II) An unfingered guitar string is 0.68 m long and is tuned to play E above middle C (330 Hz). What are the frequency and wavelength of the sound wave produced in air at 22°C by this fingered string?

The fundamental frequency of a pipe that is open at both ends is 524 Hz. How long is this pipe? If one end is now closed

A 170-cm-long open-closed tube has a standing sound wave at 250 Hz on a day when the speed of sound is 340m/s . How many pressure antinodes are there, and how far is each from the open end of the tube?

The vibrating portion of an A-string on a particular violin measures 32 cm, and its fundamental frequency is precisely 440 Hz. How far from the end of the string should the violinist place a finger so that the string plays a note at 588 Hz?

An oscillator vibrating at 1250 Hz produces a sound wave that travels through an ideal gas at 325 m/s when the gas temperature is 22.0°C. For a certain experiment, you need to have the same oscillator produce sound of wavelength 28.5 cm in this gas. What should the gas temperature be to achieve this wavelength?

A 280 Hz sound wave is directed into one end of the trombone slide seen in FIGURE P17.55. A microphone is placed at the other end to record the intensity of sound waves that are transmitted through the tube. The straight sides of the slide are 80 cm in length and 10 cm apart with a semicircular bend at the end. For what slide extensions s will the microphone detect a maximum of sound intensity?

A flutist assembles her flute in a room where the speed of sound is 342 m/s. When she plays the note A, it is in perfect tune with a 440 Hz tuning fork. After a few minutes, the air inside her flute has warmed to where the speed of sound is 346 m/s. How far does she need to extend the 'tuning joint' of her flute to be in tune with the tuning fork?

An unfingered guitar string is 0.68 m long and is tuned to play E above middle C (330 Hz). How far from the end of this string must a fret (and your finger, Fig. 16–8) be placed to play A above middle C (440 Hz)?