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The frequency of a sound is the number of waves that pass a point per unit time. Figure 14.7 A sound wave emanates from a source vibrating at a frequency f, propagates at v, and has a wavelength λ λ . In musical instruments, shorter strings vibrate faster and hence produce sounds at higher pitches.
As an example, for water waves, v w is the speed of a surface wave; for sound, v w is the speed of sound; and for visible light, v w is the speed of light. The amplitude X is completely independent of the speed of propagation v w and depends only on the amount of energy in the wave.
The student should be able to identify and describe the characteristics of amplitude, wavelength and frequency for a sound wave. The student should be able to identify factors effecting (and not effecting) the speed of a sound wave.
The wavelength of a sound is the distance between adjacent identical parts of a wave—for example, between adjacent compressions as illustrated in Figure 17.8. The frequency is the same as that of the source and is the number of waves that pass a point per unit time.
Learn about sound properties such as amplitude, period, frequency, and wavelength on Khan Academy.
Whether the heat transfer from compression to rarefaction is significant depends on how far apart they are—that is, it depends on wavelength. Wavelength, frequency, amplitude, and speed of propagation are important characteristics for sound, as they are for all waves.
There is plenty of confusion about how to measure sound amplitude. Sound intensity is the product of pressure and velocity and reflects the power (energy/time) of the sound wave: Intensity = pressure x velocity = power / area Near the sound source, intensity decreases with the square of the distance from the source. Intensity measures the total ...
