BIO Waves on vocal cords. In the larynx, sound is produced by the vibration of the vocal cords. The diagram in Figure 12.44 is a cross section of the vocal tract at one instant in time. Air flows upward (in the +z direction) through the vocal tract, causing a transverse wave to propagate vertically upward along the surface of the vocal cords. In a typical adult male, the thickness of the vocal cords in the direction of airflow is d = 2.0 mm. High-speed photography shows that for a frequency of vibration of f = 125 Hz, the wave along the surface of the vocal cords travels upward at a speed of u = 375 cm/s. Take t to be time, z to be displacement in the + z direction, and λ to be wavelength. Figure 12.44 Problems 72–74. 74. The wave speed is measured for different vibration frequencies. A graph of the wave speed as a function of frequency ( Fig. 12.45 ) indicates that as the frequency increases, the wavelength A. increases. B. decreases. C. doesn’t change. D. becomes undefined. Figure 12.45 Problem 74.
BIO Waves on vocal cords. In the larynx, sound is produced by the vibration of the vocal cords. The diagram in Figure 12.44 is a cross section of the vocal tract at one instant in time. Air flows upward (in the +z direction) through the vocal tract, causing a transverse wave to propagate vertically upward along the surface of the vocal cords. In a typical adult male, the thickness of the vocal cords in the direction of airflow is d = 2.0 mm. High-speed photography shows that for a frequency of vibration of f = 125 Hz, the wave along the surface of the vocal cords travels upward at a speed of u = 375 cm/s. Take t to be time, z to be displacement in the + z direction, and λ to be wavelength. Figure 12.44 Problems 72–74. 74. The wave speed is measured for different vibration frequencies. A graph of the wave speed as a function of frequency ( Fig. 12.45 ) indicates that as the frequency increases, the wavelength A. increases. B. decreases. C. doesn’t change. D. becomes undefined. Figure 12.45 Problem 74.
BIO Waves on vocal cords. In the larynx, sound is produced by the vibration of the vocal cords. The diagram in Figure 12.44 is a cross section of the vocal tract at one instant in time. Air flows upward (in the +z direction) through the vocal tract, causing a transverse wave to propagate vertically upward along the surface of the vocal cords. In a typical adult male, the thickness of the vocal cords in the direction of airflow is d = 2.0 mm. High-speed photography shows that for a frequency of vibration of f = 125 Hz, the wave along the surface of the vocal cords travels upward at a speed of u = 375 cm/s. Take t to be time, z to be displacement in the + z direction, and λ to be wavelength.
Figure 12.44 Problems 72–74.
74. The wave speed is measured for different vibration frequencies. A graph of the wave speed as a function of frequency (Fig. 12.45) indicates that as the frequency increases, the wavelength
A sound wave has an intensity level of 121.3 dB in air. The density of air at 20.0°C is ρ = 1.20 kg/m3 (see Table 9.1). The speed of sound in air at 20.0°C is v = 343 m/s (see Table 12.1).
What is the pressure amplitude of the wave?
Male Rana catesbeiana bullfrogs are known for their loud mating call.The call is emitted not by the frog’s mouth but by its eardrums, which lie on the surface of the head. And, surprisingly, the sound has nothing to do with the frog’s inflated throat. If the emitted sound has a frequency of 260 Hz and a sound level of 85 dB (near the eardrum), what is the amplitude of the eardrum’s oscillation? The air density is 1.21 kg/m3.
Sound is detected when a sound wave causes the eardrum to vibrate.
Typically, the diameter of the eardrum is about 8.4 mm in humans. When
someone speaks to you in a normal tone of voice, the sound intensity at your
ear is approximately 1.0 × 10-6 W/m².
What is the power delivered to your eardrum?
Express your answer in watts.
P =
17 ΑΣΦ
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W
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Wave Speed on a String - Tension Force, Intensity, Power, Amplitude, Frequency - Inverse Square Law; Author: The Organic Chemistry Tutor;https://www.youtube.com/watch?v=vEzftaDL7fM;License: Standard YouTube License, CC-BY