Ch12 (2)
- 1. Chapter 12 Waves and Sound
- 2. Ch12.1 Properties of sound
- 3. Compression Rarefaction Simple sinusoidal (sin) vibration– pure tone
- 4. 疏 密 Wave-front surface 波前
- 7. Wave in time domain and space domain 空間 位置 z 時間 z=0
- 8. Compression Rarefaction Intensity Frequency Simple sinusoidal (sin) vibration– pure tone Speed of sound at 20℃, in air 3.3×10 4 cm/sec in water 1.4×10 5 cm/sec Total pressure P P a : ambient air pressure P o : maximum pressure change due to the sound wave Intensity I ~ I : amount of energy transmitted by a sinusoidal sound wave per unit time through each unit area ⊥ the direction of sound propagation ρ: density of medium
- 9. Ch12.2 Some properties of waves Ch12.2.1 Reflection and refraction
- 10. Ch12.2.2 Interference In phase Constructive interference Out of phase Deconstructive interference R=A+B Same frequency
- 11. Standing wave
- 12. close open
- 13. Standing wave Resonant frequency Ch12.2.3 Diffraction
- 14. Ch12.3 Hearing and Ear
- 15. Figures from Urone, College physics Also see Text on p175
- 16. Ch 12.3.1Performance of the Ear Loudness, Pitch, Quality cps cycle per second frequency = + + +
- 17. frequency/ pitch
- 18. C D E F G A B C ’ Do Re Mi Fa Sol La Ti Do 中央 C f C =256Hz 中央 C 之上的 A f A =440Hz
- 19. Ch12.3.3 Intensity and Loudness For human ear Threshold of hearing 10 -16 W/cm 2 , at 3000Hz Threshold of pain 10 -4 W/cm 2 Ex 12-3
- 20. Also see Text on p175 Resonance at 3000Hz, Pressure is increased by another factor of 2 . Mechanical Advantage MA
- 21. Ch 12.4 Bats and Echoes Ex 12-6
- 22. Ch 12.5 Sound produced by animal Ch 12.6 Acoustic Trap Rattlesnake Vocal cord
- 23. Ch 12.7 Clinical uses of Sound Ch12-8 Ultrasonic Wave
- 26. Car moving wavefront profile change
- 27. Car moving wavefront profile change 右邊的人聽到的 :
- 28. Car stop wavefront profile did not change 右邊的人聽到的 :
- 29. 利用超音波及都卜勒效應 量測生物體內液體流速 Urone, College Physics Ex16.7 A diagnostic ultrasound echo is reflected from moving blood and returns with a frequency 500Hz higher than its original 2MHz.The speed of the ultrasound is 1540m/s. (a)What is the velocity of the blood? (b) What frequency does the blood receive?
- 30. Self-practice Exercise 12-3, 12-6, 12-8