# Waves - PowerPoint PPT Presentation

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## Waves

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### Waves Longitudinal and Transverse Waves Transverse Waves on Strings Periodic Waves Reflection and Refraction of Waves Interference and Diffraction – PowerPoint PPT presentation

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Title: Waves

1
Waves
• Longitudinal and Transverse Waves
• Transverse Waves on Strings
• Periodic Waves
• Reflection and Refraction of Waves
• Interference and Diffraction
• Standing Waves on a String

2
??
• ????
• ????
• Mechanical Waves ??
• Electromagnetic Waves ?
• Matter Waves ??
• ??????
• Transverse string wave
• Longitudinal sound wave

3
??(Transverse Wave)
4
??(Longitudinal Wave)
5
?? ? ??
• wavelength frequency

6
???????
• ??(amplitude)
• ??(phase)
• ??(wavelength)
• ???(angular wave number)
• ??(period)
• ???(angular frequency)
• ??(frequency)

7
is used for a wave traveling in the x
direction, and is used for a wave traveling in
the x direction.
is called the wave number.
is called the phase.
Note it would also be valid to use the sine
function in the above description.
8
???? vs ????
9
????(Superposition)
10
??(Reflection)
11
??(Refraction)
12
??(Interference)
13
??(Difraction)
14
??(Standing Waves)
15
???????
• ?????????
• ?????????

16
??
• Sound Waves
• The Speed of Sound
• Amplitude Intensity of Sound Waves
• Standing Sound Waves
• Beats
• The Doppler Effect
• Shock Waves
• Echolocation

17
??
• ???????????????20 Hz ????20,000 Hz.?????,??????
20,000 Hz ?????????????????20 Hz ?????.

18
?????
• ????,??????????????.????,????????????,?????????.??
????,?????????????????,??????????????????.

19
??????
????????
???????????
20
??????
???????????????????????.
21
????????? (0C, 1 atm? )
? ? ?? (m/s)
???? 259
?? 343
?? 972
?? 1284
?? 1450
? 1493
?? 1570
??? 3100
? 5790
??? 6500
22
??????
23
????????Amplitude Intensity
????
??????
24
??(Decibel)
• ????????????????(???)????????( bel ),
???????(??????,?????dB).
• ??????????????????????(?10??)????,???????? 0 dB.

25
?????
• ??????.
• ??????.

26
??????
• ????????????????(??????),?????????????.

27
???? ( ??????? )
28
??????
• ????????????,???????.???????????.

29
???? ( ??????? )
30
????
31
??(Timbre)
• ??????????????????????????????.???????????????????
????.???????????,??????,??????????????(???????????
??).
• ??????????????????(??????)???,?????????????(
Fourier analysis).???,?????????????????,??????????
???( Fourier synthesis).

32
Flute, Oboe, Saxophone
33
?? (Loudness)
• ???????????????,????????.???????3 ?4
kHz?????????,??????10 kHz???800Hz???????????.

34
?????
35
?(Beats)
• ????????(????),??????????,?????.??????????????.
• ????????????,?????15Hz?????????????????15Hz???,??
?????????.
• ??????????????????????.

36
????
????????????
37
????? (Doppler Effect)
• ????????????,?????????????,?????????.
• ??????,??????,??????,??????.

38
(No Transcript)
39
(No Transcript)
40
??????????
• ?????????????,??????????,???????????.

(12-14)
?? ? ??????????,????,???,?????
41
??(Shock Waves)
• ?????????????,?????????????????,?????.????,???????
,????????????.

42
(a)?????????????(b)???????????????????????????,?
??????????????(c)????????????
43
???? (Echolocation)
• ???????????????????????.?????????,???????????.
• ???????????????(sonar),???????????????????????.

44
????????????????????????????,????????????????