2.  Depends on relative motion of source and detector  Closer = decr wavelength › Incr pitch › Blue shift  Farther = incr wavelength › Decr pitch › Red shift

3.  EM waves do not require a medium  Speed of light can be different for different observers  One Doppler effect-it depends on the relative speed between the observer and the source  Doppler radar-EM waves are sent out › Change in frequency of the reflected beam relative to the outgoing beam measures speed of clouds and precipitation that reflected the beam

5.  IB text (green) › P.299-300 ex 11.2(a) & (b)  Walker Text (blue) › P.471 # 34, 35, 38, 42, 44, 45, 46, 84

6.  Fixed End › Inverted › 180 o change in phase  Free End › Erect › In Phase

7.  Waves at a discontinuity, or boundary between different media › Part of wave is reflected. › Part of wave is transmitted into the new medium. › The “heavier”, or “more rigid”, or “denser” the second section: the more is reflected & less transmitted

8.  Principle of Superposition › The net effect of two causes is found by adding the individual effects of each cause. › Crest + Crest = one larger crest  Constructive Interference › Crest + Trough = zero displacement  Destructive Interference › Interference need not be complete

9.  Coherent Sources › Same frequency › In phase  Nodes – complete destructive interference  Antinodes – max constructive interference

10.  IB text (green) › P.124 ex 4.5(b) & P.442 ex 18.3  Walker Text (blue) › PP.471-472 #47-49, 51, 53, 55

11.  Two waves moving through a medium simultaneously will interfere › Speed depends on medium › If frequency is correct, interference will result in a waveform which appears to stand still

12. Nodes – points of zero displacement Antinodes – points of maximum displacement Node Antinode

13.  Usually produced by reflected wave interfering with incident wave  From rigid surface › Nodal points @ source & point of reflection  Standing wave does not propagate energy

14.  IB text (green) › P.294 ex 11.1(a)

15.  Resonance › An oscillatory system is driven by a driving force that has a frequency equal to the natural frequency of oscillation of the system › Can be useful or harmful

16.  Resonant standing waves: harmonics › 1 st harmonic: fundamental

17.  Strings › Fixed end reflection = phase change  1 st harmonic: L = ½ λ  2 nd harmonic: L = λ  3 rd harmonic: L = ¾ λ  4 th harmonic: L = 2λ

18.  Laws of Strings › Law of Lengthsf = l ’ f’ l › Law of Diametersf = d ’ f’ d › Law of Tensionsf = √F f’ √F ’ › Law of densitiesf = √D ’ f’ √D

19.  Columns of air (pipes) › Closed end reflection  phase change  Node at the end  Only odd harmonics are present  1 st harmonic: L = ¼ λ  3 rd harmonic: L = ¾ λ  5 th harmonic: L = 5 / 4 λ

20.  Columns of air (pipes) › Open end reflection  No phase change  Antinode at the end  All harmonics are present  1 st harmonic: L = ½ λ  2 nd harmonic: L = λ  3 rd harmonic: L = 3 / 2 λ

21.  IB text (green) › P.297 ex 11.1(b)  Walker Text (blue) › P.472 #57-59, 60, 63-65, 68