Wave Motion and Terms

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Wave Motion and Terms

• A wave is an energy disturbance.
• Terms used to describe parts of a wave.

• Amplitude the distance from equilibrium to the
  maximum
  displacement of the wave

• Wavelength, ? the distance between
  corresponding points on
  a wave

• Frequency, f the number of wave disturbances
  that occur each
  second

• Wave speed, v the speed of the wave v ?f

l
A
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Wave Stuff

• Wavelength is the number of meters needed for
• a wave to repeat itself.
• The maximum departure of a wave from its
• equilibrium state is called its amplitude.
• The number of wave crests passing any given
• point per unit time is called the waves
  frequency.
• Period is 1/frequency

Lets Compare
Direction of motion
Note how frequency 1/wavelength
Direction of motion
Wavelength x frequency speed Where speed is c
speed of light
C ? f
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Electromagnetic Radiation it comes from
1. Atomic transitions
2 sources
Figure 4.10a
2. Shake, rattle roll ??
(moving charged particles)
Figure 3.6c
(or rotating or vibrating ones)
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QuestionElectromagnetic radiation wave or
particle?

• Its Both !
• Depending on how you measure it, radiation can
• act like a wave

which has oscillating electric and magnetic fields
http//www.phy.ntnu.edu.tw/java/emWave/emWave.html

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0r like a particle
http//physics.uwstout.edu/physapplets/javapm/java
/atomphoton/index.html
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Electromagnetic Spectrum
The full frequency range of all electromagnetic
waves
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Electromagnetic Spectrum from our perspective