Wave

1
Wave

• Classification
• material Mechanical vs EM
• direction Transverse vs Longitudinal
• energy Travelling vs Stationary
• Wave function
• y A sin wt , y A sin kx y A sin
  (wt - kx)
• 3. Wave equation v fl
• 4. Superposition Formation of stationary wave

F.7 Waves 2
2
Wave 2

• How to show a wave propagating in 2D plane
  wavefront
• 2. Huygens Principle
• 3. Apply Huygens principle to explain the wave
  propagation during
• (a) Reflection
• (b) Refraction

F.7 Waves 2
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Wavefront
F.7 Waves 2
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Wavefront
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Wavefront
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Wavefront
WHY propagate like this?
F.7 Waves 2
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Huygens Principle
Secondary wavefront
Remark The wave goes FORWARD only as assumption
has to be made that the amplitude of the
secondary wavelets varies from a maximum in the
direction of travel of the wave to zero in the
opposite direction.
Secondary wavelet
F.7 Waves 2
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Huygens Principle
Every point on a wavefront may be regarded as a
source of secondary spherical wavelets which
spread out with the wave velocity. The new wave
wavefront is the envelope of these secondary
wavelets, i.e. the surface which touches all the
waves.
F.7 Waves 2
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Huygens Principle
http//www.walter-fendt.de/ph14e/huygenspr.htm
http//www.phy.ntnu.edu.tw/ntnujava/viewtopic.php?
t32
F.7 Waves 2
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Huygens Principle
F.7 Waves 2