2.3 General Behavior of Waves

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2.3 General Behavior of Waves

1. Reflection
2. Refraction
3. Interference
4. Diffraction

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Reflection
The law of reflection The angle of incidence
The angle of reflection.
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Reflection and Huygenss wavelets
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Parabolic Reflector
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Ellipse
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Whispering Chamber
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Refraction
The bending of a wave as it passes from one
medium to another is called refraction.
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Refraction is due to changes in Wavespeed
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Refraction and Speed of the Wave
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Refraction of wavesIllustrated using Huygenss
wavelets
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Waves at a beach
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Voices travel further at night, than during the
day
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With the wind or Into the wind
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Range of thunder
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Interference

• Interference refers to the combining or addition
  of two similar waves.
• Interference can be destructive, resulting in the
  effective disappearance of the waves, when they
  are out of phase.
• It can be constructive, resulting in the
  enhancement of the waves, when they are in phase.
  

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Destructive Interference
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Constructive Interference
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Quinckes Interference Tube
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Path Length Difference and Interference
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Interference along antinodal and nodal lines
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Noise-canceling headphones utilize destructive
interference
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Diffraction of Sound
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Diffraction
Diffraction is the bending of waves around
obstacles or the edges of an opening in the same
medium. It can be explained using Huygenss
principle. The amount of diffraction depends on
the nature of waves and their wavelength. Sound
waves diffract much more than light
waves. Low-frequency (high-wavelength) sound
waves diffract more than high-frequency
(low-wavelength) light waves.
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Diffraction in Speakers
Small-diameter speakers, called tweeters, are
used to produce high-frequency sound. The small
diameter helps to promote a wider dispersion of
the sound. The amount of bending is depends on
the ratio ?/w, ?
is the wavelength and w is the width of the
opening.