16. Superposition
16.2 Diffraction
Diffraction is the bending of a wave around an obstacle or through an opening. The closer the obstacle/opening is to the wave's wavelength, the greater the amount of diffraction. The amount of diffraction decreases as the curvature of the diffracted wavefront decreases and the calm area behind the obstacle/opening increases.
Notice that during the diffraction of plane wavefronts through an opening, neither the frequency nor wavelength change. However, the wave shape changes from plane waves to circular wavefronts.
Depending on the relative size of the opening compared to the wavelength, interference fringes can sometimes be seen within the diffraction pattern.
Notice that during the diffraction of plane wavefronts through an opening, neither the frequency nor wavelength change. However, the wave shape changes from plane waves to circular wavefronts.
- For narrow openings, the center of the opening acts as a point source.
- For wider openings, the edges of the opening act as two VERY DISTANT in-phase point sources. This results in the appearance that the plane wavefront has essentially passed through the opening unchanged, with just a little bit of bending, ir diffraction, on the edges.
Depending on the relative size of the opening compared to the wavelength, interference fringes can sometimes be seen within the diffraction pattern.
16.3 Interference
PhET Wave Interference Simulation
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16.4 Two-source interference patterns
Double slit diffraction experiment | |
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Lab- Interference with a He-Ne Laser
He-Ne laser diffraction interference Lab.pdf | |
File Size: | 197 kb |
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He-Ne laser diffraction lab report.pdf | |
File Size: | 352 kb |
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Multiple-slit diffraction experiment | |
File Size: | 82 kb |
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16.5 Diffraction grating
Revision
16.1 Stationary waves
Speed of sound standing waves.pdf | |
File Size: | 373 kb |
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