DIFFRACTION OF WAVES
Any wave of any kind will change direction when it encounters an obstacle. This bending is called “diffraction,” and is most noticeable for longer wavelengths. When the wavelength of a wave is comparable to or smaller than the size of an obstacle or aperture, diffraction is sometimes difficult to detect. When the wavelength of a wave is large compared to the size of an obstacle or aperture, diffraction is so extreme that it may not be evident that an obstacle even existed.





The most simple example of diffraction to analyze to begin with is Thomas Young's Double Slit.


Here we see diffraction, plus superposition, resulting in both constructive and destructive interference.


GRATING
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