Visible light is incident perpendicularly on a grating with 340 rulings/mm. 679 is the longest wavelength that can be seen in the m = 4 diffraction.
Waves spreading outward around obstructions is known as diffraction. Sound, electromagnetic radiation like light, X-rays, and gamma rays, as well as very small moving particles like atoms, neutrons, and electrons that exhibit wavelike qualities all exhibit diffraction.
Diffraction's effects can frequently be observed in daily life. The most spectacular diffraction examples include light, such as when a CD or DVD's tightly spaced tracks create the well-known rainbow pattern when viewed from different angles. Waves bend around gaps and barriers due to diffraction.
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