Dispersion of light
Dispersion (of light) is what we call phenomena that arise as a result of the dependence of the refractive index on the wavelength, i.e. phenomena in which white light is split into individual colors during the passage of light through a substance. The cause of dispersion is the dependence of the phase velocity of the light wave propagation on its wavelength (v = f (λ)) when passing through a material environment.
Dispersion of light is the breakdown of electromagnetic radiation into components at different wavelengths.
- c = phase velocity in vacuum, ε = permittivity of vacuum, μ = vacuum magnetic permeability
This relationship shows that the speed of light in a vacuum is the same for all wavelengths, and light dispersion does not occur in a vacuum.
Dispersion of substances – quantity determining the rate of change of the refractive index (n =c / v) depending on the wavelength (derivative of the refractive index according to the wavelength). In transparent media, the refractive index increases with decreasing λ. If this quantity is < 0 = normal dispersion, > 0 = abnormal dispersion.
Division[edit | edit source]
- normal dispersion,
- chromatic dispersion,
- anomalous dispersion.
The most common dispersion is a rainbow. Sunlight falls on a falling raindrop, the ray is refracted into the drop, and some of the light reflects off the inner surface of the drop and then refracts outward. The first refraction causes the light to split into a spectrum. The second quarry enlarges. Light is refracted in large numbers. Red comes from drops above and purple below. If the Sun is higher above the horizon, the rainbow cannot be seen.
A 2nd order rainbow has an angle of 53° and the color order is reversed.
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External links[edit | edit source]
Sources[edit | edit source]
- KUBATOVA, Senta. Biofot [online]. [cit. 2011-01-31]. <https://uloz.to/!CM6zAi6z/biofot-doc>.
