What is Light Dispersion?
Light dispersion is the phenomenon where white light, composed of various colors (wavelengths), splits into its individual spectral colors when it passes through a transparent medium. This occurs because the speed of light, and consequently the refractive index of the medium, is slightly different for each color.
How Does Dispersion Occur?
When light enters a transparent material like glass or water, it slows down. Crucially, shorter wavelengths (e.g., violet and blue) slow down more than longer wavelengths (e.g., red and orange). This difference in speed causes each color to refract, or bend, at a slightly different angle, effectively separating the white light into a visible spectrum.
Everyday Examples of Light Dispersion
The most common natural example is a rainbow, where sunlight is dispersed by water droplets in the atmosphere. Man-made examples include prisms, which are specifically designed to demonstrate how white light can be separated into the colors of the spectrum: red, orange, yellow, green, blue, indigo, and violet.
Importance and Applications
Understanding light dispersion is vital in fields like optics and astronomy. It's crucial in designing optical instruments like telescopes and cameras to correct for chromatic aberration (where different colors focus at different points). Dispersion is also fundamental to spectroscopy, which analyzes the composition of materials by studying how they absorb or emit different wavelengths of light.