The wavelength of light plays a crucial role in its dispersion within a material because the refractive index of most materials varies with wavelength — a property known as dispersion.
How Wavelength Affects Dispersion:
- Shorter Wavelengths Refract More:
Light with shorter wavelengths (like violet and blue) generally experiences a higher refractive index, meaning it slows down more and bends more when entering a material. - Longer Wavelengths Refract Less:
Light with longer wavelengths (like red) encounters a lower refractive index, so it bends less compared to shorter wavelengths. - Resulting in Color Separation:
Since different wavelengths bend by different amounts, they follow different paths inside the material. This separation of paths causes the light to spread into a spectrum of colors, which is dispersion. - Greater Wavelength Difference = More Dispersion:
The wider the range of wavelengths in the incoming light, the more noticeable the dispersion effect will be, especially in materials with strong wavelength-dependent refractive properties. - Material-Specific Behavior:
The exact relationship between refractive index and wavelength differs across materials. For example, flint glass shows more dispersion than crown glass due to a steeper variation in refractive index with wavelength.
In essence, the shorter the wavelength, the greater the bending, which leads to stronger dispersion in a material.