Question

When white light is refracted and dispersed, what determines how wide it is gonna be dispersed?

Is it the difference of refractive index between two materials?

And if so, is it related with how strong each colors (red, orange ...) are?

Answer 1

Solution :

For better understanding, imagine that white ray passes through a prism. Initially, it refracts and disperses into the constituent colors of different wavelengths, traveling at different speeds because each wavelength will be refracted slightly at different angles. Thus, refractive index is influenced by the wavelength of light.

Now, Snell's law says that refractive index of prism material depends on angle of refraction of light in a prism. As we already know that refractive index is a function of wavelength of light, angle of refraction of light will also be a function of wavelength of light. This causes angular dispersion which means it results in angular separation of colors.

Refraction indices for most materials like glass, prism, etc decrease with increasing wavelength. That is,