The phenomenon where white light splits into its constituent colors upon passing through a glass prism is known as the formation of a spectrum.

Prism Spectrum Formation Explained

When light travels from one medium to another (like from air to glass), it bends. This bending is called refraction. A glass prism causes light to refract twice: once when entering the prism and again when exiting.

Understanding Light Dispersion

White light is actually a mixture of different colors (like red, orange, yellow, green, blue, indigo, violet). Each color has a different wavelength.

• The amount light bends (refracts) depends on its wavelength.
• Glass causes shorter wavelengths (like violet light) to bend more than longer wavelengths (like red light).
• This difference in bending for each color causes the white light to separate into its individual colors, forming a spectrum.

This effect, where the refractive index of a material varies with the wavelength of light, causing light to split into its constituent colors, is called Dispersion.

Why Other Options Are Incorrect

• Scattering: This involves light bouncing off particles in random directions, not splitting colors predictably.
• Refraction: While refraction occurs, it is the *differential* refraction (varying amounts of bending for each color) that causes the spectrum. Dispersion is the specific term for this color separation.
• Reflection: This is when light bounces off a surface, which doesn't create a spectrum from a prism.

Therefore, the formation of a spectrum by a glass prism is a direct result of Dispersion.