Which phenomenon causes white light to separate into spectral colors?

Which phenomenon causes white light to separate into spectral colors?

• A. Luminescence
• B. Brightness
• C. Luster
• D. Dispersion

Answer: (D)

Dispersion is the phenomenon that makes white light split into colors. When light passes through a prism, different wavelengths bend by different amounts because the refractive index depends on wavelength. Shorter wavelengths (violet, blue) bend more than longer wavelengths (red), so the light spreads out into a spectrum. Luminescence would involve light emission from a material, brightness refers to overall light intensity, and luster describes the surface shine—none of these explain the separation of white light into colors like dispersion does.

Dispersion is the phenomenon that makes white light split into colors. When light passes through a prism, different wavelengths bend by different amounts because the refractive index depends on wavelength. Shorter wavelengths (violet, blue) bend more than longer wavelengths (red), so the light spreads out into a spectrum. Luminescence would involve light emission from a material, brightness refers to overall light intensity, and luster describes the surface shine—none of these explain the separation of white light into colors like dispersion does.