What is the Reason for the Spectrum of Color in Compact Disc?

Answer: The spectrum of color in the compact disc is due to the constructive and destructive interference of light.

When two or more than two lights who possess the same frequency, same amplitude, and same wavelength meet in a medium that phenomenon is known as interference of light. The constructive interference takes place in bright fringe and waves of light reinforce each other whereas the destructive interference occurs in dark fringe where waves of light cancel the effects of each other. In 1801, Thomas Young demonstrated the interference of lights in from two sources.

Summary:

What is the Reason for the Spectrum of Color in Compact Disc?

The spectrum of color in the compact disc is due to destructive and constructive interference of the light.