Q. Consider the following phenomena observed when viewing a compact disc (CD) under sunlight:

1. Reflection
2. Interference
3. Diffraction

Which of the above phenomena are responsible for the appearance of rainbow colors on a CD surface?
Answer: 1, 2 and 3
Notes: Rainbow colors on a CD result from a combination of reflection, interference, and diffraction of light. The microscopic grooves on the CD's surface cause incident light to reflect at different angles, producing constructive and destructive interference patterns characteristic of diffraction gratings, resulting in the visible spectrum of colors.