Question

What phenomenon of light is responsible for the multicolored appearance of a Compact Disc $(CD)$?

Answer 1

Hint : To solve these types of questions we must have a knowledge about the different phenomena of light such as diffraction, refraction, reflection, etc. When we know about these processes then we would be able to choose the correct phenomenon involved with a particular fact.

Complete step-by-step solution:
The phenomenon of light is responsible for the multicolored appearance of a Compact Disc $(CD)$ is diffraction. The multicolored appearance of a Compact Disc which appears to be a rainbow is formed when light rays hit the Compact Disc. We know that a Compact Disc is composed of closely packed tracks which behave as a diffraction grating. Now when the light rays fall on these closely packed tracks, it gets diffracted thereby giving a multicolored appearance to the Compact Discs. Diffraction can be defined as the bending of light when it passes around a sharp corner of some obstacle or passes through an opening. Diffraction is possible only when the wavelength of the light rays is comparable to the size of the slit through which the light rays pass. The other important condition for the diffraction phenomenon to occur is that the light rays that are incident on the Compact Disc must be monochromatic in nature.

Note: In this question, we were asked about the main phenomenon that is responsible for multicolored appearance of a Compact Disc $(CD)$, hence our answer was diffraction. It must be noted that there are other phenomena that also assist diffraction such as transmission and refraction of light rays.