Rainbow is produced when sunlight falls on drops of rain. Which of the following physical phenomena are responsible for this? 1. Dispersion 2. Refraction 3. Internal reflection Select the correct answer using the codes given below.

The formation of a rainbow is a complex optical phenomenon involving three distinct physical processes. When sunlight enters a spherical raindrop, it first undergoes refraction as it moves from air to the denser medium of water [1]. During this entry, dispersion occurs because different wavelengths of light travel at different speeds in water, causing the white light to split into its constituent colors [1]. The light then hits the back surface of the droplet and undergoes internal reflection, which directs the light back toward the observer [1]. While some sources refer to this as total internal reflection, it is technically a partial internal reflection as some light still escapes through the back. Finally, the light refracts again as it exits the droplet, further separating the colors into the visible arc [1]. Thus, dispersion, refraction, and internal reflection are all essential to the process.

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 10: The Human Eye and the Colourful World > Activity 10.2 > p. 167