What is a rainbow? Draw a labelled diagram to show its formation.

This answer is grounded directly in Section 10.4 of the chapter: "A rainbow is a natural spectrum appearing in the sky after a rain shower... It is caused by dispersion of sunlight by tiny water droplets, present in the atmosphere. A rainbow is always formed in a direction opposite to that of the Sun. The water droplets act like small prisms. They refract and disperse the incident sunlight, then reflect it internally, and finally refract it again when it comes out of the raindrop. Due to the dispersion of light and internal reflection, different colours reach the observer's eye." The chapter also notes a rainbow can be seen on a sunny day through a waterfall or fountain spray with the Sun behind the observer, reinforcing that both a water-droplet medium and correct sun-observer geometry are required. The embedded diagram mirrors Figure 10.8 ('Rainbow formation') in the chapter, showing the three distinct optical events inside a single raindrop: refraction with dispersion at entry, total internal reflection at the back surface, and a second refraction at exit that sends the separated VIBGYOR colours toward the observer. Line labels are placed at each segment's midpoint, spaced well apart from one another and from the circle outline, so no two labels overlap.