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:
Answer & explanation
Answer: (d) 1, 2 and 3
Each raindrop works like a tiny prism. Sunlight refracts as it enters the drop and splits into colours (dispersion). It then reflects off the back of the drop (internal reflection) and refracts again as it leaves. All three phenomena are involved.
- ✓ 1. Different colours bend by different amounts inside the drop, so white sunlight splits into its component colours. This splitting is dispersion.
- ✓ 2. Light is refracted when it enters the raindrop and refracted again when it leaves.
- ✓ 3. Between the two refractions, the dispersed light reflects from the inner back surface of the drop. This sends it back towards the observer.
- ✗ (a) It leaves out internal reflection, which turns the light back towards the observer.
- ✗ (b) It leaves out dispersion, which produces the colours.
- ✗ (c) It leaves out refraction, which bends the light at both surfaces of the drop.
Remember · Rainbow = refraction + dispersion + internal reflection (then refraction again) in raindrops. It always forms opposite to the Sun.
📘 Read it in NCERT: Class 10 Science, Ch 10 (practise this chapter)
Sources
- NCERT Class 10 · Science, Chapter 10 “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”
Question: UPSC Civil Services (Preliminary) 2013, General Studies Paper I. Explanation: Minimalist IAS, checked 25 Oct 2026 (how we verify). ·
