A rainbow is formed by:
ARefraction + total internal reflection + dispersion in water drops
BReflection of light by clouds
CDiffraction by raindrops
DPolarisation by atmospheric dust
Answer & Solution
Correct answer: A. Refraction + total internal reflection + dispersion in water drops
1. Sunlight enters a spherical raindrop, REFRACTS (dispersion separates colours).
2. It undergoes TIR at the back of the drop.
3. Then refracts again as it leaves — separating colours further.
4. Net result: a circular band of colours, red on the outer edge and violet inside.
_Source: NCERT Class 10 Science Ch 10 §10.4 Atmospheric Refraction (Rainbow)_
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