Which two processes combine inside a raindrop to produce a rainbow?

1. Rainbows are produced by a combination of refraction and reflection. 2. Light refracts as it enters a drop of water, reflects from the back of the drop, then refracts again as it leaves. 3. Because the index of refraction of water varies with wavelength, the two refractions disperse the light into colours. 4. Absorption would destroy the light rather than redirect it, so it cannot build a rainbow. _Source: OpenStax College Physics (CC BY 4.0), Ch 25 "Geometric Optics", section 25.5 Dispersion: The Rainbow and Prisms_