How many internal reflections of light take place in the formation of

How many internal reflections of light take place in the formation of primary rainbow ?

0
1
2
More than 2
This question was previously asked in
UPSC CDS-1 – 2021
A primary rainbow is formed when sunlight is dispersed by water droplets. The process involves the sunlight entering a raindrop, undergoing refraction at the front surface, reflecting internally off the back surface, and finally refracting again as it exits the raindrop.
The light path for a primary rainbow within a raindrop includes one internal reflection. The sequence is: refraction (entry) → reflection (internal) → refraction (exit). This single internal reflection, combined with refraction and dispersion, separates the light into its constituent colours, forming the rainbow arc.
A secondary rainbow, which is fainter and appears above the primary bow with reversed colours, is formed by sunlight that undergoes two internal reflections within the raindrops. Higher-order rainbows involving three or more internal reflections are theoretically possible but are rarely observed due to significant loss of light intensity.
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