Physics of Rainbow Formation
Question
Rainbow is produced when sunlight falls on drops of rain. Which of the following physical phenomena are responsible for this?
Select the correct answer using the codes given below.
- 1.
Dispersion
- 2.
Refraction
- 3.
Internal reflection
Options
1 and 2 only
2 and 3 only
1 and 3 only
1, 2 and 3
Explanation
Rainbow formation involves all three optical phenomena: (1) Dispersion occurs when white sunlight enters the raindrop and is separated into its constituent colors (wavelengths) due to the refractive index varying with wavelength. (2) Refraction happens twice—once when light enters the raindrop and once when it exits—bending the light rays as they pass through the curved surface of the water droplet. (3) Internal reflection occurs when light rays hit the back surface of the raindrop and reflect internally before exiting. The complete rainbow formation process requires: sunlight → refraction entering → dispersion into colors → internal reflection at the back → refraction exiting → observer's eye. All three phenomena work together sequentially to create the visible spectrum of the rainbow. This is a comprehensive optical phenomenon demonstrating multiple light behaviors.
Answer: (d).
Question details
Year
2014
Paper
GS Paper 1
Question
Q90
Subject
Science & Technology
Sub-topic
Physics - Optics and Light
Type
Statement-based
Difficulty
Medium
Nature
Static
Source hint
Physics - Optics and Light Phenomena
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