Twinkling of stars is due to atmospheric

(a) dispersion of light by water droplets

(b) refraction of light by different layers of varying refractive indices

(c) scattering of light by dust particles

(d) internal reflection of light by clouds



  • The different atmospheric layers have varying optical densities (refractive indices). 
  • This results in star-light undergoing refraction multiple times before it reaches our eyes. 
  • So a star appears to change its position (twinkle) to the human eye because of atmospheric refraction. 

Why do stars twinkle-01.jpg

So, the correct answer is (b)

  1. Class 10
  2. Chapter 11 Class 10 - Human Eye and Colourful World (Term 1)

About the Author

CA Maninder Singh's photo - Founder at Teachoo
CA Maninder Singh
CA Maninder Singh is a Chartered Accountant for the past 11 years and a teacher from the past 11 years. He teaches Science, Accounts and English at Teachoo