Question 10 - MCQs from NCERT Exemplar - Chapter 11 Class 10 - Human Eye and Colourful World

Which of the following phenomena contributes significantly to the reddish appearance of the sun at sunrise or sunset?

(a) Dispersion of light

(b) Scattering of light

(c) Total internal reflection of light

(d) Reflection of light from the earth

Answer

The sun appears to be red at sunrise and sunset because Earth’s atmosphere scatters the colours of the white light from the sun.

The colours we see are the ones left after the scattering. The phenomenon is called Rayleigh Scattering. 

• Rayleigh scattering is inversely dependent upon wavelength.

• The colours with the smaller wavelengths are scattered more. 
• At sunrise and sunset ,  violet, blue , green, and yellow colors are scattered through the atmosphere. 
• The light has to travel a longer distance , so more colors are scattered . 
• The red light reaching our eyes makes the sun appear red.  

So, the correct answer is (b)