Class 10
Chapter 11 Class 10 - Human Eye and Colourful World

Assertion (A): Sunlight reaches us without  dispersion in the form of white light and not as its  components. 

Reason (R): Dispersion takes place due to variation  of refractive index for different wavelengths but  in vacuum the speed of light is independent of  wavelength and hence vacuum is a non-dispersive  medium. 




For Assertion

  • Dispersion only occurs after the sunlight enters the atmosphere at a minor rate. 
  • So sunlight reaches us without dispersion in the form of white light and not as its components. 
  • Therefore, the assertion is true.


For reasoning

  • This happens because before entering the atmosphere, sunlight passes through vacuum  
  • In vacuum , light does not disperse
  • In vacuum, all colours travel with the same speed.  

Thus, Reasoning is also true. 



  • Assertion is True
  • Reasoning is True
  • And the reason is the correct explanation for the assertion.

Correct option: (a)

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CA Maninder Singh is a Chartered Accountant for the past 14 years and a teacher from the past 18 years. He teaches Science, Economics, Accounting and English at Teachoo