You are given kerosene, turpentine and water. In which of these does the light travel fastest? Use the information given in Table 10.3

Table 10.3 NCERT - Refractive Index of Some Media.jpg

Answer

We know that,

Refractive index of the medium = Speed of light in air / Speed of light in the medium 

 

Therefore,

Speed of light of the medium = Speed of light in air / Refractive index in the medium 

 

Since Speed of light in air is always constant

 

Hence,

Speed of light in the medium = Constant/ Refractive index of the medium

 

Hence, we can say that

Lower refractive index of the medium, the higher is the speed of light.

 

The refractive index of

  • Kerosene is 1.44
  • Turpentine is 1.47
  • Water is 1.33

 

Since the refractive index of water is the lowest among the three, 

Speed of light in water would be higher than that in kerosene and turpentine.

  1. Class 10
  2. Chapter 10 Class 10 - Light - Reflection and Refraction

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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