Assertion (A): The refractive index of diamond is  √6 and refractive index of a liquid is √3. If the  light travels from diamond to the liquid, it will be  internally reflected when the angle of incidence is  30°.  

Reason (R): μ =  1 / sinC, where μ is the refractive  index of diamond with respect to liquid.  

Answer  

Explanation: when light travels from denser medium to lesser denser medium then total internal reflection occurs. 

sin C = 1 / n

  • C is the critical angle  
  • n is the refractive index of denser medium (here, diamond).

Therefore, the Refractive index of diamond w.r.t.  liquid  

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Thus, the critical angle is 45 degrees. Therefore, TIR will not take place at 30 °.

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Thus,  

  • Assertion is false
  • Reason is true

So, the correct answer is (d)

Correct option: (d) 

  1. Class 10
  2. Chapter 10 Class 10 - Light - Reflection and Refraction (Term 1)
Class 10
Chapter 10 Class 10 - Light - Reflection and Refraction (Term 1)

About the Author

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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