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Wave Optics

Question
CBSEENPH12038436

A ray of light goes from medium 1 to medium 2. Velocity of light in the two media are c1 and c2 respectively. For an angle of incidence 0 in medium 1, the corresponding angle of refraction in medium 2 is ө/2.
(i)    Which of the two media is optically denser and why?
(ii)    Establish the relationship between ө, c1 and c2.

Solution

Given, 

i) Angle of incidence in medium 1 =  
Angle of refraction in medium 2 =  

Angle of refraction in medium 2 is less than angle of incidence in medium 1. That is, the ray is bending towards the normal. Therefore, medium 2 is optically denser than medium 1. 

ii) Using Snell's law, 
      = 
        =  2 cos 

Also, refractive index  
This implies, 
                   

i.e.,               
which is the required relationship between ө, c1 and c2 .





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