Advertisement Remove all ads

Calculate the Speed of Light in a Medium Whose Critical Angle is 45° - Physics

Calculate the speed of light in a medium whose critical angle is 45°. Does critical angle for a given pair of media depend on the wavelength of incident light ? Give reason.

Advertisement Remove all ads

Solution

 
(i) According to Snell's Law, we have

`μ=1/sinC                  .....(i)`



where

 C = Critical angle of medium
  μ = Refractive index of the medium

Also,

`μ=c/ν                   .....(ii)`

 
where c=Speed of light in vacuum
  
ν=Speed of light in medium
From (i) and (ii), we have

`c/ν=1/sinC`

v=sinC×c
v=sin45×3×108
v=2.12×108
Therefore, speed of light in the medium is 2.12×108 m s1.
(ii) We know that the critical angle of the medium depends on its refractive index which is given by

`C=sin−1(1/μ)`


The refractive index μ of a medium is inversely proportional to the wavelength of incident light. So, the critical angle of the medium also depends upon the wavelength of incident light.
 
Concept: Snell’s Law
  Is there an error in this question or solution?
Advertisement Remove all ads
Advertisement Remove all ads
Advertisement Remove all ads
Share
Notifications

View all notifications


      Forgot password?
View in app×