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Question
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.
Solution
`μ=1/sinC .....(i)`
where
C = Critical angle of medium
μ = Refractive index of the medium
Also,
`μ=c/ν .....(ii)`
`c/ν=1/sinC`
`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.
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