Question
A ray of light travelling in a transparent medium of refractive index μ falls, on a surface separating the medium from the air at an angle of incidence of 45o. For which of the following value of μ the ray can undergo total internal reflection?
-
μ =1.33
-
μ = 1.40
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μ = 1.50
-
μ = 1.25
Solution
C.
μ = 1.50
For total internal reflection
i > c
⇒ sin i > sin c
⇒ sin 45o > 1/ μ
μ > 21/2
μ > 1.4
