A transparent block A having refractive index μ = 1.25 is surrounded by another medium of refractive index μ = 1.0 as shown in figure. A light ray is incident on the flat face of the block with incide

Question

A transparent block A having refractive index $μ = 1.25$ is surrounded by another medium of refractive index $μ = 1.0$ as shown in figure. A light ray is incident on the flat face of the block with incident angle $θ$ as shown in figure. What is the maximum value of $θ$ for which light suffers total internal reflection at the top surface of the block?

TestHub · Accepted Answer

​ r + θ C ​ = 9 0 ∘ μ 1 ​ sin θ = μ 2 ​ sin r sin θ = μ 1 ​ μ 2 ​ ​ sin ( 90 − θ C ​ ) sin θ = μ 1 ​ μ 2 ​ ​ cos θ C ​ sin θ C ​ = μ 2 ​ μ 1 ​ ​ ​ ​ sin θ = μ 1 ​ μ 2 ​ ​ 1 − μ 2 2 ​ μ 1 2 ​ ​ ​ sin θ = μ 1 2 ​ μ 2 2 ​ − μ 1 2 ​ ​ ​ = 1 16 25 ​ − 1 ​ ​ sin θ = 4 3 ​ θ = sin − 1 ( 4 3 ​ ) ​

Physics - Geometrical Optics Question with Solution | TestHub

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