NCERT Example 9.5 - Ray Optics and Optical Instruments
Question: Figure shows a cross-section of a light pipe made of glass fibre with outer cladding. For light incident at A at angle θ = 45° with axis, find the largest value of refractive index of cladding for which light does not leak. Core μ = 1.68.
Answer: Largest cladding refractive index ≈ **1.414** (so that TIR just begins).
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