Total Internal Reflection
A ray of light is incident at a glass-water interface at an angle , it emerges finally parallel to the surface of water, then the value of the refractive index of glass is
refractive index of water

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Answer: (c)
- Snell's law gives constant along the whole path.
- Glass to water to air: .
- The ray finally grazes the water surface, so . The value of cancels out.
- . So the answer is (c).