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JEE Main 2004 (AIEEE) · Total Internal Reflection

Total Internal Reflection question from JEE Main 2004 (AIEEE)

Q58JEE Main 2004 · AIEEEMedium

Total Internal Reflection

A light ray is incident perpendicularly to one face of a 90∘90^\circ prism and is totally internally reflected at the glass-air interface. If the angle of reflection is 45∘45^\circ, we conclude that the refractive index nn

Figure

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Answer: (b)

  1. The ray enters normally and meets the hypotenuse at 45∘45^\circ.
  2. TIR needs 45∘>C45^\circ > C: sin⁡45∘>1n\sin45^\circ > \frac{1}{n}.
  3. n>2n > \sqrt{2}. So the answer is (b).
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