UPSC One
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2016 · Q37

In total internal reflection, the light travels from

General KnowledgePhysics
  1. Ararer to denser medium and it occurs with no loss of intensity
  2. Bdenser to rarer medium and it occurs with no loss of intensity
  3. Crarer to denser medium and it occurs with loss of intensity
  4. Ddenser to rarer medium and it occurs with loss of intensity

Explanation

Total internal reflection occurs when light travels from a denser to a rarer medium at an angle exceeding the critical angle; the reflection is then total, occurring with virtually no loss of intensity (unlike partial reflection/refraction). The rarer-to-denser options are wrong because TIR is impossible in that direction.