ReasoningModerate2 marks
A ray of light enters a rectangular glass slab submerged in water at an angle of incidence 55°. Does this ray undergo total internal reflection when it moves from water to glass? Justify your answer. (The critical angle for glass–water interface is 54°)
Topic: Conditions for total internal reflection
Question wording verified against source paper
Answer
Exam answer
No, it will not undergo total internal reflection.
Explanation
The ray travels from water (optically rarer) to glass (optically denser). Total internal reflection can occur only from a denser to a rarer medium, so the 54° critical angle is not applicable in this direction.
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