Exam-style question
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What is the critical angle for light traveling from glass (n = 1.5) to air (n = 1.0)?.
- A.41.8 degrees
- B.48.6 degrees
- C.60.0 degrees
- D.90.0 degrees
Model answer
What a good answer should say
- 41.8 degrees
Explanation
Why this works
Using the formula for critical angle, θc = sin⁻¹(n2/n1). Substituting gives θc = sin⁻¹(1.0/1.5) = 41.8 degrees.
This shows the angle at which total internal reflection occurs.
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