Light passes from glass () into air. Which statement about the critical angle is correct?
Answer and explanation
Correct answer: B. total internal reflection occurs for angles above about
- Step 1: Total internal reflection needs light to go from the denser to the less dense medium, as here. Step 2. The critical angle satisfies , so , and larger angles are totally reflected. **Answer: above about . Why not the others:** Smaller angles refract out of the glass, a critical angle exists for glass to air, and is the angle for equal indices.
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