Exam-style question
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Which of the following best describes the critical angle in optical fibres?.
- A.The angle at which light is completely absorbed.
- B.The angle of incidence that results in a refracted angle of 90 degrees.
- C.The angle at which light can no longer pass through the fibre.
- D.The angle at which light exits the fibre.
Model answer
What a good answer should say
- The angle of incidence that results in a refracted angle of 90 degrees.
Explanation
Why this works
The critical angle is defined as the angle of incidence beyond which light cannot pass through the boundary and is instead reflected back into the medium, occurring at a refracted angle of 90 degrees.
Common mistake
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