Exam-style question
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What is the unit of optical power?.
- A.Watt
- B.Joule
- C.Diopter
- D.Newton
Model answer
What a good answer should say
- Diopter
Explanation
Why this works
Optical power is measured in diopters (D), which is defined as the reciprocal of the focal length in meters. This unit indicates the lens's ability to converge or diverge light.
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