Exam-style question
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If the speed of light in a vacuum is 3.0 x 10^8 m/s and the speed of light in glass is 2.0 x 10^8 m/s, what is the refractive index of glass?.
- A.1.5
- B.0.67
- C.1.0
- D.2.0
Model answer
What a good answer should say
- 1.5
Explanation
Why this works
The formula for refractive index is n = c / v. Substituting gives n = (3.0 x 10^8 m/s) / (2.0 x 10^8 m/s) = 1.5.
This indicates how light slows down in different media.
Common mistake
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