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Can the absolute refractive index of a medium be less than one?

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Can the absolute refractive index of a medium be less than one?

Can the value of the absolute refractive index be lesser than 1?

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Solution

No, the absolute refractive index of a medium cannot be less than one because the speed of light in any medium is always less than that in a vacuum.

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Chapter 2: Light - Frequently Asked Questions in Board Examination [Page 154]

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Frank Physics Part 2 [English] Class 10 ICSE
Chapter 2 Light
Frequently Asked Questions in Board Examination | Q 29. (c) (i) | Page 154

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