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CBSE Class 9 Answered

what is refractive index?why is it inversely proportional to speed of light in a particular medium?
Asked by ashwati | 22 Dec, 2008, 10:24: PM
answered-by-expert Expert Answer

Refractive index of 2nd medium w.r.t. 1st medium  = sin i/ sin r ; where 'i' is the angle of incidence and 'r' is the angle of refraction.

Also,

refractive index  = speed of light in vacuum / speed of light in the given medium.

 The speed of light in vacuum has a fixed value, so

 r.i. of a substance is inversely proportional to its speed in that medium.

Answered by | 23 Dec, 2008, 11:09: PM

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CBSE 9 - Physics
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