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Class 10 Physics (India)

Course: Class 10 Physics (India)>Unit 1

Lesson 9: Absolute & relative refractive index

Absolute & relative refractive index

Let's explore the refractive index in detail. We will see the difference between absolute and relative refractive index. Created by Mahesh Shenoy.

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• Why can’t we mention the refractive index with respect to air and call it “relative index” (with respect to air / vaccum ) ?
• Because defining refractive index with respect to air/vacuum is so useful that it got its own term.
• We write refractive index as “mew” ( the Greek alphabet) and not “n” ?
• Either one can be used. In most textbooks that I found, "n" was used, but "mu" was also used in some textbooks. I would advise you to go ahead with what is given in your textbook.
Happy if I was able to help. :)
• Isn’t speed of light in water more than the speed of light in oil? In the video, he says the opposite..
• he does! maybe it was purely as an example.
• Can our first medium be vacuum? I mean, can we say light travelling from vacuum to any another medium ? And will it be called as absolute refractive index ?
• yes and generally in most cases, we get our first medium as vacuum or air. And yes when we choose vacuum or air as a reference medium we call it Absolute Refractive Index.
(1 vote)
• Which one is correct?
n12 = 1/2 or n12 = 2/1?