# Which symbol is more relevant for refractive index: μ or n?

• anyonebutangel
In summary, "mew" (μ) and "n" are both used for depicting refractive index, but "mew" does not typically represent refractive index. It is an old-fashioned symbol dating back to 1815 and is still used in some outdated textbooks. The accepted modern symbol for refractive index is "n".
anyonebutangel
Homework Statement
when should we use the symbol "mew" for refractive index and when should the alphabet n be used?
Relevant Equations
no equations
both "mew"(sorry i couldn't get the symbol on on my keyboard so I'm writing it) and n are used for depicting refractive index i want to know which is more relevant and is there any reason for it or which symbol should be used in what cases.

"Mew" (##\mu##) is does not typically represent either the index of refraction, which is almst always shown as "n", or permittivity, which is sually shown as "##\epsilon##".

##\mu## represents permeability, a magnetic quantity.
The quantity ##1/\sqrt {\mu\epsilon}## is the speed of light in a medium of permittivity ##\epsilon## and permeability ##\mu##.

The above is for SI aka mks.

anyonebutangel and berkeman
anyonebutangel said:
Homework Statement:: when should we use the symbol "mew" for refractive index and when should the alphabet n be used?

"mew"(sorry i couldn't get the symbol on on my keyboard so I'm writing it)
If you click "Reply" below the post by @rude man you will see how he used the double-# notation to generate the inline LaTeX version of that greek character. Also, if you click on the squareroot symbol in the upper right of the Edit window, you will get a number of greek characters that you click on, including μ

anyonebutangel
berkeman said:
If you click "Reply" below the post by @rude man you will see how he used the double-# notation to generate the inline LaTeX version of that greek character. Also, if you click on the squareroot symbol in the upper right of the Edit window, you will get a number of greek characters that you click on, including μ

View attachment 269022
sorry about all the edits. Sould have looked before leaping.

berkeman
anyonebutangel said:
when should we use the symbol "mew" for refractive index and when should the alphabet n be used?

μ should not be used for refractive index. It is a very old-fashioned symbol for refractive index dating back to 1815-ish (https://en.wikipedia.org/wiki/Refractive_index).

It was still in use in the 1960s (when I studied physics) and I guess it may still be used in very some out-of-date textbooks.

The accepted moden symbol 'n' should always be used.

etotheipi
berkeman said:
If you click "Reply" below the post by @rude man you will see how he used the double-# notation to generate the inline LaTeX version of that greek character. Also, if you click on the squareroot symbol in the upper right of the Edit window, you will get a number of greek characters that you click on, including μ

View attachment 269022

berkeman
Steve4Physics said:
μ should not be used for refractive index. It is a very old-fashioned symbol for refractive index dating back to 1815-ish (https://en.wikipedia.org/wiki/Refractive_index).

It was still in use in the 1960s (when I studied physics) and I guess it may still be used in very some out-of-date textbooks.

The accepted moden symbol 'n' should always be used.
O.K thank you.

## 1. What is the symbol for refractive index?

The symbol for refractive index is n.

## 2. How is refractive index measured?

Refractive index is measured by determining the ratio of the speed of light in a vacuum to the speed of light in a given medium.

## 3. What does a high refractive index indicate?

A high refractive index indicates that light travels slower in the medium, meaning that the medium is more optically dense.

## 4. How does refractive index affect the bending of light?

The higher the refractive index of a medium, the more the light will bend when passing through it.

## 5. Can refractive index be negative?

Yes, refractive index can be negative in certain materials, such as metamaterials, where the phase velocity of light is faster than the speed of light in a vacuum.

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