given is a graph of n(lambda) vs lambda where n is the index of refraction(adsbygoogle = window.adsbygoogle || []).push({});

N(1000) =1.45

Estimate Vphase and group velocity using the above info.

i know that [tex] n = \frac{c}{v_{\phi}} = \frac{ck}{\omega} [/tex]

i cant simply susbtitute into that above relation because the lambda given is that lambda in the vacuum and thus the lambda would be different in the medium. Also oncei found v phase how would i go about finding group velcoity, since group velocity is a derivative, do i simply pick off two points on the graph and find the slope?

But first i need to figure out phase velocity which i cant get and i dont know if its right

Please help!

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# Homework Help: Index of refraction Vphase

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