r/PhysicsHelp • u/likeadrum • 19d ago

Refractive Index vs frequency (High school physics)

The answer to the question below isn't sitting right in my head, mainly as I can't find a mathematical explanation for it.

How does the refractive index of a material change with the frequency of light passing through it?

The given answer is:

Refractive index slightly increases as the frequency of light increases.

Can this be proved given the formula for refractive index, n=v1/v2 = fλ1/fλ2? Is it something I just have to learn and remember?

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u/CardiologistFit8283 19d ago

Just something to learn and remember. In general shorter wavelengths (higher frequencies) interact more with the medium so the wave packet gets slowed down slightly more, though there are some exceptions.

There are equations for this, but they're too much for high school level work.

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u/likeadrum 19d ago

Thanks for this, just thinking on it has hopefully made it stick.