# Index of refraction and wavelength

## Homework Statement:

The dependence of the index of refraction of a material on wavelength is...

## Relevant Equations:

None
The problem is multiple choice.
A) refraction b) diffraction c) reflection d) dispersion

An explanation would also be greatly appreciated!

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Homework Helper
Gold Member
As a homework helper, I'm really not supposed to give the answer, but on this one, I will bend the rules a little, because any explanation of this leads you immediately to the answer. ## \\ ## With a prism, basically light bends as it enters the prism, and that is called refraction. The emerging angle depends on Snell's law, which contains the index of refraction ## n ## in the formula. Because the index ## n ## of refraction can be wavelength dependent, and it is for the kind of glass that is used in a prism, the different wavelengths, basically the colors of the rainbow, are bent different amounts, and the light is separated into the different colors. Alternatively, the speed of light ##v=\frac{c}{n} ##,(## c ## is the speed of light in the vacuum), is different for the different wavelengths inside a material, (since index ## n ## changes slightly with wavelength), and both the separating of the colors, and the speed of light being different for different wavelengths are known as "dispersion".

kuruman
Homework Helper
Gold Member
This reminds me of a similar question I once asked on a test. Instead of multiple choice, students had to put the name of the process in the appropriate blank. One student hedged his bets and put down reflaction ...