Snell's Law (1 Viewer)

[khorne]

I am just finalising my physics summaries, and am slightly confused about this.

I know Snell's law states that v(1)/v(2) = sin 1/sin r = n(2)/n(1) = constant (index of refraction). But since we can use the indexes of refraction in Snell's law, am I to assume that those indexes are absolute ones (i.e relative to a vacuum) and that the constant, or index of refraction is infact the relative index of refraction, i.e between the two mediums?

 

[darkchild69]

I am just finalising my physics summaries, and am slightly confused about this.

I know Snell's law states that v(1)/v(2) = sin 1/sin r = n(2)/n(1) = constant (index of refraction). But since we can use the indexes of refraction in Snell's law, am I to assume that those indexes are absolute ones (i.e relative to a vacuum) and that the constant, or index of refraction is infact the relative index of refraction, i.e between the two mediums?

Yes, the constant is a relative index of refraction. This tells you how many times more (or less) optically dense medium 2 is compared to medium 1.

Example water --> glass would equal 1.5/1.33 which is somewhere around 1.12

The constant is only ever the absolute index of refraction of medium 2 when medium 1 = vacuum (hence n1 = 1, so n2/n1 = n2/1 = n2)

 

[khorne]

Thanks for that.
+rep