Vocabulary

refraction

optical density

principle of reversibility

index of refraction

angle of refraction

dispersion

angle of deviation

critical angle

total internal reflection

fibre optics

MAIN IDEA: Snell's law describes the relationship between the incident and refracted angles of a light ray and the indices of refraction of two media: $n_{1}sin{}_1=n_{2}sin{}_2.$ The index of refraction, $n,$ of a medium is the ratio of the speed of light in a vacuum, $c,$ to the speed of light in the medium, $v$:$n=\frac{c}{v}.$

Figure $1$ shows a ray of light crossing the boundary between two media, $1$ and $2.$ Which medium has the higher index of refraction? Explain your answer.

$.100$

STUDY TIP

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Figure $1$