University Physics Volume 3 - 1.3 Refraction - EXAMPLE 1.2

EXAMPLE 1.2
Determining the Index of Refraction

Find the index of refraction for medium 2 in Figure (a), assuming medium 1 is air
and given that the incident angle is
°
and the angle of refraction is
°.

You can change angles and the result will be calculated for your angles.

Strategy
The index of refraction for air is taken to be 1 in most cases (and up to four significant figures, it is 1.000). Thus, n₁ = 1.00 here. From the given information, θ₁ = 30.0° and θ₂ = 22.0°.
With this information, the only unknown in Snell’s law is n₂, so we can use Snell’s law to find it.

Solution
From Snell’s law, we have
n₁ sin θ₁ = n₂ sin θ₂

n₂ = n₁ sinθ₁ / sinθ₂.
Entering known values,
n₂ = 1.00 sin 30.0° / sin 22.0° = 0.500 / 0.375 = 1.33