World 1 · Reflection & Refraction · 9 minSnell's Law
The exact refraction equation
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At a boundary between two media, light refracts — it changes direction. The angles obey Snell’s law:
n₁ · sin θ₁ = n₂ · sin θ₂
where θ is measured from the normal in each medium.
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Light passes from air into water (n = 1.33), meeting the surface 45° from the normal. The refracted ray is about…
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