AbraCalc

Snell's Law: Air to Glass at 60°

Light entering glass (n = 1.5) from air at 60° refracts to approximately 35.26°.

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How to use this tool

  1. Enter refractive index n₁, angle of incidence θ₁ and refractive index n₂ in the fields above.
  2. Results update instantly as you type — or click Calculate.
  3. Read your angle of refraction θ₂ and the full breakdown beneath it.

At steeper angles of incidence, refraction is more dramatic — here a 60° ray bends to just over 35° inside the glass.

Frequently asked questions

What is total internal reflection?
When light in a denser medium (e.g. glass) hits the boundary at an angle greater than the critical angle, all light is reflected back. This is the principle behind fibre-optic cables.
What are common refractive indices?
Vacuum/air: 1.0, water: 1.33, crown glass: 1.52, diamond: 2.42.