๐ Snellโs Law (Refraction) Calculator
Enter the incident angle and the refractive indices of two media (n1, n2) to calculate the refraction angle using Snellโs law (n1รsinฮธ1=n2รsinฮธ2). If total internal reflection occurs, this is indicated along with the critical angle.
How to use
- Enter the refractive index of the incident medium (n1), e.g. air = 1.0.
- Enter the incident angle (degrees).
- Enter the refractive index of the second medium (n2), e.g. water = 1.33, glass = 1.5.
- The refraction angle is shown, or if total internal reflection occurs, that fact and the critical angle are shown instead.
FAQ
What is total internal reflection?
When light travels from a denser medium (higher refractive index) into a less dense one, and the incident angle exceeds the critical angle, all the light is reflected instead of refracting. This is the principle behind optical fibers.
How is the critical angle calculated?
Itโs calculated as sin(critical angle) = n2/n1, and only exists when n1 is greater than n2 (going from denser to less dense).
What values should I use for refractive index?
Vacuum and air are approximately 1.0, water is approximately 1.33, common glass is approximately 1.5, and diamond is approximately 2.42 โ use the value for your medium.