How it works
n₁sin θ₁ = n₂sin θ₂. Angles are measured from the surface normal. Detect total internal reflection.
Input definitions
- Incident medium refractive index
- Enter the value in the labeled unit.
- Transmitted medium refractive index
- Enter the value in the labeled unit.
- Incident angle from the normal (degrees)
- Enter the value in the labeled unit.
A worked example
- Incident medium refractive index
- 1
- Transmitted medium refractive index
- 1.5
- Incident angle from the normal (degrees)
- 30
Assumptions & limits
Ideal educational model in the stated SI units. Real equipment, structural design and safety decisions need appropriate professional analysis; losses are excluded unless entered.
Sources & review
Maintained by AnsRio. Methods and examples use automated checks; this does not imply independent professional certification.
Method updated 2026-10-18. Content checked against the stated method and examples. Our verification approach.
Common questions
When does total internal reflection occur?
When light travels from higher to lower refractive index above the critical incident angle. No real transmitted ray angle then exists.
How does Snell’s law refraction angle work?
n₁sin θ₁ = n₂sin θ₂. Angles are measured from the surface normal. Detect total internal reflection.
What should I check before using Snell’s law refraction angle?
Ideal educational model in the stated SI units. Real equipment, structural design and safety decisions need appropriate professional analysis; losses are excluded unless entered.