Light Refraction Diagram
n1 * sin(theta1) = n2 * sin(theta2)
Snell's Law - The fundamental equation of light refraction
Find Unknown Refractive Index
Determine the refractive index of an unknown material using measured angles and a known medium.
Common Refractive Indices
| Material | Refractive Index (n) | Critical Angle (to air) |
|---|---|---|
| Vacuum | 1 | N/A |
| Air | 1.0003 | N/A |
| Water | 1.333 | 48.6 deg |
| Glass | 1.52 | 41.2 deg |
| Diamond | 2.417 | 24.4 deg |
| Ice | 1.31 | 49.8 deg |
| Olive oil | 1.47 | 42.9 deg |
| Acrylic | 1.49 | 42.2 deg |
| Amber | 1.55 | 40.2 deg |
| Sapphire | 1.77 | 34.4 deg |
Understanding Snell's Law and Light Refraction
This Snell's law calculator helps you understand how light behaves when passing between different transparent materials. Whether you are studying optics, designing optical instruments, or solving physics problems, this tool provides accurate calculations with detailed explanations.
What is Snell's Law?
Snell's Law (also called the law of refraction) describes how light bends when it passes from one transparent medium to another. The mathematical relationship is:
n1 * sin(theta1) = n2 * sin(theta2)
Where n1 and n2 are the refractive indices of the two media, and theta1 and theta2 are the angles from the normal.
What is Total Internal Reflection?
Total internal reflection (TIR) occurs when light traveling in a denser medium hits the boundary with a less dense medium at an angle greater than the critical angle. Instead of refracting, all the light is reflected back.
Applications:
- Fiber optic cables for internet and communications
- Prisms in binoculars and periscopes
- Diamond brilliance and sparkle
- Endoscopes for medical imaging
What is the Critical Angle?
The critical angle is the minimum angle of incidence at which total internal reflection occurs. It only exists when light travels from a denser medium to a less dense medium.
theta_c = arcsin(n2 / n1)
For example, the critical angle for glass-to-air is about 41.8 degrees, and for water-to-air is about 48.6 degrees.
Real-World Applications
- Eyeglasses and Contact Lenses: Correcting vision using refraction
- Camera Lenses: Focusing light onto sensors
- Fiber Optics: High-speed data transmission
- Gemology: Identifying gemstones by refractive index
- Underwater Photography: Compensating for water refraction
- Atmospheric Optics: Understanding rainbows and mirages