Refraction & Snell's Law
Quantify optical ray deflection across dielectric interfaces and determine critical angles for total internal reflection.
Snell's Law & Total Internal Reflection
When light crosses a boundary between two transparent media with differing refractive indices, its velocity changes, causing the ray trajectory to bend. Snell's law quantifies this relationship:
If light travels from a denser medium (higher n₁) toward a rarer medium (lower n₂), there exists a critical angle θ_c at which the refracted ray grazes the interface at 90°. Exceeding this angle causes 100% of incident radiant power to reflect back into the first medium—a phenomenon termed Total Internal Reflection (TIR), which forms the physical basis for fiber-optic telecommunications.
Model Assumptions & Optical Parameters
- Monochromatic plane wave optical ray incident upon an optically flat, non-absorbing interface.
- Isotropic media with uniform refractive indices.
Frequently Asked Questions
What causes light to refract?
Refraction occurs because light travels at different phase velocities in media of different optical densities (v = c / n).
What is total internal reflection?
When light travels from an optically denser medium to a rarer medium at an angle exceeding the critical angle, 100% of the light reflects back with zero transmission.
More from Alok Das
These interactive tools are personal side-projects built for exploration and utility. My primary professional commitment is in M.Sc. Chemistry, analytical research, and laboratory methodology.