Total external reflection
= Total external reflection
{wiki=Total_external_reflection}
Total external reflection is a phenomenon that occurs when a wave, such as light, travels from a medium with a higher refractive index to a medium with a lower refractive index and strikes the boundary at an angle greater than a certain critical angle. This angle is specific to the materials involved and can be calculated using Snell's law, which relates the angles and indices of refraction of the two media.