fénytörési

Fénytörési, also known as refraction, is the bending of light as it passes from one medium to another. This phenomenon occurs because the speed of light changes when it enters a different medium. For example, light travels faster in air than in water. When light enters water from air at an angle, the part of the light wave that enters the water first slows down, causing the wavefront to pivot and the light ray to bend. The amount of bending depends on the refractive index of the two media. The refractive index is a measure of how much light is slowed down by a material. A higher refractive index means light travels slower in that medium.

The law of refraction, also known as Snell's Law, describes the relationship between the angles of incidence and refraction and the refractive indices of the two media. It states that the sine of the angle of incidence multiplied by the refractive index of the first medium is equal to the sine of the angle of refraction multiplied by the refractive index of the second medium. Fénytörési is responsible for many everyday optical phenomena. For instance, it explains why a straw in a glass of water appears to be bent, why lenses can focus light, and how rainbows are formed. The dispersion of light, where white light is split into its constituent colors, is also a consequence of refraction, as different wavelengths of light have slightly different refractive indices and therefore bend at slightly different angles.