Physics 212 and 222 Refraction and Lenses TOC

Physics 212 and 222 Refraction and Lenses TOC Refractive Index Snell’s Law Dispersion Rainbows Total Internal Reflection Apparent Depth 1

Physics 212 and 222 Refraction and Lenses TOC Refractive Index The speed of light in a vacuum is The speed of light in other materials (media) is always slower. The index of refraction (refractive index) is the ratio of the speed of light in vacuum over the speed of light in the material. Refractive index is a property of the material. 2

Physics 212 and 222 Refraction and Lenses How does refractive index change the light? TOC θ 1 θ 2 3

Physics 212 and 222 Refraction and Lenses n 1 Snell’s Law n 2 TOC θ 1 ’ θ 1 4 θ 2

Physics 212 and 222 Refraction and Lenses TOC Dispersion Index of refraction is a function of wavelength. Longer wavelengths usually move faster in a medium. 5

Physics 212 and 222 Refraction and Lenses Rainbows TOC Primary rainbows come from one reflection. Secondary rainbows come from two reflections 6 © 1999 – 2002, HMI, Arbeitsgruppe Nukleare Messtechnik, Prof. W. von Oertzen

Physics 212 and 222 Refraction and Lenses The critical angle for total internal reflection is θ 1 = θc when θ 2 = 90 o. TOC θ 2 n 2 θc θ 1 7 n 1 90 o

Physics 212 and 222 Refraction and Lenses The apparent depth of the shark is given by equation TOC n 2 d’ d 8 n 1 as calculated by the

Physics 212 and 222 Refraction and Lenses TOC Refractive Index Snell’s Law Dispersion Rainbows Total Internal Reflection Apparent Depth 9