Physics 2102 Jonathan Dowling QuickTime and a decompressor are needed to see this picture Lecture 35 WED 15 APR Ch 33 8 10 QuickTime and a decompressor are needed to see this picture QuickTime and a decompressor are needed to see this picture Reflection and Refraction light finds a surface separating When two media air and water for example a beam gets reflected bounces and another gets refracted bends Law of reflection Light Bounces the angle of incidence 1 equals the angle of reflection 1 1 1 of Refraction Light Bends Law n2 sin 2 n1 sin 1 Snell s Law he index of refraction of the medium uum n 1 In air n 1 In all other media n Plastic Speed of Light is Slowed n Glass n 1 n 1 QuickTime and a decompressor are needed to see this picture Hits Sand Turns Left Road v c n n 1 v c vL v Example er has n 1 33 How much does a beam incident at 45 o refracts n2 sin 2 n1 sin 1 sin 2 n1 n2 sin 1 1 1 33 sin 45o 0 0098 2 32o QuickTime and a decompressor are needed to see this picture QuickTime and a decompressor are needed to see this picture Water on Desert Road Illusion The index of refraction decreases with temperature the light gets refracted and ends up bending upwards We seem to see water on the road but in fact Water on the Desert Road Mirage QuickTime and a decompressor are needed to see this picture Chromatic Dispersion dex of refraction depends on the wavelength color of the l QuickTime and a decompressor are needed to see this picture The Single Rainbow QuickTime and a decompressor are needed to see this picture The Double Rainbow Total Internal Reflection QuickTime and a decompressor are needed to see this picture Total Internal Reflection to air the law of refraction uses From glass n 2 n1 so 2 1 it may reach 90o or more the ray is reflected instead of refracted 2 n2 1 ondition for TIR 2 sin 2 n1 sin 1 2 1 n1 1 For glass fused quartz n 1 46 and the critical angle is 43o optical fibers QuickTime and a decompressor are needed to see this picture The cut of the diamond favors total internal reflection Most rays entering the top of the diamond will internally reflect until they reach the top face of the diamond where they exit This gives diamonds their A bright fiber optic is a glass hair sparkle which is so thin that once light enters one end it can never strike the inside walls at less than the critical angle The light undergoes total internal reflection each time it strikes the wall Fiber optic cables are used to Fiber Optic Cables QuickTime and a decompressor are needed to see this picture QuickTime and a decompressor are needed to see this picture FIBER OPTIC GUIDED MISSILE QuickTime and a decompressor are needed to see this picture QuickTime and a decompressor are needed to see this picture Polarization By Reflection polarization of Different light get reflected and refracted with different amplitudes birefringence At one particular angle the parallel polarization is NOT reflected at all This is the Brewster angle B and o B r 90o Polarizing Sunglasses n1 sin n2 sin 90 n2 cos n2 tan n1 Polarized Sunglasses QuickTime and a decompressor are needed to see this picture QuickTime and a decompressor are needed to see this picture
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