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Chapter 33-7 Polarization. The Beginning of Optical Physics (Light and Optics). Transverse Wave Property (Electric Field Considered). Historical attempts to characterize light. Ancient idea light emanates from eye to illuminate object Newton (18 th century)
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Chapter 33-7 Polarization The Beginning of Optical Physics (Light and Optics) Transverse Wave Property (Electric Field Considered)
Historical attempts to characterize light • Ancient idea • light emanates from eye to illuminate object • Newton (18th century) • light is particulate and moves faster in transparent materials • Young (1801) • interference experiments demonstrates wave nature of light • Einstein (early 20th century) • explains photoelectric effect by assuming a particulate nature of light (lumps of waves with E = hf)
Known Properties of Light • Explained classically by Maxwell’s Equations (in 1860) • Transverse Wave • polarization • Wave speed • speed of light in a vacuum • 3.00 ´ 108 m/s • speed of light slower in media • Particle (?) • the photon (E = hf) • dual nature of light
Polarization (Source of light is excited atoms) Plane polarized Unpolarized
Methods of chararacterizing the light wave • Wavefronts (3D surface of constant phase) • Huygen’s Principle • ray construction • lines perpendicular to wavefronts showing direction of motion of wave • the plane wave
Polarizer-Analyzer Malus’sLaw
Reflection • specular reflection (a) • diffuse reflection (b) • Law of Reflection q1 = q1’
Refraction • Character of the wave in different (transparent) media • wave travels slower • Index of refraction n = c/v • Law of Refraction (Snell’s Law)n1 sin q1 = n2 sin q2will derive in ch 35
Total Internal Reflection Ex 33-4 pg. 909
Combined Reflection and Refraction • Dependence on angle • Total Internal Reflection (ray 4 is critical ray)
Polarization by Reflection Brewster’s Law
Chromic Dispersion • The Prism