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Chapter -10, Wave, Optics, Huygens Principle:, * Each Pont on a wavefront is a Source of, Secondery disturbance and the Secondary, wavelets oniginating from these Points, Spread out, Speed of the wave., in all, directions with the, 米, The new wavefront at, ary, later, obtained by taking the tangential Surface, in tue, of Secondary wavelets, forward, direction to all the Spherer, Reflection of Plane, Principle:, waves using Huygen's, Sulahhii

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This represents the Second low of, law of reraction,, light travels from rarer, Jenser medium, it bends towards, Shorter thao, refraction, or, Snell's, when', medium to, normal, This means, AD, is, less than Vi. Hence, light, medium, BC, has higher velocity in, 8 Smaller velocity in, OY, Vq is, raver, Jenser medirem, Interfenence of light':, The modification in the distribution of, light energy due to SuferPosition, of two or, Called, interference, & derk, more, waves of, light, is, of light. Jhe, regions, bands, alternate bright, observed and are Called interferance, froinges,, interference, Or, Coherent Sources:-, f light Continuously, woves havng, 2ifference., Any two Sourcer, emitting, light, Constant Phase, Called Coherent Sourees, zero, or, Ore, Constructive and destructive interference, of the, ima medlum, Let a, Consider two light waves, Same frequemiy travelling, in the Same' digechion., a2, be the amplitudes of the two, displacement, of any fwo, farticle in the miediums due to these, instant, waves, the, woves, at, Ony, of tme t are, 1= a, Sin wt