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Published byAsher Robertson Modified over 9 years ago
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Reflection and Refraction
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Reflection Two laws of reflection Angle of incidence = angle of reflection The angle of incidence, angle of reflection and normal all lie in the same plane
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Refraction Light travels more slowly in glass, perspex etc than in air or in a vacuum If light meets a block of glass etc head on it goes straight through If light meets a block of glass etc at an angle it bends
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Refractive Index Light travels fastest through a vacuum Light travels more slowly through other materials like glass, water or perspex The Refractive Index links the speed of light in a vacuum to the speed of light in a medium Refractive index n = speed of light in a vacuum speed of light in the medium n = 1.33 for water n = 1.5 for glass (approx – depends on the glass)
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Laws of Refraction Law 1 Snell’s Law Law 2 The incident ray, refracted ray and normal all lie on the same plane n = sin i sin r
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Relative Refractive Index When a ray travels from one medium to another, the relative refractive index is n(first medium) n(second medium) and you use this relative n in Snell’s Law
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Calculations using the laws of refraction 1. Calculate the relative refractive index 2. Relative n = n (for first medium) n (for second medium) 3. Use the relative n in Snell’s Law to solve the problem
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