How light behaves at a boundary By Victoria Skinner 17.1 How Light law of reflection *If 2 parallel beams strike a mirror 2 reflected beams are also parallel *If a line is perpendicular to a mirror it is the normal because it is normal to the surface. reflections *regular reflection- happens when light is reflected back to the observer in parallel beams *Diffuse reflection- the scattered, fuzzy reflection from a rough surface where light is reflected Refraction of light Angle of refraction Angle of refraction- the angle the refracted ray makes with the normal to the surface Optically dense Optically dense- materials with larger indices of refraction with respect to other materials Snell’s law • *Snell's law- states that the ratio of sine of the angle of refraction is a constant Incident Ray traveling in a less dense medium index of refraction • *index of refraction- the ratio of the speed of light in a vacuum to its speed in a material * *The index of refraction often can be measured by directing a ray of light onto the substance's surface, measuring the angle of incidents and angle of refraction,then using Snell’s law . . problem solving strategies• • • • • 1.draw a diagram showing 2 media and label 2. Draw the incident ray 3.use protractor 4.use Snell’s law 5.use protractor • 6.evaluate. *when solving problems involving refractions and reflections of light a one will use a ray diagram . * when setting up a Snell's law problem assign symbols for the various quantities, and check your results. WORKS CITED Displacement Sensor Topic: Principle of Regular Reflection Measurement. OMRON Corporation , 2011. Web. 28 Feb. 2011. <http://www.omronap.co.th/FAQ/ FAQ01367/index.asp>. Dizzo95. "light refraction." 12 Nov. 2009. youtube. Web. 28 Feb. 2011. YouTube<http://www.youtube.com/watch?v=OdcHCRF00jM&NR=1>. "Light and Geometric Optics." OoCities.org. , Oct. 2009. Web. 28 Feb.2011.<http://www.oocities.org/rjwarren_stm/Physics_Notes/ Unit1_Light.html>. "Refractometers." Lab Safety Supplies. GHC Specialty Brands,, 2011. Web. 28 Feb. 2011. <http://www.labsafety.com/refinfo/ezfacts/ezf118.htm>. "Unit 2 Refraction of Light." Creative Commons Attribution Share-Alike 3.0 License. chemicalparadigms, 2011. Web. 28 Feb. 2011. ht <http://https://chemicalparadigms.wikispaces.com/ Unit+2+Refraction+of+light>. Weblog post. Analysing Refraction of Waves. Nuffnang Web. 28 Feb.2011. <http://fiziknota.blogspot.com/2008/03/ analysing-refraction-of-waves.html>. Zitzewitz, Paul W, comp. Physics Principles and Problems. 2002 ed. New York: Glencoe, 2002. Print.