3. Reflection & Refraction of Light Reflection: specular (mirror) vs diffuse angle of incidence = angle of reflection Refraction: Snell’s Law n 1 sin  1 = n 2 sin  2

4. Total Internal Reflection Snell’s Law from glass to air: n 1 sin  1 = n 2 sin  2 n g sin  critical = n air sin  n air

7. Group Problem If a beam of light takes 0.106 nanoseconds to travel the distance L = 2.22 cm as shown below, what is the angle of incidence that the beam makes with the surface?2 cmL=2.22 cmθin2=1.5n1=1.0