1. Refraction Chapter 15

2. Refraction Refraction: The bending of light as it travels from one medium to another Refraction occurs when light’s velocity changes The speed of light varies with the medium

3. Refraction Θ r = Angle of Refraction Θ i = Angle of Incidence

4. Index of Refraction Index of Refraction = speed of light in vacuum speed of light in medium

5. *Only valid for light with wavelength of 589 nm in a vacuum (p. 564)

6. Snell’s Law Snell’s Law determines the angle of refraction n i sin(θ i ) = n r sin(θ r ) n i = Index of refraction of first medium n r = Index of refraction of second medium θ i = Angle of Incidence θ r = Angle of Refraction

7. Bending relative to the normal When light passes from a medium with a low index of refraction to a medium with a high index of refraction, the ray bends toward the normal When light passes from a medium with a high index of refraction to a medium with a low index of refraction, the ray bends away from the normal

8. CATBEAR trying to catch a fish!!!

9. Sample Problem (p.567 #4) Sunlight passes into a raindrop at an angle of 22.5° from the normal at one point on the droplet. What is the angle of refraction?

10. Sunlight into a raindrop Will the ray bend away from the normal or towards the normal? –Low n to high n, the ray will bend toward the normal θiθi θrθr

11. Use Snell’s Law