1. Reflection & Refraction Of light By: Ahmed

2. Definitions Luminous objects – generate their own light (the sun) Illuminated objects – reflect light (the moon)

3. Definitions Line of Sight – a line from an object or image to your eyes (light from the object travels along this line to your eyes)

4. Rays of Light Incident Ray – leaves the object and strikes the mirror Reflected Ray – leaves mirror and strikes your eye The reflected ray is on the line of sight from the image to your eye.

5. Law of Reflection Angle of incidence equals angle of reflection.

6. Law of Reflection Normal – line perpendicular to the mirror surface Angle of incidence – angle between incident ray and normal Angle of reflection – angle between reflected ray and normal

7. Diffuse Reflection

9. Refraction The change in direction of a wave as is crosses the boundary between two media in which the wave travels at different speeds.

10. Snell’s Law

11. Problem 1 SubstanceIndex of Refraction Air (vacuum)1.00 Water1.33 Alcohol1.36 Quartz1.46 Lucite1.50 Benzene1.50 Glass – Crown1.52 Plexiglas1.55 Glass – Flint1.61 Diamond2.42 A ray of light in air is approaching the boundary with water at an angle of 52 degrees. Determine the angle of refraction of the light ray. Refer to the table of indices of refraction if necessary.table of indices of refraction

12. Answer 1 Given: n i = 1.00 (from table)n r = 1.333 (from table)from table Θi = 52 degrees Find: Θ r =??

13. Problem 2 A ray of light in air is approaching the boundary with a layer of crown glass at an angle of 42.0 degrees. Determine the angle of refraction of the light ray upon entering the crown glass and upon leaving the crown glass.

14. Answer 2 Given : Boundary #1 ni = 1.00 (from table) nr = 1.52 (from table) Θi = 42.0 degrees Boundary #2 ni = 1.52 (from table) nr = 1.00 (from table) Find: Θr at boundary #1 and Θr at boundary #2

15. Worksheet