1. Refraction and Polarization of Light 3/10/04 Thursday: group project and in-class exercises Friday: Waves & Particles Coming up on Friday March 26 – Saturday March 27 – Physics Conference – Nobel Laureate Leon Lederman (Fri. 8 pm) – Student Poster Presentations

2. Law of Reflection n1n1 n2n2 i rfl rfr  rfl ii  rfr “angle of incidence = angle of reflection” Law of Refraction “Snell’s Law”

3. Related Questions: Where does the “Law of Reflection” come from? Why does light change speed in different media? Why does the frequency of light remain constant in different media? Has to do with the electromagnetic nature of light and the interaction of electromagnetic radiation with matter  the electric field interaction with the electrons

4. Electromagnetic Radiation Review Changing E  Changing B  Changing E  Changing B, … http://webphysics.davidson.edu/Applets/ Retard/Retard_FEL.html How to get these kinds of changing fields?  Accelerated charges Polarized vs. Unpolarized

5. Re-Radiation + Interference/Diffraction  Reflection  Changing speeds  Polarization Polarization  Absorption  Reflection (video demo)  Scattering (video demo)

6. Not all wavelengths are equal… Consider single slit diffraction: a 

7. Different wavelengths interfere diffract refract scatter Differently  “dispersion”  rainbows! Scattering: longer wavelengths diffract more…  bend around corners  get around obstacles more than shorter wavelengths (video demo)