Class

1

• Class 21 Feb. 19
• Light as a Wave and a Particle
• Pick up Updated Unit II Course Calendar
• Pick up Lecture 21 handout
• Pick up Feynman Chapter 37
• Homework 6 Due FRIDAY 2PM

2
X-Ray Diffraction Crystal Structure
3
X-Ray Diffraction Bragg Condition
4
Scattering of Light l vs. d
5
Three Great Mysteries at the Turn of the 20th
Century Involving Light
6
Experimental BlackBody Curve
7
Rayleigh-Jeans Formula A Classical Approach to
the BlackBody Problem
8
Calculating the average energy per standing wave,
, via classical thermodynamics
9
Rayleigh-Jeans Formula
Plancks Formula
10
Photoelectric Effect Experimental Schematic
V
d
11
Photoelectric Effect Classical Mysteries
12
Photoelectric Effect Resolved
Einsteins Photon Hypothesis
KEmax (J or eV)
frequency (Hz)
13
Classical (Elastic) Collisions
Conservation of (Kinetic) Energy and Momentum
14
Classical (Elastic) Collisions (continued)
Conservation of (Kinetic) Energy and
Momentum
15
Relativistic (Elastic) Collisions
Conservation of Energy and Momentum
16
Relativistic (Elastic) Collisions (continued)
Compton Effect