1. Quantum Physics Particle Nature of EM Radiation Photoelectric Effect Electronvolt Wave Nature of Particles De Broglie Equation

2. Review: Cathode Ray Electric Force is equal to magnetic Force Electric Force is equal to magnetic Force e/m value was determined e/m value was determined

3. Review: Millikan Oil-Drop Experiment Electric Force is equal to Gravitational Force Electric Force is equal to Gravitational Force e value was determined e value was determined Hence, m of electron was also determined Hence, m of electron was also determined

4. Macroscopic Models A model is a way of explaining something difficult in terms of something more familiar. A model is a way of explaining something difficult in terms of something more familiar. Example: Example: –How a brain works  Telephone exchange, computer or library –Electricity  Water in a pipe  Electrons, electric field –See p. 133 of book Table 16.1 for other models

5. Particles versus Waves

6. Electrons as Particles

7. Electrons as Waves

8. Electron Diffraction

9. If electrons can behave as waves, can light behave as particles?

10. Light as Particles

11. Photons Photons are particles that make up light Photons are particles that make up light Photoelectric effect is stream of particles of light Photoelectric effect is stream of particles of light Energy of a photon Energy of a photon E = hf  Where h= 6.63 x 10(-34) Js  Planck’s constant Einstein’s relation Einstein’s relation

12. The Photoelectric Effect Threshold Frequency Threshold Frequency Maximum Kinetic Energy Maximum Kinetic Energy

13. The success of the photon model in explaining the photoelectric effect

14. Waves, Particle and People Wave-Particle Duality Wave-Particle Duality Rules for Light Rules for Light –Particle when it interacts with matter –Wave when its wavelength is similar to the dimensions of any object with which it interacts Rules for Matter Rules for Matter –de Broglie Equation –Human waves

15. Atomic Spectra

16. Emission Spectra Emission Spectra –Light emitted by hot gases Absorption Spectra Absorption Spectra –When white light is passed through a cool gas Explanation Explanation –Two points to remember –Quantization of energy –Energy ladders