2. Modern Physics Review Get a board, marker, partner, and wipey thing

3. Which phenomenon can be explained by both the particle model and wave model? 1. Polarization 2. Reflection 3. Interference 4. diffraction

4. A sound wave cannot be... 1. Reflected 2. Refracted 3. Diffracted 4. polarized

5. Describe the photoelectric effect UV light was shot at a zinc plate and electron were emitted UV light was shot at a zinc plate and electron were emitted Electrons only jumped when the light was above a threshold frequency Electrons only jumped when the light was above a threshold frequency Light can transfer energy, a matter property Light can transfer energy, a matter property

6. Monochromatic light strikes a metal surface that has a work function of 6.7 x 10 -19 J. Each photon has an energy of 8.0 x 10 -19 J What is the maximum KE of the photoelectrons? What is the maximum KE of the photoelectrons? 1.3 x 10 -19 J 1.3 x 10 -19 J What is this energy in eV? What is this energy in eV? 0.81 eV 0.81 eV

7. E-m radiation of constant frequency incident on a photoemissive material causes the emission of photoelectrons. If the intensity of this radiation is increased, what will happen to the number of the emissions of photoelectrons?

8. Draw a graph of the photocurrent of photoelectrons (Y) vs. Intensity of the incident light (X) What is the relationship between intensity of light and current?

9. How much energy will a blue light with a frequency of 6.0 x 10 14 Hz have? 4.0 x 10 -19 J

10. The wavelength of photon A is greater than that of photon B. Compared to the energy of photon A the energy of photon B is... E = hc/λ

11. The ratio of the energy of a quantum of electromagnetic radiation to its frequency is called:

12. See the handout graph: What is the slope of the line? What is the slope of the line? What is the threshold frequency of metal A? What is the threshold frequency of metal A? Who discovered the property expressed in this graph? Who discovered the property expressed in this graph? What did this discovery prove? What did this discovery prove? Compared to the Work function of B, the W 0 of A is... Compared to the Work function of B, the W 0 of A is...

13. Metal B Monochromatic light hits both metals. Which source will emit photoelectrons with the least energy? Monochromatic light hits both metals. Which source will emit photoelectrons with the least energy?

14. Which color of visible light has the greatest energy per photon?

15. Which phenomenon can only be explained by assuming that light is quantized?

16. Describe the Compton Effect? Light has the ability to transfer momentum Light has the ability to transfer momentum Therefore it has particle properties Therefore it has particle properties

17. As the wavelength of a photon decreases, what happens to its momentum? p = h/λ

18. What is the momentum of a photon of light whose wavelength is 5.0 x 10 -7 -m? 1.326 x 10 -27 kg m/s

19. If the wave properties of a particle are difficult to observe, it is probably due to the particles...

20. What did the following physicists have to say... DeBroglie DeBroglie Matter should have wave characteristics Matter should have wave characteristics Heisenberg Heisenberg Nothing can be certain without and experiment Nothing can be certain without and experiment An electrons position and momentum cannot both be known An electrons position and momentum cannot both be known Schrodinger Schrodinger A cat is alive and dead until looked at. A cat is alive and dead until looked at.

21. The “electric eye” on the gym partition makes use of the photoelectric effect. What other devices make use of this effect?