Aim: How can we explain the Compton Effect and the DeBroglie Wavelength?

1. Aim: How can we explain the Compton Effect and the DeBroglie Wavelength? The threshold frequency of sodium is 5.6 x 1014 Hz. • Find the work function • If light with a frequency of 8.6 x 1014 Hz strikes it, find the KEmax. Wo = hfo Wo = (6.63 x 10-34 J·s)(5.6 x 1014 Hz) Wo = 3.7 x 10-19 J KEmax = hf – Wo KEmax = (6.63 x 10-34 J·s)(8.6 x 1014 Hz) – 3.7 x 10-19 J KEmax = 1.98 x 10-19 J

2. Remember the Law of Conservation of Momentum? After the collision, energy and momentum are transferred to the car Total energy and momentum are conserved

3. Compton Effect The same effect is observed for photons striking an electron If a photon loses energy, what happens? e-

4. Compton Effect • Named after Arthur Compton • The collision of an x-ray photon and an electron where some energy is transferred to the electron from the photon. • After the collision, the photon has less energy and therefore a higher wavelength, or lower frequency Arthur Holly Compton 1892-1962

5. This proved that photons have momentum and that momentum is conserved

6. Calculate the momentum of an x-ray whose wavelength is 5 x 10-12 m.

7. Calculate the momentum of yellow light.

8. Louis de DeBroglie • If waves have matter properties, then matter must have wave properties 1892-1987

9. Proven by passing electrons through a diffraction grating and developing a diffraction pattern • Matter behaved like a wave

10. DeBroglie Wavelength • Also known as the matter wavelength

11. Calculate the matter wavelength of a 70 kg boy running at 5 m/s

12. Calculate the matter wavelength of an electron moving with a velocity of 2.5 x 105 m/s.