1. Compton Effect and Matter Waves
Physics 12

2. Compton Effect
The Compton Effect deals with a photon that is incident upon an electron at rest
Following the collision, the photon is scattered at an angle as is the electron
Since the photon has less energy than the incident photon, it must have a lower frequency

3. Compton Effect

4. Compton Effect
Since we know that in a collision momentum must be conserved and the scattered electron has a momentum, the incident photon must also have momentum
This leads to the equation:

5. Compton Effect Example:
Calculate the momentum of a photon of light that has a frequency of 5.09 x 1014 Hz.

6. Photoelectric Effect vs. Compton Effect
In the photoelectric effect, the photons have only a few eV of energy, whereas in the Compton Effect, the photons have more than 1000 times greater energy and a smaller wavelength

7. Photoelectric Effect vs. Compton Effect
In the photoelectric effect, the incident photons kick electrons completely out of the material and the photons are absorbed in the material while the electrons are detected and studied, whereas in the Compton Effect, the incident photons just knock the electrons out of their atoms (but not necessarily out of the material) and then the photons are detected and studied.

8. Matter Waves
If a photon can have both wave and particle like nature, it stands to reason that a particle can also have a wave- like nature
de Broglie determined the wavelength of matter waves using the following equation:

9. Matter Waves Example: Determine the wavelength of the following:
You travelling in a car at 100km/h
An electron orbiting the nucleus at 0.9c
Are either of these wavelengths significant?

10. Verifying Matter Waves
In order to demonstrate that matter (like electrons) have wavelike behaviour, it must be possible to show that they will have interference patterns
von Laue and Bragg developed an X-ray diffraction technique that displays these patterns

12. Wave-Particle Duality
Within 30 years of Planck’s presentation of quantization, the particle nature of light and wave-like behaviour of subatomic particles had been accepted
However, the previous theories of Newton and Maxwell were not abandoned meaning that everything has the ability to act as a particle and a wave