Question

Choose the option that best explains which Compton scattering experiment more clearly demonstrates the particle nature of electromagnetic radiation: a photon colliding with an electron or a photon colliding with a proton? The photon‑proton collision, because the diameter of an electron is much smaller than the diameter of a proton so it is difficult to get Compton scattering to occur with an electron as the target. Neither experiment is better at demonstrating the particle nature of electromagnetic radiation. The Compton wavelength depends only on the energy of the incoming photon, not on the choice of the target particle. The photon‑electron collision, because the resulting Compton wavelength is approximately 2000 times larger than from a photon‑proton collision, so the resulting change in electron energy is easier to detect. The photon‑proton collision, because the resulting Compton wavelength is approximately 2000 times larger than from a photon‑electron collision, so the resulting change in photon energy is easier to detect. The photon‑electron collision, because the resulting Compton wavelength is approximately 2000 times larger than from a photon‑proton collision, so the resulting change in photon energy is easier to detect.

Answer 1

The shift in the wavelength of the photon after scattering is given by:

this is inversely proportional to the mass and since the mass of an electron is approximately 2000 times less than mass of a proton, the Compton wavelength is approximately 2000 times larger than from a photon-proton collision which makes it easier to detect the change for a photon-electron collision. The reason why it shows the particle nature of electromagnetic radiation is that the interaction between an electron and a photon can be modeled as an elastic collision where the scattered photon will loose some of its energy to the electron which increases its wavelength.