Photons interact with matter through three main processes: the photoelectric effect where photons eject electrons from atoms, Compton scattering where photons collide with and transfer energy to electrons, and pair production where a photon transforms into an electron and positron pair near a nucleus. Photons are electromagnetic radiation that are massless, electrically neutral particles that travel at light speed and can be stopped by interacting with molecules in matter.

2. Interaction of Photons with
Matter

3. Photoelectric Effect
Compton Scattering
Pair Production

4. Photons
• Electromagnetic radiation
• Massless
• Electrically neutral
• At the speed of light
• Stopped (blocked) by Molecules
• Interact with matter

5. Photoelectric Effect

6. Compton Scattering

7. Pair Production

8. Pair Production