Final answer:
A scattered photon has lower energy than the incoming primary beam photon because it loses some energy to the particle it scatters off during the interaction.
Step-by-step explanation:
The question you've asked is related to the scattering of photons, specifically in the context of how their energy compares before and after the scattering process. When a photon is scattered, it interacts with another particle, such as an electron, and in this process, it might impart some of its energy to that particle. Therefore, a scattered photon has lower energy than the incoming primary beam photon. This is because when a photon undergoes scattering, like Compton scattering, it transfers part of its energy to the particle it scatters off, effectively losing some of its initial energy.