Which of the following statements about photoelectric absorption is NOT correct?

• A. It ejects a free electron from the atom
• B. It can result in emission of a characteristic photon
• C. It results in significant scattered photon production
• D. It is more likely at lower energy than at higher energy

Answer: (C)

Photoelectric absorption is the process where an incoming photon is completely absorbed by an atom, transferring all of its energy to eject a bound electron (a photoelectron). The energy of that ejected electron is the photon energy minus the binding energy of the electron. After the vacancy is created, the atom can relax as electrons move to fill the gap, which can emit a characteristic x-ray photon (or sometimes an Auger electron).

This process does eject a free electron, and it can lead to emission of characteristic photons when de-excitation occurs. It is more probable at lower photon energies and in higher-Z materials. However, this process does not produce significant scattered photons—that behavior is characteristic of Compton scattering, where photons are deflected with partial energy transfer.

So the statement about significant scattered photon production is not correct.