Question

Ionizing radiation interacts with matter by scattering from electrons and nuclei in the substance. Based on the law of conservation of momentum and energy, explain why electrons tend to absorb more energy than nuclei in these interactions.

a) Electrons have less mass, resulting in larger momentum transfers.

b) Electrons have greater mass, resulting in larger momentum transfers.

c) Nuclei have less mass, resulting in larger momentum transfers.

d) Nuclei have greater mass, resulting in larger momentum transfers.

Answer 1

Electrons absorb more energy than nuclei during ionizing radiation interactions because they have less mass, allowing for larger momentum transfers as per the law of conservation of momentum and energy.

Step-by-step explanation:

Ionizing radiation interacts with matter by scattering from electrons and nuclei in the substance. When considering the law of conservation of momentum and energy, electrons tend to absorb more energy than nuclei due to their significantly lower mass. The correct choice is option a), stating that electrons have less mass, resulting in larger momentum transfers. This is because when a particle (like a photon) interacts with an electron, the ratio of their masses allows a greater portion of the incoming particle's energy to be transferred to the electron, thus imparting significant kinetic energy to it. In contrast, nuclei, which are much more massive, absorb comparably less energy and are less likely to be moved significantly by the encounter.