Some of the X-rays emitted by an X-ray imaging machine are fluorescence X-rays and are formed when individual atoms in the machine undergo radiative transitions. While the mercury atoms in a fluorescent lamp also undergo radiative transitions, those mercury atoms emit ultraviolet light, not X-rays. The reason for this difference is that
A) mercury atoms aren't massive enough to emit X-rays, whereas the atoms in an X-ray machine are.
B) the electrons in the imaging machine atoms experience much larger changes in energy during their radiative transitions than the electrons in the mercury atoms do.
C) the electrons in the imaging machine atoms experience much smaller changes in energy during their radiative transitions than the electrons in the mercury atoms do.
D) the atoms in an X-ray machine are packed together in a solid and can amplify each other's waves much more effectively than the gaseous mercury atoms in a fluorescent lamp can.

Question

Quizplus · Accepted Answer

The difference in the type of radiation emitted (X-rays vs. ultraviolet light) is due to the magnitude of energy changes experienced by the electrons during their radiative transitions. In an X-ray machine, the electrons undergo much larger changes in energy, leading to the emission of X-rays, whereas in mercury atoms, the changes are smaller, resulting in the emission of ultraviolet light.

Some of the X-Rays Emitted by an X-Ray Imaging Machine