Final answer:
Option 3: The energy of electrons striking the output phosphor is primarily converted into light photons as they cause scintillation, which is then detected by devices like photomultiplier tubes.
Step-by-step explanation:
The energy of electrons striking the output phosphor is primarily converted into light photons. When electrons, accelerated by a high voltage, strike the anode in a cathode ray tube (CRT), they transfer their kinetic energy to the atoms of the anode. This energy transfer results in ionized atoms and inner-shell electrons being knocked into higher orbits. As these excited atoms return to their ground state, they emit characteristic x-ray photons as a part of electromagnetic (EM) radiation. Some of these x-ray photons may strike the output phosphor, where they are converted into visible light photons by the process of scintillation, which is then detected by devices like a photomultiplier tube based on the photoelectric effect.
The energy of electrons striking the output phosphor is converted into light photons.
When electrons strike the output phosphor, they transfer their kinetic energy to the phosphor atoms. As the atoms de-excite, they emit light photons as a form of electromagnetic radiation.
These emitted light photons form the basis of the image on the screen in devices such as cathode ray tubes (CRT) and scintillators.