What term describes the duration that phosphor on a screen remains illuminated after an electron beam is turned off?

The correct term that describes the duration that phosphor on a screen remains illuminated after the electron beam is turned off is persistence. This phenomenon occurs because the phosphor material continues to emit light for a short period after the stimulation (such as from an electron beam) ceases. The persistence of phosphorescent materials varies; some may glow for only a brief moment while others can emit light for a longer duration.

In this context, frequency refers to the number of cycles of a periodic wave occurring in a second, and amplitude refers to the height of the wave or the intensity of the signal. Luminescence, while related to the emission of light, does not specifically address the time duration of the light emission after the excitation source is removed. Thus, persistence is the most accurate term for the duration of illumination in phosphorescent materials.