The light given off by the phosphor during exposure to the electron beam is known as

The correct answer is Fluorescence.

Key Points

• Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation.
  • It is a form of luminescence.
  • In a cathode ray tube (CRT) or other similar devices, when the phosphor coating is struck by the electron beam, it emits visible light through the process of fluorescence.
  • This emission of light occurs almost instantaneously with the exposure to the electron beam.
  • Fluorescence ceases almost immediately when the excitation source (electron beam) is removed.
  • This characteristic makes it suitable for applications requiring quick response times.

Additional Information

• Phosphorescence, on the other hand, involves a delayed emission of light and continues to glow even after the excitation source is removed.
• Persistence refers to the duration the screen continues to emit light after the electron beam has moved on.
• Retracing is the process where the electron beam returns to the beginning of the next line or frame in a CRT display.