Which component of a cathode ray tube glows when struck by an electron beam?

Which component of a cathode ray tube glows when struck by an electron beam?

• A. An electron gun
• B. An electron amplifier
• C. A CRT screen
• D. An electron counter

Answer: (C)

The screen glows because the phosphor coating on the CRT face emits light when excited by the incoming electron beam. In a cathode ray tube, electrons are produced by the electron gun, accelerated, and directed to scan across the phosphor-covered screen. When the electrons hit the phosphor, the atoms release photons, producing visible light that forms the image. The other components don’t glow: the electron gun is the source of electrons, not a light-emitting surface; the term “electron amplifier” isn’t a glowing part of a CRT, and an electron counter isn’t part of the display.

The screen glows because the phosphor coating on the CRT face emits light when excited by the incoming electron beam. In a cathode ray tube, electrons are produced by the electron gun, accelerated, and directed to scan across the phosphor-covered screen. When the electrons hit the phosphor, the atoms release photons, producing visible light that forms the image. The other components don’t glow: the electron gun is the source of electrons, not a light-emitting surface; the term “electron amplifier” isn’t a glowing part of a CRT, and an electron counter isn’t part of the display.