Which of the following statement(s) is/are correct ?
2017
Which of the following statement(s) is/are correct ?
- A.
Persistence is the term used to describe the duration of phosphorescence.
- B.
The control electrode is used to turn the electron beam on and off.
- C.
The electron gun creates a source of electrons which are focussed into a narrow beam directed at the face of CRT.
- D.
All of the above
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Correct answer: D
Summary: Each statement is correct. Brief explanations are given below.
Persistence: the duration of phosphorescence — how long a phosphor continues to emit light after the electron beam is removed. In CRTs, persistence affects flicker and motion blur.
Control electrode: the control grid modulates electron flow from the cathode and can turn the beam on or off, thereby controlling screen brightness.
Electron gun: produces the electron source and, with focusing electrodes, forms a narrow beam directed at the CRT face for image formation.
Answer: All of the above — each of the above statements is accurate.