Multiple choice

When can a steady bright spot be seen on the screen on the deflecting system in a hot cathode ray tube?

  1. When the electron beam strikes the centre of the screen

  2. When no potential difference is applied across the pairs of plates

  3. When there is no fluorescence on the screen

  4. Both (1) and (2)

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

When no potential difference is applied across the pairs of plates, the electrons beam strikes the centre of the screen and a steady bright spot is seen due to fluorescence on the screen on the deflecting system in a hot cathode ray tube.

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