Multiple choice

Which of the following is not true for electron gun as a part of hot cathode ray tube?

  1. Cathode C is indirectly heated by filament F.

  2. The anodes are maintained by means of low tension battery with respect to cathode.

  3. The rate of emission of electrons increases from cathode on increasing filament current.

  4. The brightness of pattern on screen varies by changing negative potential on grid.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In an electron gun, the anodes have a small hole along their axes and they are maintained at a high positive potential with respect to cathode, by means of a high tension battery of about 1000 V. The low tension battery of 6 V is connected by cathode C and filament F. The electrons obtained from cathode are accelerated by a series of cylindrical anodes.

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