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Electric Current through Gases — Physics STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 SciencePhysicsElectric Current through Gases1 Mark
Question
The plate current in a diode is zero. It is possible that:
  1. The plate voltage is zero.
  2. The plate voltage is slightly negative.
  3. The plate voltage is slightly positive.
  4. The temperature of the filament is low.
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Answer

  1. The plate voltage is zero.
  2. The plate voltage is slightly negative.
  3. The plate voltage is slightly positive.
  4. The temperature of the filament is low.

Explanation:

The plate current varies directly with the plate voltage. Therefore, if the plate voltage is zero, the plate current is also zero. Due to the same reason, if the plate voltage is negative, the plate current will be zero. Now, if the plate is slightly positive, then it may be the reason that the plate voltage is not able to reduce the effect of space charge. Hence, the current may be zero. Now, as the temperature of the filament is low, it will not be able to emit electrons and the resulting plate current will be zero. Hence, all the options are possible.

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