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Question
When stopping potential is applied in an experiment on photoelectric effect, no photoelectric is observed. This means that
Options
the emission of photoelectrons is stopped
the photoelectrons are emitted but are re-absorbed
the photoelectrons are accumulated near the collector plate
the photoelectrons are dispersed from the sides of the apparatus
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Solution
the photoelectrons are emitted but are re-absorbed by the emitter metal
In an experiment on photoelectric effect, the photons incident at the metal plate cause photoelectrons to be emitted. The metal plate is termed as "emitter". The electrons ejected are collected at the other metal plate called "collector". When the potential of the collector is made negative with respect to the emitter (or the stopping potential is applied), the electrons emitted from the emitter are repelled by the collector. As a result, some electrons go back to the cathode and the current decreases.
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RELATED QUESTIONS
Use the same formula you employ in (a) to obtain electron speed for an collector potential of 10 MV. Do you see what is wrong? In what way is the formula to be modified?
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