By applying stopping potential, does the photoelectric effect cease to occur or does the photoelectric effect occur and the electron does get emitted and with zero kinetic energy?

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In a vacuum photodiode, which I believe is your context, the photocathode emits photoelectrons regardless of the anode potential. However, if anode potential exceeds the stopping potential, the photoelectron cannot reach the anode and is repelled back to the cathode.

  • $\begingroup$ I think at stopping voltage,the photoelectron cannot reach the anode as K.E(max)=stopping voltage,hence I think exceeding the stopping potential to stop electron reaching the anode is not needed.only stopping voltage is enough. $\endgroup$ Aug 5 at 16:13
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    $\begingroup$ @hsdfasdafhakdfhasiog In a real experiment, you cannot set the potential exactly, so in practice it's either greater than or less than the stopping potential. $\endgroup$
    – John Doty
    Aug 5 at 16:20
  • $\begingroup$ Are you trying to say that in theory the photoelectron stops reaching the anode at stopping voltage(exactly) but in real experiment it is set higher than exact value,because in practice we cannot set exact value ? $\endgroup$ Aug 5 at 16:31
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    $\begingroup$ @hsdfasdafhakdfhasiog Yes. Also, in theory, the photocurrent declines to zero at the stopping voltage, but it's impossible in practice to tell if it is really zero. $\endgroup$
    – John Doty
    Aug 5 at 16:54

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