Photoelectric effect
Why is it said that photocurrent doesn't depend on frequency of incident photon in photoelectric effect. Photocurrent should depend on frequency because, more the frequency, more is the kinetic energy of the emitted electron, and hence the electron will reach the collector plate from the emission plate much faster, which ultimately increases current by reducing the time taken to travel "at zero potential"(or can it be at any potential, i don't think so, right?!)?? Plz clarify and explain in depth.
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@Gyro Gearloose
Note for OP
+solved @user1 @user2... to close the thread when your doubt is solved. Mention the users who helped you solve the doubt. This will be added to their stats.That is a lovely question
What we ar talking about is saturation photocurrent
if it was a single electron what you are saying would work
think about it, you have enough photoelectrons to get a max amount of current
to increase that, the speed idea wont work, cos electrons will collide with each other etc.
The faster travel time only affects the transit time of individual electrons, not the rate at which they are generated and collected in a steady state.
does that make sense?
yeah
the speed of individual electrons even in a normal current carrying wire is very slow, on the order of millimeters per second (from the equation
I = neA*v(drift))
its not the speed that's directly responsible for the current
its the collective effect of all the electrons moving togetherwe good? shall we close this out?
Hello sir, actually i had some issue with my phone, so couldn't check out my doubt.. so yeah, i pretty much understood, but the end part that you said was kinda confusing (the faster travel time only affects ...)?? Can you plz briefly elaborate on that part, since you said rate at which the photoelectrons are generated and collected remains same (due to same intensity), but then "rate" again gets associated with time, which terribly confuses me??!! @iTeachChem
yes well intensity is square of current (the ::) to be specific
and yea current is rate of flow of charge, that is correct too :)
one photon = 1 electron. that is a basic assumption too, right?
intensity is of the incident radiation, current is from the generated electrons, does that help?
Sir, from your past explanation, i was thinking why won't faster transit time of electrons affect the current? Bcoz, like you said, the number of photons bombarded on the metal surface per second will generate that much amount electrons, and then under the potential at saturation current, that much only will get reported at the collector plate. But then, what about the transit time?? Can it be the fact that the electrons from the emission plate get reported at the collector plate within a matter of nanoseconds, so increasing the kinetic energy of the electrons(by increasing frequency of photon) would not seriously affect the time ??
Yes sir, i know what stopping potential is..but i will again look into that then:) thank you
The key idea is that all measurements are done in steady state
ie when things do NOT change with time
keep that in mind
https://www.khanacademy.org/science/in-in-class-12th-physics-india/in-in-dual-nature-of-radiation-and-matter/x51bd77206da864f3:experimental-study-of-photoelectric-effect/v/experimental-setup-saturation-current-photoelectric-effect
check these
Thank you! Doubt solved
+fsolved
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