1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Photoelectric effect and photocurrent drop

  1. Nov 23, 2008 #1
    1. The problem statement, all variables and given/known data

    Does the photocurrent drop to zero when a potential across it is equal to the kinetic energy of electrons?, because i found this not to be the case, the photocurrent reached a steady value that didnt decrease further, as i increased the potential across the anode and cathode. I dont understand why this happend?
     
  2. jcsd
  3. Nov 24, 2008 #2

    Redbelly98

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    Was the anode at + or - relative to the cathode?
     
  4. Nov 24, 2008 #3
    anode voltage was increased negatively so electron should be repelled from anode in theory, but for some reason i still was obtaining postive photocurrent, maybe i should have taken much larger negative values for potential, so current would eventually become zero?, however do you think i can extrapolate (with a curve of best fit) to zero current, because my graphs are curving towards zero photocurrent.
     
  5. Nov 24, 2008 #4

    Redbelly98

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    It depends. What wavelength(s) was/were used to generate the photocurrent? How high a voltage did you get to?

    Extrapolating reasonably depends on whether graphing the data generates a straight line. Does it?
     
  6. Nov 24, 2008 #5
    I used yellow, turquoise, green, blue, violet. it isnt ment to generate a straight line, for each frequency, the photocurrent (yaxis) is kind of meant to drop like a 1/x graph when plotted against the potential across the xaxis
     
  7. Nov 24, 2008 #6

    Redbelly98

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    That's weird. I would expect current to be zero if you go high enough in voltage, but I haven't done the experiment.

    Not sure what's going on.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Photoelectric effect and photocurrent drop
  1. Photoelectric Effect? (Replies: 9)

  2. Photoelectric effect (Replies: 1)

  3. Photoelectric effect (Replies: 6)

Loading...