1. Limited time only! Sign up for a free 30min personal 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 units

  1. May 11, 2016 #1
    1. The problem statement, all variables and given/known data
    In a photoelectric experiment, a stopping potential of 2.70 eV is measured when ultraviolet light of wavelength 380 nm is incident on the metal. If blue light of wavelength 440 nm is used, what is the new stopping potential in eV?

    2. Relevant equations

    3. The attempt at a solution
    I think i understand how to do this problem (qV = hc/λ - work function) but am very confused as they have given and ask for the stopping potential in eV. I thought that eV was a unit of energy and that stopping potential (as it is a voltage) is given by the units V. How can the units of a potential be eV?
  2. jcsd
  3. May 11, 2016 #2


    User Avatar
    Science Advisor

    You're right. The stopping potential should really be measured in V, not eV. But since it is electrons you are stopping, people sometimes get sloppy and refer to electron energy (in eV) rather than the potential (in V).
  4. May 11, 2016 #3
    So i should give the answer for the energy and not the potential?
  5. May 11, 2016 #4


    User Avatar
    Science Advisor

    The numerical results should be the same. I would five the answer in V, and explain that the question is really incorrect, since potentials are measured in V.
  6. May 11, 2016 #5
    ok thank you very much!
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted

Similar Discussions: Photoelectric effect units
  1. Photoelectric Effect (Replies: 2)

  2. Photoelectric Effect (Replies: 2)

  3. Photoelectric effect (Replies: 6)