Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Maximum velocity of electrons?

  1. May 9, 2010 #1
    i've been trying to figure out this problem..

    The longest wavelength of light that causes electrons to be ejected from the surface of a copper plate is 243 nm. What is the maximum velocity of the electrons ejected when light of wavelength 200. nm shines on a copper plate?

    the answer is 6.22 × 105 m/s

    any ideas?
  2. jcsd
  3. May 10, 2010 #2
    Read about photoelectric effect.


    Where φ is the work function, the lowest energy that must be supplied to tear off an electron, and hf>φ.
  4. May 10, 2010 #3


    User Avatar
    Science Advisor

    Read the forum rules!
    This isn't the correct board for homework problems. And you should show some attempt to having solved the problem.
  5. May 10, 2010 #4
    thank you.. but how can i relate this to the wavelength concept?
    this is not a homework problem.. it is an old exam question..

    i would appreciate any additional information..
  6. May 10, 2010 #5
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Threads - Maximum velocity electrons Date
Diffusion velocity Dec 4, 2017
Maximum number of hydrogen bonds Oct 26, 2015
Maximum work can be obtained from reversible process ? Dec 2, 2014
Maximum conjugate base Dec 26, 2013
Proof of maximum no. of electrons in a shell Apr 16, 2013