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!

Homework Help: De Broglie wavelength, velocity of electron

  1. Nov 30, 2008 #1
    1. The problem statement, all variables and given/known data

    Question 1) Calculate the de Broglie wavelength of a neutron (mn = 1.67493×10-27 kg) moving at one fiftieth of the speed of light (c/50).

    Question 2) Calculate the velocity of an electron (me = 9.10939×10-31 kg) having a de Broglie wavelength of 225.7 pm.

    2. Relevant equations

    Wavelength of a particle = Plancks constant/(mass)(velocity)
    Plancks constant= 6.626068 x 10^-34
    I know this, and it should be plug and chug but my answer is always wrong...any help would be greatly appreciated!

    3. The attempt at a solution
  2. jcsd
  3. Nov 30, 2008 #2
    I got..

    1) 2.64*10^-15
    2) 3.22*10^6 m/s

    what did you get?
  4. Mar 17, 2011 #3
    Plug it into


    n= proton number
    h= 6.62 x 10^-34
    m= e- mass 9.11 x 10^-31 m
    r= Bohr radius 5.2 x 10^-11 m
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook