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!

Current from Alpha Particles

  1. Jul 10, 2009 #1
    1. The problem statement, all variables and given/known data
    Assume a steady stream of α particles travels with a constant energy of 20 MeV and carries a current of 2.5 μA.

    a) If the beam is directed perpendicular to a plane target, how many α's will strike this target in 8 seconds?
    b) At any given instant, how many α's are in a 20 cm length of the beam?
    c) Through what electrical potential diffence is it necessary to accelerate each α from rest to bring it to the energy of 20 MeV?

    2. Relevant equations
    ?

    3. The attempt at a solution
    I have absolutely no idea how to solve any of these questions. The only thing I could think to do was find how many protons were in the current by multiplying 2.5E-6 by 8 seconds to give me the amount of Coulombs. I then multiplied that by 6.2415E18 e/C to get the number of elementary charges. I thought this solution may be the answer to part a) but it wasn't. So now I'm lost.

    Any help will be greatly appreciated.
     
  2. jcsd
  3. Jul 10, 2009 #2

    turin

    User Avatar
    Homework Helper

    How many elementary charges are there per alpha?
     
  4. Jul 10, 2009 #3
    There's two protons per alpha particle.
     
  5. Jul 10, 2009 #4

    turin

    User Avatar
    Homework Helper

    It was a hint.
     
  6. Jul 10, 2009 #5
    I don't want to be rude, but that really doesn't help me... I still don't know what to do.
     
  7. Jul 10, 2009 #6

    turin

    User Avatar
    Homework Helper

    If you know how many elementary charges hit the surface, and you know how many elementary charges there are per alpha particle, then ...
     
  8. Jul 10, 2009 #7
    Oh, wow. See, I had thought my entire methodology was incorrect... I didn't realize I was actually close to the answer for part a). Thanks! Now I at least have part a) correct.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Current from Alpha Particles
  1. Alpha particles (Replies: 3)

  2. Alpha particle (Replies: 4)

Loading...