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

Force of a ray

  1. Aug 17, 2014 #1
    I don't know much thing about rays. When I was studying Rutherford experiment, I saw that nucleus scattered the alpha rays with Coulomb forces, and naturally the opposite forces effect the nucleus. So do the nucles of atom moves to the direction of alpha rays' first direction?
  2. jcsd
  3. Aug 17, 2014 #2


    User Avatar

    Staff: Mentor

    Yes, the nucleus recoils slightly. We can take this into account by using the "reduced mass" of the alpha particle instead of the actual mass, in our calculations.

  4. Aug 18, 2014 #3


    User Avatar
    Science Advisor
    Education Advisor

    Yes! And, thanks to conservation of momentum, you are able to reconstruct what the nucleus does based on what you measure - this comes up quite often in nuclear physics. In the case of the Geiger–Marsden experiments (aka the Rutherford experiment - Rutherford's students did all the work here), the mass of the alpha particle is small compared to the mass of the gold nucleus so you can safely disregard the recoil of the nucleus - the answer won't change much.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook