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

Proton=positron+neutron. what about law of conservation of mass?

  1. Jan 7, 2012 #1
    neutron weighs higher than proton and you add a mass of positron which is around equal to to electron. so mass in right had side is much larger than that is LHS so is it disobeying Law of conservation of mass?
    if it disobeys it and follow law of conservation of mass and energy.(E=mc2) then it doesn't seems to form any bond which causes release of energy and cause this extra mass.
     
  2. jcsd
  3. Jan 7, 2012 #2

    Dale

    Staff: Mentor

    A proton is not composed of a positron and a neutron. I think that you are thinking of β+ decay where a proton can gain energy and decay into a neutron, positron, and neutrino. See: http://en.wikipedia.org/wiki/Beta_decay#.CE.B2.2B_decay

    Note that β+ decay requires energy for exactly the reason you mention, the mass of the products is greater than the mass of the reactants.
     
  4. Jan 7, 2012 #3
    A i have said it does not seem to form an new bond so is this energy given by external source?
     
  5. Jan 7, 2012 #4

    Dale

    Staff: Mentor

    Yes, the external source being the rest of the nucleus containing the decaying proton. See the last two sentences of the section I referenced above.
     
  6. Jan 7, 2012 #5
    thanks DaleSpam for your help.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Proton=positron+neutron. what about law of conservation of mass?
Loading...