velocity of daughter nucleus

Discussion in 'Physics' started by circuit2000, Jun 3, 2007.

  1. circuit2000

    Thread Starter Active Member

    Jul 6, 2006
    33
    0
    1)Determine the maximum possible speed of the daughter nucleus in negative beta decay of a He(6,2) nucleus which is initially at rest.
    I solved in the following way:
    He(6,2) --> Li(6,3) + electron + antineutrino
    The daughter nucleus will have maximum speed when the electron and antineutrino has zero kinetic energy. Applying mass-energy equivalence,
    M(He)c^2 = M(Li)c^2 + K(Li)
    Where M(He)=atomic mass of helium isotope, M(Li)= atomic mass of Lithium isotope,
    K(Li)=Kinetic energy of daughter nucleus
    On simplification I get,
    K(Li)=3.52 MeV
    (1/2)M(Li)v^2=3.52 MeV
    On simplification I get,
    v=1x10^7 m/sec
    But the answer given in my book is 1x10^5 m/sec. Could someone please tell me where I have gone wrong?
     
  2. recca02

    Senior Member

    Apr 2, 2007
    1,211
    0
    i think its because u took ke of electrons as zero (its ok to take that for neutrinos and antineutrinos i believe ) .
    try solving using conservation of momentum and energy.
     
Loading...