A neutron with kinetic energy K=10 MeV activates a nuclear reaction n+ ¹² C ^9 Be + whose threshold E_ th =6.17 MeV . Find the kinetic energy of the alpha particles outgoing at right angles to the incoming neutron's direction(mark the answer in MeV ). [Take 1 amu =931.1 MeV ]

Step-by-step solution

n+c¹² B e^9+ Let p be the momentum of neutron aligned & p^2 2 m_n = p₂^2 2 m_ + p₁^2 2 m_ B e +Q & p₁ =p, p₁ =p₂ & p^2 2 m_n = p^2 2 m_ B e + p₂^2 2 m_ B e + p₂^2 2 m_ +Q & aligned & [10-10 / 9]=K_ +K_ 4 9 +Q &= 13 K_ 9 +Q & Q=6.17 12 13 aligned & K_ =2.21 MeV aligned