Question

A free neutron beta-decays to a proton with a half-life of 14 minutes, (a) What is the decay constant ? (b) Find the energy liberated in the process.

Answer 1

In →P + e^–

We know : Half life = 0.6931 /λ (Where λ = decay constant).

Or λ = 0.6931 / 14x60 = 8.25 x 10^–4 S [As half life = 14 min = 14 x 60 sec].

Energy = [M_n – (M_P + M_e)]u = [(M_nu – M_pu) – M_pu]c² = [0.00189u – 511 KeV/c²]

= [1293159 ev/c² – 511000 ev/c²]c² = 782159 eV = 782 Kev.