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 * [As half life = 14 min = 14 x 60 sec].

Energy = [Mn – (MP + Me)]u = [(Mnu – Mpu) – Mpu]c2 = [0.00189u – 511 KeV/c2]

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