Question

Tritium is an isotope of hydrogen whose nucleus Triton contains 2 neutrons and 1 proton. Free neutrons decay into $p+\bar{e}+\bar{v}$. If one of the neutrons in Triton decays, it would transform into $He ^{3}$ nucleus. This does not happen. This is because

• A. Triton energy is less than that of a $He ^{3}$ nucleus
• B. The electron created in the beta decay process cannot remain in the nucleus
• C. both the neutrons in trition have to decay simultaneously resulting in a nucleus with 3 protons, which is not a $He ^{3}$ nucleus
• D. because free neutrons decay due to external perturbations which is absent in a triton nucleus

Answer 1

Answer: (A)

Tritium $\rightarrow{ }_{1} H ^{3}$. The nucleus contains 1 proton and 2 neutrons. If one neutron decays $n \rightarrow p+ e ^{-}+\bar{v}$, the nucleus may have 2 protons and one neutron, i.e., tritium will transform into ${ }_{2} He ^{3}$ (with 2 protons and one neutron). But this does not happen because triton energy is less than that of ${ }_{2} He ^{3}$ nucleus, i.e., transformation is not allowed energetically.