Question

Tritium is an isotope of hydrogen whose nucleus Triton contains $2$ neutrons and $1$ proton. Free neutrons decay into $p+\overline{e}+\overline{\nu }$ . If one of the neutrons in Triton decays, it would transform into ${}_2^3$He nucleus. This does not happen. This is because

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

Answer 1

The correct option is A Triton energy is less than that of a $H{e}^3$ nucleus.

Given, the nucleus of Tritium ${(}_1{H}^3)$ contains 1 proton and $2$ neutrons.

When a neutron decay as $n\to p+\overline{e}+\overline{v}$ , the nucleus of Tritium may have $2$ protons and one neutron, i.e., tritium will transform into ${}_{2}H{e}^3$ ($2$ protons and $1$ neutron).

Binding energy of ${}_1{H}^3$ is much smaller than ${}_{2}H{e}^3$.

So, transformation is not allowed energetically.

Final answer: (a)