A beta particle is emitted in the following decay scheme

${}^{12}\mathrm{N}\to {{}^{12}\mathrm{C}}^{*}+{\mathrm{e}}^{+}+\mathrm{v}$

${{}^{12}\mathrm{C}}^{*}\to {}^{12}\mathrm{C}+\gamma \left(4.43 \mathrm{MeV}\right)$

If the atomic mass of ${}^{12}\mathrm{N}$ is $12.018613 \mathrm{u}$, then the maximum kinetic energy of beta particle emitted, in ${}^{12}\mathrm{N}\to {}^{12}\mathrm{C}+{\mathrm{e}}^{+}+\mathrm{v}+\gamma \left(4.43 \mathrm{MeV}\right)$ is close to $\left[{\mathrm{m}}_{\mathrm{e}}=0.511\frac{\mathrm{MeV}}{{\mathrm{c}}^2}\right]$