The number of neutrons emitted when ${ }_{92}^{235} \mathrm{U}$ undergoes controlled nuclear fission to ${…
The number of neutrons emitted when ${ }_{92}^{235} \mathrm{U}$ undergoes controlled nuclear fission to ${ }_{54}^{142} \mathrm{Xe}$ and ${ }_{38}^{90} \mathrm{Sr}$ is