Which of the following particles is considered the most suitable particle for splitting a heavy nucleus?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Neutron
A neutron carries no charge, so it feels no Coulomb repulsion from the positive nucleus. Even a slow (thermal) neutron can reach and enter a heavy nucleus such as 235U, which then becomes unstable and splits (nuclear fission). Each fission also releases further neutrons, which makes a chain reaction possible.
NCERT (2026-27):
Fission – “… A most important neutron-induced nuclear reaction is fission. An example of fission is when a uranium isotope \( {}^{235}_{92}\mathrm{U} \) bombarded with a neutron breaks into two intermediate mass nuclear fragments
\( \displaystyle {}^{1}_{0}\mathrm{n} + {}^{235}_{92}\mathrm{U} \rightarrow {}^{236}_{92}\mathrm{U} \rightarrow {}^{144}_{56}\mathrm{Ba} + {}^{89}_{36}\mathrm{Kr} + 3\,{}^{1}_{0}\mathrm{n} \qquad (13.10) \)”