Which one of the following particles in the nucleus of an atom was discovered by J. Chadwick?

Question

Question

This question was previously asked in

NDA-I (GAT) Official Paper (Held On: 13 Apr, 2025)

Answer 1

CONCEPT:

Discovery of the Neutron

In 1932, James Chadwick discovered the neutron, a subatomic particle present in the nucleus of an atom.
The neutron is electrically neutral, meaning it has no charge, and its mass is almost equal to that of a proton.
Chadwick's discovery was essential in understanding the atomic nucleus and led to advancements in nuclear physics, including nuclear fission and the development of atomic energy.

EXPLANATION:

Before Chadwick's discovery, the nucleus of an atom was thought to consist only of protons.
However, the atomic mass of many elements was found to be higher than what could be explained by the number of protons alone.
Chadwick conducted experiments by bombarding beryllium with alpha particles, which resulted in the emission of a neutral radiation that could not be explained by existing theories.

He concluded that this radiation consisted of previously unknown particles, which he named neutrons.

Therefore, the particle in the nucleus of an atom discovered by J. Chadwick is the neutron.