Who among the following is credited with the discovery of neutrons?

J Chadwick

The correct answer is option 1. J Chadwick.

James Chadwick is credited with the discovery of the neutron, a subatomic particle that has no electric charge and is found within the nucleus of atoms. 

Prior to Chadwick's discovery, scientists knew about the existence of two types of particles in the atomic nucleus: positively charged protons and negatively charged electrons. However, it was observed that the mass of the nucleus was greater than the combined mass of the protons it contained. This led scientists to speculate the existence of a neutral particle within the nucleus.

In the early 1930s, James Chadwick, who was working in Ernest Rutherford's laboratory at the Cavendish Laboratory in Cambridge, England, began conducting experiments to investigate the nature of the radiation emitted by beryllium when bombarded with alpha particles.

Chadwick observed that the radiation emitted by beryllium consisted of a highly penetrating neutral radiation. Through careful experiments, he determined that this neutral radiation was composed of particles with approximately the same mass as protons but with no electric charge. Chadwick concluded that these particles were previously unknown and named them neutrons.

The discovery of neutrons was groundbreaking because it provided a more complete understanding of atomic structure. Neutrons play a crucial role in stabilizing atomic nuclei and are essential for nuclear reactions. This discovery paved the way for further advancements in nuclear physics, including the development of nuclear energy and the understanding of nuclear fission and fusion processes.

James Chadwick's discovery of the neutron earned him the Nobel Prize in Physics in 1935 and remains one of the most significant contributions to our understanding of the fundamental building blocks of matter.