Home | | Physics 12th Std | Discovery of Neutrons

Radioactivity | Nuclear Physics - Discovery of Neutrons | 12th Physics : UNIT 9 : Atomic and Nuclear Physics

Chapter: 12th Physics : UNIT 9 : Atomic and Nuclear Physics

Discovery of Neutrons

In 1930, two German physicists Bothe and Becker found that when beryllium was bombarded with α particles, highly penetrating radiation was emitted.

Discovery of Neutrons

In 1930, two German physicists Bothe and Becker found that when beryllium was bombarded with α particles, highly penetrating radiation was emitted. This radiation was capable of penetrating the thick layer of lead and was unaffected by the electric and magnetic fields. Initially, it was thought as γ radiation. But in the year 1932, James Chadwick discovered that those radiations are not EM waves but they are particles of mass little greater than the mass of the proton and had no charge. He called them as neutrons. The above reaction can be written as

 49Be + 24He → 612C + 01n

where 10n denotes neutron.

Neutrons are stable inside the nucleus. But outside the nucleus they are unstable. If the neutron comes out of the nucleus (free neutron), it decays with emission of proton, electron, and antineutrino with the half life of 13 minutes.

Neutrons are classified according to their kinetic energy as (i) slow neutrons (0 to 1000 eV) (ii) fast neutrons (0.5 MeV to 10 MeV). The neutrons with average energy of about 0.025 eV in thermal equilibrium are called thermal neutron, because at 298K, the thermal energy kT 0.025eV . Slow and fast neutrons play a vital role in nuclear reactors.

Tags : Radioactivity | Nuclear Physics , 12th Physics : UNIT 9 : Atomic and Nuclear Physics
Study Material, Lecturing Notes, Assignment, Reference, Wiki description explanation, brief detail
12th Physics : UNIT 9 : Atomic and Nuclear Physics : Discovery of Neutrons | Radioactivity | Nuclear Physics

Related Topics

12th Physics : UNIT 9 : Atomic and Nuclear Physics


Privacy Policy, Terms and Conditions, DMCA Policy and Compliant

Copyright © 2018-2023 BrainKart.com; All Rights Reserved. Developed by Therithal info, Chennai.