During radioactivity, particles like alpha, beta & gamma rays are emitted by an atom, due to unstable atom trying to gain stability. Hence, the atoms eventually decay by emitting a particle that transforms when they are unstable and transforms the nucleus into a lower energy state. This process of decaying continues till the nucleus attains a stable stage.
There exist three major types of radiations emitted by the radioactive particles namely:
These radiations are released from the nucleus of an atom. Their behavior differs from one another, though all the three causes some ionization and carry some penetration power. Let’s discuss the properties of beta, alpha and gamma one by one.
Alpha rays are the positively charged particles. Alpha-particle is highly active and energetic helium atom that contains two neutrons and protons. These particles have the minimum penetration power and highest ionization power. They can cause serious damage if get into the body due to their high ionization power. They are capable of ionizing numerous atoms by a short distance. It is due to the fact that the radioactive substances that release alpha particles are required to be handled after wearing rubber gloves.
Beta particles are extremely energetic electrons that are liberated from the inner nucleus. They bear negligible mass and carry the negative charge. A neutron in the nucleus splits into a proton and an electron on the emission of a beta particle. Hence, it is the electron that is emitted by the nucleus at a rapid pace. Beta particles have a higher penetration power when compared to alpha particles and can travel through the skin with ease. Beta particles can be dangerous and any contact with the body must be avoided, though their ionization power is low.
The waves arising from the high-frequency end of the electromagnetic spectrum that has no mass are known as gamma rays. They hold the highest power of penetration. They are the most penetrating but least ionizing and very difficult to resist them from entering the body. The Gamma rays carry a large amount of energy and can also travel via thick concrete and thin lead.
The below table describes the characteristics of beta, alpha and gamma radiations and compares the masses and charges of the three rays.
|Nature||Positive charged particles, 2He 4 nucleus||Negatively charged particles (electrons).||Uncharged ?~0.01a, electromagnetic radiation|
|Mass||6.6466 × 10–27 kg||9.109 × 10–31 kg||0|
|Range||~10 cm in air, can be stopped by 1mm of Aluminium||Upto a few m in air, can be stopped by a thin layer of Aluminium||Several m in air, can be stopped by a thick layer of Lead|
|Natural Sources||By natural radioisotopes e.g.92U236||By radioisotopes e.g.29Co68||Excited nuclei formed as a result of Gamma decay|
Stay tuned with Byju’s to learn more about characteristics of alpha, beta and gamma rays along with their differentiation and common features.