What do you mean by Radioactivity?

It is a phenomenon of radioactive decay that results in the emission of a huge amount of energy and also the formation of subatomic particles. 

The radioactive elements are unstable heavy elements. They emit radiation decaying themselves into a lighter stable nucleus, along with the formation of subatomic particles. The former atom is known as the parent atom, and the latter atom is known as the daughter atom.

Radioactive decay occurs in the naturally occurring elements as well as artificial isotopes of the atoms. 

The Nature of Radioactive Emissions

When a heavy nucleus decays into lighter nuclei, it emits particles such as the alpha particles, the beta particles, the gamma-ray, and the neutrino. The alpha particles are the positively charged helium nucleus. The beta particles are the negatively charged stream of electrons. Gamma rays are electromagnetic radiations that are very hazardous to human health. 

The beta plus particles are known as the positron. Two or more positron particles combine, and this particle is known as pair annihilation. 

Types of Radioactivity

There are different types of radioactivity. These are classified based on the different types of radiation emitted. 

• Alpha decay: In this type of decay, an alpha particle is given out from a parent atom, and a daughter nucleus is formed. The atomic number of the daughter nucleus is two less than the atomic number of the parent nucleus. As a result, the mass number of the daughter nucleus is four less than the mass number of the parent nucleus. In this type of decay, a tremendous amount of energy (in MeV) is produced. 

For example, when a uranium atom is decayed into polonium and an alpha particle. 

• Beta minus decay: In this type of process, a negative stream of electrons is emitted from an atom. The atomic number of the daughter nucleus is one more than the atomic number of the parent nucleus. However, the mass number of the daughter nucleus remains the same as the mass number of the parent nucleus.
• Gamma decay: Gamma decay never occurs alone. It always takes place along with the alpha or beta decay. In this type of decay, there is neither change in the mass number nor the atomic number of the parent nucleus. It only lowers the energy of the parent nucleus.

What do you mean by Mean Life of a Radioactive Substance?

 The mean life of a radioactive substance is defined as the total lifetime of all the nuclei to the number of nuclei.  

What do you mean by Half-Life of a Radioactive Substance?

The half-life of a radioactive substance is defined as the time duration in which only half of the radioactive substance decays.

Some Naturally Occurring Radioactive Substance

• Uranium
• Radium
• Thorium
• Radon
• Polonium
• Plutonium
• Rubidium
• Technetium
• Promethium
• Francium
• Astatine 

Applications of Radioactivity

• In the medical field: Radioisotopes are widely used for therapeutic purposes. In addition, they have given rise to nuclear medicines. 

• In Industry: Powers and electricity is produced by using radioactive isotopes. They are used to measure the effectiveness of the motor oils. 

Conclusion

This article focuses on the mean life of a radioactive substance. Radioactive substances get decayed by the passage of time into a lighter nucleus, plus the radiations that are emitted during the process. 

Therefore, by going through this article, one can easily understand the above topics. One can clarify its doubts and understand its application in real life.