Radioactivity And Nuclear Decay - SS3 Physics Lesson Note

Radioactivity is the process by which an unstable atomic nucleus emits particles and/or energy in the form of electromagnetic radiation, such as gamma rays, or particles, such as alpha and beta particles. This process is known as nuclear decay or radioactive decay.

The three types of nuclear decay are:

Alpha decay: In alpha decay, a heavy, unstable nucleus emits an alpha particle, which is a helium nucleus consisting of two protons and two neutrons. This decreases the atomic number of the nucleus by two and the mass number by four.

Beta decay: In beta decay, a neutron in the nucleus is converted into a proton and an electron. The proton stays in the nucleus, and the electron is emitted as a beta particle. This increases the atomic number of the nucleus by one, while the mass number remains the same.

Gamma decay: Gamma decay occurs when the nucleus emits a gamma ray, which is a high-energy electromagnetic radiation. Gamma decay does not change the atomic number or mass number of the nucleus. Gamma decay is the most penetrating form of radiation.

Radioactivity has both natural and human-made sources, and it has a wide range of applications in fields such as medicine, industry, and research. However, it can also be hazardous to human health and the environment, as exposure to high levels of radiation can cause cancer, genetic mutations, and other health problems.