Correct option is D
An atom emits alpha, beta and gamma particles during radioactivity as unstable atoms try to reach a stable state. As a result, the atom decomposes by emitting a particle. This decaying process continues until the nucleus achieves stability. Mainly three types of radiation are emitted. These include alpha, beta and gamma rays. The atom’s nucleus is responsible for releasing these radiations.
Alpha rays
The alpha rays are the first ones in the list to be positively charged particles. The alpha rays are denoted by α. Its particles are also known as helium atoms. These particles are highly energetic and active helium atoms that comprise mainly two protons and neutrons. The alpha particle has the maximum ionisation power, whereas the minimum penetration power.
If they enter your body due to extremely high ionisation power, they can cause heavy damage to the internal organs. They can ionize several atoms even by a short distance. This happens because radioactive substances, such as alpha, need to be handled only after wearing gloves.
Beta rays
The beta radiation is exceptionally energetic electrons consisting of an electron stream known as the beta particles. The beta rays are denoted by β. Compared with the alpha rays, the beta rays have higher penetrating power but lower ionizing power. Their emission speed is almost equal to the speed of the light. The beta radiation carries a negative charge and bears almost negligible mass. As a result, the electron is mostly likely to be emitted by the nucleus.
Since beta particles have high penetrating power, they can easily travel through the skin. Hence, their contact with the skin can be extremely dangerous and must be avoided. The degradation of radioactive copper is one of the most common examples of beta radiation.
Gamma rays
The Gamma rays consist of ~10 – 12 m wavelength electromagnetic waves. They are exceptionally powerful photons; however, they have significantly less wavelength, which is 0.0005 to 0.1 nm. Gamma rays can be defined as the waves that arise from the high-frequency end of an electromagnetic spectrum, which consists of no mass. As compared to others, gamma rays have higher penetration power. Although they are the highest when it comes to penetrating, they are the least ionizing. Also, it is extremely difficult to stop gamma rays from entering the human body.
Penetration power: the ability of any radiation or particle to pass through matter is called penetrating power.
Alpha particles: since they travel very less in the air, their penetration power is very low and can be easily shielded by a piece of paper
Beta particles: they can pass the paper but can be blocked by aluminum foil
Gamma particles: to stop these a thick dense material of concrete or lead is required
The ionization power is the power to emit an electron from an atom and is directly proportional to the mass of the particle.
