There are three main types of ionising nuclear radiation: alpha particles, beta particles, and gamma rays. They differ significantly in their penetrating power:

Alpha particles are relatively heavy and carry a positive charge. They have a low penetrating power and can be stopped by a sheet of paper or even a few centimetres of air. However, if alpha particles enter the body, their high ionization potential can cause significant damage to tissues they pass through.

Beta particles are electrons or positrons. They have a greater penetrating power than alpha particles, able to penetrate a few millimetres of tissue. They can be stopped by a thin sheet of metal like aluminium.

Gamma rays are high-energy electromagnetic radiation. They have the highest penetrating power of the three types and can pass through a significant thickness of materials, such as lead or concrete. They are particularly dangerous because they can penetrate the body and damage cells throughout.

The difference in penetrating power dictates the level of protection required. Alpha particles require only superficial shielding (e.g., a sheet of paper). Beta particles require more substantial shielding (e.g., aluminium). Gamma rays require dense shielding materials like lead or concrete to effectively absorb them.

Ionising nuclear radiation can cause a range of harmful effects on living organisms. These include:

• Cell Death: High doses of radiation can damage cells to the point where they are unable to function and eventually die. This can occur directly through DNA damage or indirectly through the disruption of cellular processes.
• Mutations: Radiation can alter the genetic material (DNA) within cells. These alterations, known as mutations, can be harmful, leading to genetic disorders or an increased risk of diseases.
• Cancer: Mutations caused by radiation can lead to uncontrolled cell growth and the development of cancerous tumours. The increased risk of cancer is a long-term effect of exposure to ionising radiation.
• Acute Radiation Syndrome (ARS): Exposure to very high doses of radiation within a short period can cause ARS, leading to a range of symptoms including nausea, vomiting, hair loss, and damage to the bone marrow and immune system. This can be fatal.

Explanation:

• Alpha Particles: Alpha particles are relatively heavy and have a double positive charge. They interact strongly with matter and are easily stopped by a thin sheet of paper or even the outer layer of skin.
• Beta Particles: Beta particles are electrons or positrons and are lighter and more penetrating than alpha particles. They can be stopped by a thin sheet of plastic or aluminum.
• Gamma Rays: Gamma rays are high-energy photons and are the most penetrating type of ionising radiation. They require dense materials like lead or thick concrete to be effectively shielded. The shielding material needs to be dense enough to absorb or scatter the gamma rays.