Magnetism and magnetic fields Study Guide

Ultraviolet (UV) radiation, X-rays, and gamma rays are all forms of electromagnetic radiation that carry significant energy. Unlike visible light or radio waves, these higher-frequency radiations possess enough energy to be ionising. Ionisation is the process by which an atom or molecule gains or loses an electron, acquiring a net electrical charge. When ionising radiation interacts with human tissues, it can strip electrons from atoms and molecules within cells. This process can break chemical bonds, leading to damage to vital cellular components such as DNA. Damage to DNA can cause mutations, which may lead to uncontrolled cell growth, characteristic of cancer. Even if cells are not immediately transformed into cancerous cells, severe damage can lead to cell death, causing conditions like radiation burns (from high doses of X-rays or gamma rays) or premature skin ageing and cataracts (from chronic UV exposure).

UV radiation, specifically UVA and UVB, is primarily absorbed by the skin and eyes. Prolonged exposure can damage skin cells, leading to sunburn, premature skin ageing, and increased risk of skin cancer (melanoma and non-melanoma types). In the eyes, UV can contribute to the formation of cataracts, clouding the lens and impairing vision. X-rays and gamma rays are much more penetrating. X-rays are widely used in medical imaging because they can pass through soft tissues but are absorbed by denser materials like bone, providing internal images. However, even at diagnostic doses, repeated exposure carries a small risk. Gamma rays are often associated with radioactive decay and nuclear processes; they are the most penetrating and can damage cells deep within the body, increasing the risk of various cancers and acute radiation sickness at high doses. The hazard depends on the type of radiation, the dose received, and the duration of exposure.