Uses and Hazards of Electromagnetic Waves — AQA GCSE Physics

Different regions of the EM spectrum have different uses, and the higher-frequency waves can be hazardous.

Uses across the spectrum

• Radio waves — broadcasting and communications.
• Microwaves — satellite communications, cooking.
• Infrared — heating, cooking, thermal imaging, remote controls.
• Visible light — seeing, fibre-optic communications, photography.
• Ultraviolet — energy-efficient lamps, tanning, security marking.
• X-rays — medical imaging of bones, security scanners.
• Gamma rays — sterilising equipment and food, treating cancer.

Why some waves are hazardous

The higher-frequency EM waves carry more energy and are ionising — they can damage cells and DNA:

• Ultraviolet can cause skin ageing and skin cancer, and damage the eyes.
• X-rays and gamma rays are ionising and can cause mutation of genes and cancer.

The lower-frequency waves (radio, microwave, infrared) are non-ionising and generally less harmful, though microwaves can heat body tissue.

Radiation dose

Radiation dose (measured in sieverts, Sv) is a measure of the risk of harm from exposure to ionising radiation. Medical staff and patients limit their exposure.

Exam tips

• Match each EM region to its uses.
• The ionising (dangerous) waves are UV, X-rays and gamma rays.
• UV → skin cancer; X-rays/gamma → gene mutation and cancer.
• Radiation dose is measured in sieverts.