Dangers of Electromagnetic Waves (CIE IGCSE Physics: Co-ordinated Sciences (Double Award))

• Excessive exposure to electromagnetic radiation has harmful effects on people
  • As the frequency of the electromagnetic (EM) waves increases, so does their energy
• Beyond the visible part of the spectrum (ultraviolet waves, X-rays and gamma rays), the energy is large enough to ionise atoms
  
  • The higher the frequency, the more ionising the radiation

• The effects of Ionisation also depend on the type of radiation and the size of the dose

Harmful effects of EM radiation

Wave	Danger
Ultraviolet	Damage to surface cells and eyes leads to skin cancer and eye conditions
X-rays and gamma rays	Mutation or damage to cells in the body

Harmful effects of excessive ultraviolet exposure

• Ultraviolet is similar to visible light, except it is invisible to the human eye and carries a much higher energy
• If eyes are exposed to high levels of UV it can cause severe eye damage
  • Good quality sunglasses will absorb ultraviolet, preventing it from entering the eyes

• Ultraviolet can kill cells or cause them to malfunction
  • This can cause premature ageing, and diseases such as skin cancer

  • Sunscreen absorbs ultraviolet light, preventing it from damaging the skin

Harmful effects of excessive X-ray and gamma-ray exposure

• X-rays and gamma rays are the most ionising types of EM waves
  • They can penetrate the body and cause internal damage
  • They can cause the mutation of DNA, causing cancer