Dangers of Electromagnetic Waves (Cambridge O Level Physics)

• As the frequency of electromagnetic (EM) waves increases, so does the energy
• Beyond the visible part of the spectrum, the energy becomes large enough to ionise atoms
• As a result of this, the danger associated with EM waves increases along with the frequency
  • The shorter the wavelength, the more ionising the radiation
  • Although the intensity of a wave also plays a very important role

Ionising Region of Electromagnetic Spectrum

Ultraviolet, X-rays and gamma rays can all ionise atoms

• Because of ionisation, ultraviolet waves, X-rays and gamma rays can have hazardous effects on human body tissue
  • The effects depend on the type of radiation and the size of the dose

• They can damage cells and cause mutations, making them cancerous

• In general, electromagnetic waves become more dangerous the shorter their wavelength
  • For example, radio waves have no known harmful effects whilst gamma rays can cause cancer and are regarded as extremely dangerous

• The main risks associated with electromagnetic waves are summarised in the table below:

Dangers of EM Waves Table

Wave	Danger
Radio	No known danger
Microwave	Possible heat damage to soft tissues and internal organs
Infrared	Skin burns
Visible light	Eye damage
Ultraviolet	Eye damage Sunburn Skin cancer
X-rays	Kills cells Mutations Cancer
Gamma rays	Kills cells Mutations Cancer