5.3.2 gamma, x-rays, and UV light

• Uses of gamma rays

  • medical imaging and therapy
  • astronomy
  • sterilisation
  • food preservation
• Risks of gamma rays

  • extremely penetrating
  • damaging to living tissues and cells
• Gamma rays carry the most energy. We use them to destroy bacteria and tumors
• X-rays - safety precautions

  • exposure to X-rays must be kept low
  • people working with X-rays must shield themselves to prevent exposure
  • to do this, they will place materials (metals or lead) between themselves and the X-rays
• Risks of X-rays

  • highly ionising - they can damage body cells, even in low doses
• Uses of X-rays

  • low-energy X-rays are used for medical and industrial imaging
  • high-energy X-rays can be used to treat cancer
  • also used as security precaution in airports and other places
• X-rays penetrate soft materials like body tissue. Bones are dense materials that absorb X-rays. We can use X-rays to build a shaded image of bones and body tissue
• Fill the gaps

  A) industrial

  B) weapons

  C) ionising

  D) exposure

  
• Risks of Ultraviolet light (UV)

  • too much exposure can cause skin burns, skin cancer, and cataract formations in the eye
• In lamps, UV photons excite (gives energy to) atoms. The atoms then release visible light.
• In sun tanning, UV excites (gives energy to) skin cells. The skin cells then change colour
• Uses of UV light

  • medical and forensic photography
  • air purification
  • disinfection
  • medical therapy
  • can also be used to detect fake bank notes
• UV light is between X-rays and visible light in the electromagnetic spectrum
• Fill the gaps

  A) tissues

  B) penetrating

  C) medical imaging

  D) sterilisation