electromagnetic waves

• uses of gamma rays


  • sterlisation
  • food preservation
  • astronomy
• risks of gamma rays


  extremely penetrating and so can damage internal tissues and cells
• uses of x-rays


  • low energy: medical and industrial imaging
  • high energy: treating cancer
  • security purposes like detecting weapons
• risks of x-rays


  • highly ionising and so can damage internal cells
  • people should be shielded when dealing with x-rays
• uses of ultraviolet light


  • medical and forensic photography
  • air purification
  • detecting fake bank notes
• risks of ultraviolet light


  • cause skin burns
  • skin cancer
  • cataract formations in the eye
• uses of visible light


  helps us see the world around us
• colours of visible light


  • red
  • orange
  • yellow
  • green
  • blue
  • indigo
  • violet
• uses of infrared radiation


  • TV controls
  • security purposes because it can detect heat
• risks of infrared radiation


  can cause skin burns (at high intensities)
• used of microwaves


  • satellite communications
  • transmit signal from phone mast to phone tower
  • cooking food
• risks of microwaves


  • can be absorbed by the human body because of water
  • always have a shield between microwave and person
• uses of radio waves


  • radio
  • TV communications
• risks of radio waves


  can internally heat tissues (at high intensities)
• speed of electromagnetic waves


  3.0 x 10$^{10}$
• shortest wavelength and highest frequency


  gamma
• longest wavelength and lowest frequency


  radio waves
• characteristics needed to absorb radiation best


  • black surface
  • matte surface
• what type of waves are electromagentic waves?

  transverse