electromagnetic spectrum

• Electromagnetic (EM) waves


  Transverse waves

  
• What EM waves transfer

  Energy as radiation from the source of the waves to an absorber

  
• What EM waves travel through

  They can travel through a vacuum

  
• Speed of EM waves n a vacuum or air

  300,000,000 metres per second (m/s)
• Electromagnetic spectrum


  A continuous spectrum of electromagnetic waves that are grouped in terms of their wavelength and their frequency

  
• EM spectrum in order of increasing frequency

  Radio, microwave, infrared, visible light, ultraviolet, X-rays and gamma rays

  
• EM spectrum in order of increasing wavelength

  Gamma rays, X-rays, ultraviolet, visible light, infrared, microwave and radio

  
• Visible light spectrum


  Contains all the frequencies that can be detected by the human eye

  
• Uses of radio waves

  Communication such as television and radio

  
• Uses of microwaves


  Cooking food and for satellite communications

  
• Uses of infrared


  Electrical heaters, microwave ovens, and infrared cameras which can detect people in the dark

  
• Uses of visible light

  Fibre optic communications

  
• Uses of ultraviolet light

  Tanning equipment, energy-efficient lamps

  
• Uses of X-rays


  X-ray photos are used to help identify broken bones

  
• Uses of gamma rays

  Sterilising food and medical equipment

  
• (higher-tier only)

  Producing radio waves

  Radio waves can be produced by oscillations from an alternating current in electrical circuits

  
• (higher-tier only)

  Absorbing radio waves

  Radio waves can themselves produce oscillations and induce an alternating current in an electrical circuit when they are absorbed