Electromagnetic waves

• Electromagnetic waves


  Transverse waves that transfer energy from the source of the waves to an absorber
• Examples of electromagnetic waves

  • Microwaves
  • Solar light
• Visible light


  • Part of the electromagnetic spectrum
  • Different wavelengths and frequencies
  • Red end has lower frequency and longer wavelength
  • Violet end has higher frequency and shorter wavelength
• Electromagnetic spectrum


  • Radio waves
  • Microwaves
  • Infrared
  • Visible light
  • Ultraviolet
  • X-rays
  • Gamma rays
• The electromagnetic spectrum is a continuous spectrum, the cutoff point between one type of wave and another is not always clear
• Electromagnetic waves do not need a medium to travel in, they can travel through a vacuum
• All electromagnetic waves travel at the same speed in a vacuum, 3 x 10^8 m/s
• Absorption, transmission, and reflection of electromagnetic waves


  Depends on the wavelength of the wave
• Example of absorption and reflection of electromagnetic waves

  • Microwaves are absorbed by foods containing water, but reflected by metals
  • Light waves are absorbed by black surfaces and reflected by shiny metallic surfaces