Electromagnetic Waves and Uses of EM Waves

• Electromagnetic (EM) waves


  • All EM waves are transverse waves that transfer energy from a source to an absorber
  • All EM waves travel at the same speed through air or a vacuum
  • EM waves aren't vibrations of particles, they're vibrations of electric and magnetic fields
• Types of EM waves

  • Gamma rays
  • Radio waves
  • Microwaves
  • Infrared
  • Visible light
  • Ultraviolet
  • X-rays
• EM waves form a continuous spectrum over a range of frequencies
• EM waves are generated by a variety of changes in atoms and their nuclei
• Different EM waves are used for different purposes due to their different properties
• Radio waves

  Made by oscillating charges
• How radio waves are produced

  1. Alternating current causes oscillating charges

  2. Oscillating charges produce oscillating electric and magnetic fields (EM waves)

  3. Frequency of waves equals frequency of alternating current

  4. Transmitter object with oscillating charges produces radio waves
• How radio waves are received

  1. Radio waves are absorbed by receiver

  2. Energy from waves causes electrons in receiver to oscillate

  3. Oscillating electrons in receiver circuit generate alternating current
• The alternating current produced in the receiver has the same frequency as the received radio waves