Electromagnetic wave

Electromagnetic waves are composed of oscillating magnetic and electric fields. So all forms of light within the electromagnetic spectrum can be thought of as vibrations produced as a result of the interaction between an electric field and a magnetic field.

  • There are three principle properties of an electromagnetic wave:
    • Wave velocity (v): The measure of how fast a wave propagate in a given medium. Its unit is meter per second.
    • Wavelength (λ): The distance over which the shape of wave repeats. It depends on the medium a wave travels through. It is measured in meters.
    • Frequency (f): The number of wave-cycles of an electromagnetic wave that pass a given point in a given amount of time. The unit of frequency is Hertz, or one wave per second.
  • An electromagnetic wave carries electromagnetic radiation.
  • Electromagnetic radiation is measured in terms of the amount of electromagnetic energy carried by an electromagnetic wave.
  • Electromagnetic waves can be imagined as synchronised oscillations of electric and magnetic fields that propagate at the speed of light in a vacuum.
  • The energy carried by electromagnetic waves is often simply called radiant energy or light.
  • Electromagnetic waves are similar to other types of waves in so far as they can be measured in terms of wavelength, frequency and amplitude.
  • Electromagnetic radiation can also be described in terms of elementary particles called photons.
  • We can feel electromagnetic waves release their energy when sunlight warms our skin.
  • The position of an electromagnetic wave in the electromagnetic spectrum can be characterized by either its frequency of oscillation or wavelength.
  • The electromagnetic spectrum includes, in order of increasing frequency and decreasing wavelength: radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays and gamma rays.
  • The limit for long wavelengths is the size of the universe itself, while it is thought that the short wavelength limit is in the vicinity of the Planck length.