Frequency

The frequency of electromagnetic radiation (light) refers to the number of wave-cycles of an electromagnetic wave that pass a given point in a given amount of time.

  • Frequency is measured in Hertz (Hz) and signifies the number of wave-cycles per second. Sub-units of Hertz enable measurements involving a higher count of wave-cycles within a single second.
  • The frequency of electromagnetic radiation spans a broad range, from radio waves with low frequencies to gamma rays with high frequencies.
  • The wavelength and frequency of light are closely linked. Specifically, as the wavelength becomes shorter, the frequency increases correspondingly.
  • It is important not to confuse the frequency of a wave with the speed at which the wave travels or the distance it covers.
  • The energy carried by a light wave intensifies as its oscillations increase in number and its wavelength shortens.
Radio waves
  • Radio waves have the lowest frequencies among these types of electromagnetic radiation. They typically range from a few kilohertz (kHz) to hundreds of gigahertz (GHz). Radio waves are commonly used for communication purposes, such as radio broadcasting and wireless communication.
Microwaves
  • Microwaves have frequencies higher than radio waves, typically ranging from several gigahertz (GHz) to hundreds of gigahertz (GHz). They are commonly used in microwave ovens, satellite communication, and radar technology.
Infrared radiation
  • Infrared radiation (IR) has frequencies higher than microwaves, ranging from several hundred gigahertz (GHz) to several hundred terahertz (THz). Infrared radiation is associated with heat and is used in various applications, including thermal imaging, remote controls, and infrared spectroscopy.
Visible light
  • Visible light is the range of frequencies that can be detected by the human eye, approximately ranging from 430 terahertz (THz) for red light to 750 terahertz (THz) for violet light. Visible light enables us to perceive colours and is responsible for our sense of vision.
Ultraviolet
  • Ultraviolet (UV) radiation has frequencies higher than visible light, typically ranging from several hundred terahertz (THz) to several petahertz (PHz). UV radiation is known for its effects on the skin and can be harmful in excessive exposure. It is used in applications like sterilization, fluorescence analysis, and tanning beds.
X-rays
  • X-rays have higher frequencies than UV radiation, typically ranging from several petahertz (PHz) to several exahertz (EHz). X-rays have shorter wavelengths and are commonly used in medical imaging, security screening, and industrial inspections.
Gamma rays
  • Gamma rays have the highest frequencies among these types of electromagnetic radiation, typically exceeding several exahertz (EHz). They have the shortest wavelengths and are associated with high-energy phenomena, such as radioactive decay and nuclear reactions. Gamma rays are used in medical treatments, scientific research, and industrial applications.

The frequency of electromagnetic radiation (light) refers to the number of wave-cycles of an electromagnetic wave that pass a given point in a given amount of time.