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Electromagnetic Radiations : Definition, Characteristics, & FAQs

Jul 18, 2022


At first, magnetism and electricity were thought to be two independent forces. Later, in 1873, Scottish physicist James Clerk Maxwell created the combined theory of electromagnetism. Electromagnetic radiation, or EM radiation, is created by electromagnetic fields. Television waves, microwaves, gamma rays, radio waves, X-rays, gamma rays, X-rays, and other types of electromagnetic radiation are all around us and are forms of energy. In this article, we’ll talk about electromagnetic radiation’s definition and its characteristics.

What is Electromagnetic Radiation: Electromagnetics Theory

Earlier magnetism and electricity were assumed to be different forces. However, a comprehensive theory of electromagnetism was created in 1873 by Scottish physicist Clerk Maxwell. Its research focuses on the interactions between electrically charged particles and the magnetic field. The points listed below provide information on the primary electromagnetic interactions.

  • Magnetic poles are similar to electric charges; they are found in pairs that resist and attract one another.
  • There is an opposite relation between the square distance of a particle’s force of attraction and repulsion.
  • A magnetic field formation occurs when an electric field is in motion.
  • An electric wire with a current establishes a magnetic field whose orientation is determined by the current flow.

Electromagnetic Radiation Definition

What is electromagnetic radiation? It is a type of energy created by oscillating magnetic and electrical disturbances or by the motion of electrically charged particles travelling through a vacuum or substance. These combined magnetic and electrical waves go perpendicular to each other since the electric and magnetic fields are at right angles, causing the disturbances. Photons, bunches of light energy that move at the velocity of light as quantum harmonic waves, are the byproducts of electron radiation. The electromagnetic spectrum is then used to categorise this energy depending on its wavelength. These magnetic and electric waves have certain properties, such as amplitude, wavelength, and frequency, and they move perpendicularly.

Thus, it is possible to define electromagnetic radiation as a type of energy created by electrically charged particles moving through a vacuum or matter, as well as by oscillating electric and magnetic disturbance. The combined waves travel perpendicular to both the electric and magnetic oscillating fields causing the disturbance, which is caused by the electric and magnetic fields coming together at a 90° angle.


All electromagnetic radiation has the following general characteristics:

  • Electromagnetic radiation can pass through a vacuum or empty spaces. Almost all other waves should pass through a substance to propagate. For instance, sound waves must pass through a solid, liquid, or gas to be heard.
  • The speed of light remains constant at all times. (Lightning speed: 2..99792458 x 108 m s-1)
  • Wavelengths are calculated as the separation between crests and troughs. Typically, it is identified by the Greek letter λ.

Electromagnetic Waves and their Characteristics



The wave’s amplitude is the distance between its peak vertical displacement and its centre. It gauges the strength of an oscillation in a specific wave. Amplitude is generally the length (height) of the wave. Higher amplitude corresponds to more energy, whereas lower amplitude corresponds to less energy. Amplitude is significant because it conveys a wave’s brightness or intensity concerning other waves.



Wavelength ( λ ) is the distance of one complete oscillation cycle. Longer wavelength waves, like radio waves, have a lower energy content; for this reason, humans can turn on the radio without suffering any negative effects. The higher energy waves with shorter wavelengths, like x-rays, can harm the body. As a result, when having x-rays, lead aprons are used to shield the bodies from dangerous radiation. This relationship between wavelengths is described by:

c = λv 



  • c = speed of light,
  • λ = wavelength, and
  • ν = frequency

Higher frequency equates to higher energy, and higher frequency equates to a shorter wavelength. Wavelengths are significant because they identify the type of wave being studied.



Point to Remember


Amplitude describes the strength of the light, while wavelength describes the sort of light.


Frequency refers to the total number of cycles per second, denoted as sec-1 or Hertz (Hz). Energy and frequency are directly correlated, and frequency can be expressed as:

E = hv


  • E = energy
  • h = Planck’s constant (having a value of 6.62607 x 10-34 J)
  • v = frequency


A period (T) refers to the total time taken by a wave to transit one wavelength. It is calculated in seconds.


The general definition of wave velocity is classified as:



  • v = frequency

In a vacuum or space, the speed of an electromagnetic wave is 2.99 108 m/s or 186,282 miles per second.

Electromagnetic Spectrum

The frequency of a wave rises as its wavelength reduces, and vice versa as its wavelength grows. When electromagnetic energy is produced, the frequency and wavelength decrease as the energy level rises. The electromagnetic spectrum is then used to categorise electromagnetic radiation according to its frequency or wavelength. The electromagnetic spectrum depicts the various types of electromagnetic radiation, including microwaves, radio waves, visible light, infrared waves, ultraviolet radiation, gamma rays and X-rays. The visible light spectrum is the region of the electromagnetic spectrum that we can observe.

Electromagnetic Spectrum

Types of Electromagnetic Radiations

Radio Waves: The wavelength of radio waves is roughly 103 m. As the name suggests, TV broadcasts, radio broadcasts, and even cellular phones transmit radio waves. The energy levels of radio waves are the lowest. Hydrogen gas in space emits radio energy with just a low frequency, which is retrieved as radio waves and is used in remote sensing. They are also employed in radar or sensor systems, where they transmit radio waves and gather the energy that is reflected. Radar devices depict maps of the Earth’s surface and forecast weather patterns because radio radiation is easily transmitted through the atmosphere.

Microwaves: In addition to preparing food, microwaves can transmit information via space. They are also employed in remote sensing, a technique in which microwaves are sent out and reflected on gathering data. Microwaves can be evaluated in centimetres. They are effective for information transmission since the energy can pass radiations through elements like light rain and clouds. Doppler radars can utilise short microwaves to forecast the weather.

Infrared radiation: Thermal energy or heat can be produced through infrared radiation. The energy that is reflected, known as relatively close infrared for its resemblance to visible light energy, can also be used. The most frequent application of infrared radiation is in remote sensing, where infrared sensors gather thermal energy to provide people with weather data.

Visible light: The only region of the electromagnetic spectrum that people can perceive naturally is visible light. This region of the spectrum has a variety of colours, each of which designates a specific wavelength. It is how rainbows are created: light travels through matter, where, depending on its wavelength, it is either absorbed or reflected. As a result, certain hues are reflected in a rainbow more than others.

X-Rays, gamma rays, radiation, ultraviolet, and radiation are all connected to things that happen in space. UV radiation is so well-known due to its harmful impact on the body from the sun, which can result in cancer. X-rays are commonly used to film images of the body organ for medical purposes. Because gamma radiation has a high energy level, people can utilise it in chemotherapy to remove malignancies from the body. Gamma rays, the shortest waves, have a wavelength of about 10–12 m. Human eyes may detect only waves between 390 nm and 780 nm out of this vast range.

Properties of Electromagnetic Radiation 

  1. They are capable of traveling through empty space. Other than electromagnetic waves, all waves must pass through some kind of substance. For example, sound waves will require the passage of a solid, liquid, or gas.
  2. The speed of light is always 2.99792458 x 108 m/s.
  3. The symbol ‘λ’ is used to represent wavelength. It is defined as the distance between two closest points that are in phase with one another. As a result, two adjacent wave crests or troughs are separated by a single complete wavelength.


So what is electromagnetic radiation? It is a form of energy in which photons with wavelike and particle-like characteristics move at the velocity of light. When interacting with any form of matter, these electromagnetic waves transmit energy. The electromagnetic radiation definition states that the energy is inversely correlated with wavelength and inversely proportional to frequency. Consequently, electromagnetic waves with smaller wavelengths carry more energy. Students must comprehend this topic well to understand higher subjects better. 

Frequently Asked Questions 

1. What applications for electromagnetic radiation in food are there?

Ans. The widespread use of electromagnetic radiation in food preparation can kill food-borne bacteria. The electromagnetic spectrum’s microwave or radio wave section has recently been studied for potential applications in food preparation, with positive outcomes for the inactivation of microorganisms. The most widely utilised electromagnetic radiation energy is used in various food processing techniques, including microwave, radiofrequency, irradiation, infrared, visible light, and ultraviolet.

2. How are electromagnetic waves created?

Ans. When a charged particle changes its velocity, like an electron—that is, when it is accelerated or decelerated—electromagnetic radiation is created. The charged particle is responsible for losing the energy of the electromagnetic radiation that is thus created. An antenna’s oscillating current or charge is a typical illustration of this phenomenon.

3. Give a few examples of common everyday electromagnetic radiations.

Ans. Artificially produced electromagnetic radiation permeates all aspects of daily life. For example, microwave ovens cook food, radar waves guide aeroplanes, televisions pick up electromagnetic waves emitted by radio stations, and heaters emit infrared waves to warm spaces. Automated self-focusing webcams that electronically analyse and establish the proper distance to the target to be photographed also emit and receive infrared waves.

Electromagnetic radiations


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