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What Is Electromagnetic Radiation? An Overview of Electromagnetic Spectrum

Admin December 29 2020 Share this:

Electromagnetic radiation (EMR) is basically a collective term and a form of energy. It includes a range of electromagnetic radiant energies such as radio waves, infrared, X-rays, gamma rays, ultraviolet (UV) rays, and microwaves, etc. The electromagnetic waves that carry energies and travel through space at the speed of light create a non-quantum electromagnetic field (EMF) which, in physics, are “synchronized oscillations of electric and magnetic fields”. 

The visible light in our homes from natural as well as man-made sources, and the radio waves coming out of the radio station are also electromagnetic radiation. 

Electromagnetism by Maxwell

Till 1873, both electricity and magnetism were considered separate entities. However, James Clerk Maxwell, a Scottish physicist, put forth a unified theory of electromagnetism in 1873. This theory explains how electrically charged particles have mutual interaction in magnetic fields.

Electromagnetic Waves and Electromagnetic Field (EMF)

In an atom, the atomic particles are accelerated due to the electric field and moved, resulting in the electric and magnetic fields both perpendicular to each other. This oscillating electromagnetic field travels in the form of light energy which is also called a photon. In a vacuum, this photon travels at the speed of light. When both the electric and magnetic fields couple with each other, it results in an electromagnetic wave having certain characteristics such as frequency and wavelength. 

The number of waves in a given period of time is called frequency and measured in hertz (Hz) that is how many wave cycles formed per second. Whereas, the wavelength refers to the distance between the two consecutive peaks of that particular wave. Hence, the electromagnetic waves with shorter wavelengths have a higher frequency and vice versa.  

Electromagnetic Spectrum

When we put all types of electromagnetic radiation in one place according to their frequencies and wavelengths, it forms an electromagnetic spectrum and helps us in a comparative study.


EM Spectrum

(Electromagnetic Spectrum Diagram)

The electromagnetic spectrum (EM Spectrum) consists of a range of frequencies and wavelengths of electromagnetic radiation. We divide the EM spectrum into seven regions according to the pattern of increasing frequencies and decreasing wavelengths. From left to right, these seven electromagnetic radiant energies can be put in the sequence as, Radio waves, microwaves, infrared, visible light, ultraviolet rays, X-rays and the last on the right side is gamma rays. 

The radio waves on the extreme left of the spectrum have lower energy and expressed as frequency, the next regions – microwaves, infrared, visible light, and ultraviolet rays are expressed as wavelength, and the regions on the extreme right on the spectrum – the X-rays and gamma rays have higher energy radiation and hence expressed as energy per photon.

Radiofrequency Waves: Low-frequency Non-ionizing Electromagnetic Radiation

The radio waves or radiofrequency waves (RF Waves) are on the lowest range of the electromagnetic spectrum. The RF Waves have up to about 30 GHz frequencies and the wavelengths are measured about 0.4 Inches (greater than 10 millimeters). All wireless communication devices including IoT devices and equipment such as mobile phones, laptops, smart TVs, network boosters, high-tension power lines, mobile phone towers, etc. use radio waves. The electromagnetic field (EMF) of these radiofrequency waves carry low-frequency electromagnetic radiation (EMR) which is non-ionizing radiation. 

While ionizing radiation such as UV, and X-rays radiation cause serious health issues, exposure to low-frequency non-ionizing radiation is also observed to be harmful to health. As given on the WHO website, “Low-frequency electric fields influence the human body just as they influence any other material made up of charged particles. And, Low-frequency magnetic fields induce circulating currents within the human body. The strength of these currents depends on the intensity of the outside magnetic field. If sufficiently large, these currents could cause stimulation of nerves and muscles or affect other biological processes.”

In May 2011, the International Agency for Research on Cancer (IARC), a WHO agency, classified radiofrequency electromagnetic field (RF-EMF) as “possibly carcinogenic” to humans. The RF-EMF is produced by mobile phones and other wireless communication devices. The electromagnetic radiation (EMR) from all kinds of wireless communication devices causes cancer including brain tumors, birth defects, fertility issues, higher levels of stress, fatigue, and irritation, to name a few.


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