We explain what the electromagnetic spectrum is, what regions it is divided into, what it is used for and how it was discovered.
What is the electromagnetic spectrum?
The electromagnetic spectrum is the distribution on of energies of electromagnetic radiation. It can be expressed in terms of energy although it is more commonly done in terms of the wavelength and frequencies of the radiation. It extends from radiation with a shorter wavelength (gamma rays) to those with a longer wavelength (radio waves).
It is made up of various subranges or portions, whose limits are not completely defined and tend to overlap. Each band of the spectrum is distinguished from the others in the behavior of its waves during emission, transmission and absorption as well as in its practical applications.
Electromagnetic waves are vibrations of electric and magnetic fields that carry energy. These waves propagate in a vacuum at the speed of light.
When talking about the electromagnetic spectrum of an object, we refer to the different wavelengths that it emits (called emission spectrum) or absorbs (called absorption spectrum), thus generating a distribution of energy in the form of a set of electromagnetic waves.
The characteristics of said distribution depend on the frequency or wavelength of the oscillations as well as its energy. The three quantities are associated with each other: a given wavelength corresponds to a given frequency and energy. Electromagnetic waves can be associated with a particle called a photon.
The electromagnetic spectrum It was discovered following the experiments and contributions of the British James Maxwell who discovered the presence of electromagnetic waves and formalized the equations of his study (known as Maxwell's equations).
See also: Electromagnetism
Regions of the electromagnetic spectrum
The electromagnetic spectrum, in principle, It is practically infinite (for example the longest wavelength would be the size of the universe) and continuous but so far we have been able to learn about some of its regions, known as bands or segments. These are, from smallest to largest:
- Gamma rays With a wavelength less than 10-11 meters (m) and a frequency greater than 1019.
- X-ray With a wavelength less than 10-8 m and a frequency greater than 1016.
- Extreme ultraviolet radiation With a wavelength less than 10-8 m and a frequency greater than 1.5×1015.
- Near ultraviolet radiation With a wavelength less than 380×10-9 m and a frequency greater than 7.89×1014.
- Visible spectrum of light With a wavelength less than 780×10-9 m and a frequency greater than 384×1012.
- Near infrared With a wavelength less than 2.5×10-6 m and a frequency greater than 120×1012.
- Mid infrared With a wavelength less than 50×10-6 m and a frequency greater than 6×1012.
- Far infrared or submillimeter With a wavelength less than 350×10-6 m and a frequency greater than 300×109.
- Microwave radiation With a wavelength less than 10-2 m and a frequency greater than 3×108.
- Ultra high frequency radio waves With a wavelength less than 1 m and a frequency greater than 300×106.
- Very high frequency radio waves With a wavelength less than 100 m, a frequency greater than 30×106Hz.
- Short wave radio With a wavelength less than 180 m and a frequency greater than 1.7×106.
- Medium wave radio With a wavelength less than 650 m and a frequency greater than 650×103Hz.
- Long wave radio With a wavelength less than 104 m and a frequency greater than 30×103.
- Very low frequency radio wave With a wavelength greater than 104 m, a frequency less than 30×103 Hz.
The regions of the electromagnetic spectrum are gamma rays, x-rays, ultraviolet radiation, the visible spectrum, microwaves, and radio frequency.
Uses of the electromagnetic spectrum
The uses of the electromagnetic spectrum can be very diverse. For example:
- Radio frequency waves They are used to transmit information through the air, such as radio broadcasts, television or Wi-Fi Internet.
- The microwaves They are also used to transmit information, such as mobile (cellular) telephone signals or microwave antennas. It is also used by satellites as a mechanism for transmitting information to the ground. And they are used, at the same time, to heat food in microwave ovens.
- Ultraviolet radiation It is emitted by the Sun and absorbed by plants for photosynthesis, as well as by our skin when we tan. It also powers fluorescent tubes and allows the existence of facilities such as solariums.
- Infrared radiation It is what transmits heat from the Sun to our planet, from a fire to the objects around it, or from heating to the interior of our rooms.
- The visible light spectrum. It makes things visible. In addition, it can be used for other visual mechanisms such as cinema, flashlights, etc.
- X-rays They are used in medicine to take visual impressions of the inside of our bodies, such as our bones, while gamma rays, much more violent, are used as a form of radiotherapy or treatment for cancer, since they destroy the DNA of cells. that reproduce out of order.
Importance of the electromagnetic spectrum
In the contemporary world, the electromagnetic spectrum It is a key element for telecommunications and the transmission of information. It is also essential in exploratory techniques (radar/sonar type) of outer space as a way to understand astronomical phenomena distant in time and space.
It has various medical and practical applications which are, furthermore, part of what we take as quality of life today. That is why its manipulation is, without a doubt, one of the great discoveries of humanity.
References
- “Electromagnetic spectrum” on Wikipedia.
- “Light: electromagnetic waves, electromagnetic spectrum and photons” in Khan Academy.
- “The electromagnetic spectrum” at the University of the Basque Country.
- “Electromagnetic and radioelectric spectrum” in Educalab ICT Resources.
- “Electromagnetic spectrum” in The Encyclopaedia Britannica.
