Today, if we ask someone about electromagnetic radiation, we will certainly hear that it is dangerous or that it poses a health risk. Some may even mention radioactive elements, 5G networks or X-rays. However, this is not entirely true. Every day we deal with electromagnetic radiation. This happens even more often than you think. Let me explain.
Electromagnetic radiation is electromagnetic waves which penetrate space and carry some amount of energy. In practice it means radio waves, infrared, visible light, ultraviolet, X-rays and gamma rays. All of it considered to be electromagnetic radiation.
Picture 1. Electromagnetic spectrum | Photo Credit: NASA
That’s the lowest part of electromagnetic spectrum in frequency range between >0Hz and 300GHz (wavelength from ~100 000km to 1mm) and the most used . Particularly it’s utilized for the purpose of transferring information (from point A to point B), in television and radio broadcasting, radars, navigation satellites, radioastronomy, microelectronics, cellphones (3G, 4G, 5G), cordless phones, remote control devices, wireless routers, microwave links, bluetooth, baby monitors, smart meters, surgery, physiotherapy, microwave ovens and many other devices.
Microwaves are electromagnetic waves which lay in frequency range between 300MHz and 300GHz (wavelength from 1m to 1mm). It’s not really clear if microwaves should be considered as radio waves. Some sources classify it as separate group, other as a subset of radio waves (so did I).
From all types of electromagnetic radiation radio waves carry the smallest amount of energy. The quota is that low it’s not enough to split electron from atom or break chemical bonds (causing DNA damage). Therefore radio waves are classified as nonionizing radiation. All energy transfered by them manifests itself as heat (or kinetic energy of particles). Other way saying radio waves change subject’s temperature. Per instance, this is the way we cook things in microwave oven. However radio waves (microwaves) cannot be considered as safe electromagnetic radiation. So absorbed by human body they can harm and have an affect on health (especially if we talk about long exposure). Studies have shown the effects on the central nervous system, learning and memory abilities and mechanisms of underlying brain dysfunction, oxidative stress and many others .
Infrared electromagnetic waves positioned in frequency range between 300GHz and 430THz (wavelength from 1mm to 700nm). More energetic than radio waves, infrared used in heat sensors, thermal imaging, night vision, infrared astronomy, wired and wireless devices, remote controls, fiber optic cables, electric heater, cordless hair dryers, toasters etc. Heat and thermal radiation is the main source of infrared. Basically anything that has temperature and isn’t hot enough to emit visible light, will end up emitting infrared radiation.
Microwaves and infrared waves are next to each other on the spectrum of electromagnetic waves, but they have completely different properties. The first ones carry less energy and have a lower wavelength than the second one. As a rule, usually infrared is absorbed by the surfaces of objects, and microwaves penetrate them.
The visible light has the frequency range between 430THz and 750THz (wavelength from 700nm to 400nm). This is the only type of radiation visible to the human eye. The sun is the main source of visible light. Visible light is used to observe the world, photosynthesis (by living organisms), astronomy, lasers, monitors, television and others.
Ultraviolet light is next on electromagnetic spectrum having frequency range between 750THz and 30PHz (wavelength from 400nm to 10nm). The amount of energy transmitted by ultraviolet waves is sufficient to separate the electron from the atom, therefore we classify it as ionizing radiation (i.e. dangerous for living organisms). Ultraviolet light is used in bug zappers, inks for printers, for disinfection, in optical sensors, in medical, spectroscopy, photo-ionization and others.
While high-energy ultraviolet light is absorbed by the Earth’s atmosphere, ultraviolet waves with low energy reach the surface. They are the reason for sunburn (not visible light). It is worth remembering that a long exposure under ultraviolet waves is very harmful to the human body.
X-rays lay in frequency range between 30PHz and 30EHz (wavelength from 10nm to 10pm). It carries more energy than ultraviolet radiation, which is why it is much more dangerous. It has been classified as ionizing radiation, because X-rays can easily separate electrons from atoms and break chemical bonds. Regardless, we have found application even for this type of radiation. It’s used in medicine, airport security, astronomy, art analysis.
Everything above frequency 30EHz (wavelength bellow 10pm) is called gamma rays. This type of ionizing radiation carries even more energy than X-ray radiation. Gamma rays are used in medicine and astronomy.
Picture 2. Warning microwave radiation | Photo Credit: Pixabay / Clker-Free-Vector-Images
- Radiowaves https://www.nasa.gov/directorates/heo/scan/communications/outreach/funfacts/txt_radio_spectrum.html
- Infrared https://www.nasa.gov/audience/forstudents/5-8/features/F_Infrared_Light_5-8.html
- Spectrum http://www.davidterr.com/science-articles/electromagnetic_spectrum.html