O electromagnetic spectrumis the distribution of electromagnetic waves, visible and not visible, according to the frequency and wavelength characteristic of each radiation. Electromagnetic waves are those that propagate independently of the presence of a material medium and have Maximum speed, referring to the propagation in vacuum, of 300,000 km/s.
O human eye it is only able to discern a small portion of all existing electromagnetic radiation. The range that can be perceived by the human visual system is called visible electromagnetic spectrum. The visible spectrum starts at the frequency that corresponds to red light and ends at the frequency of violet light. The sequence of colors in the visible spectrum is: red, orange, yellow, green, blue, indigo, and violet.
Any radiation that has a frequency lower than that of red light is called infrared. When frequencies are higher than violet light, radiation is classified as ultraviolet.
electromagnetic radiations
→ Radio waves
At radio waves have a minimum frequency of 3,000 GHz and are widely used for data transmission and location through
radars. the brazilian Roberto Landell de Moura was the first person to be able to transmit data through electromagnetic waves, making room for the creation of radio and telephone.→ Microwave
These are radiations that have a frequency between the infrared wave and radio waves. Microwaves are used for heating food in microwave ovens, radars, television broadcasts etc.
The water molecules present in food resonate with the microwaves released by the microwave oven's magnetron. The increased movement of water molecules generates the heating of food.
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→ Infrared
THE infrared radiation it is used in the remote controls of several devices, in the observation of satellites and in heating materials for the automotive and textile industries.
Any object that exchanges heat with the environment presents an infrared wave. The image above was obtained using a camera sensitive to infrared radiation, which highlights in red the regions of the body where the temperature is highest.
→ Ultraviolet
THE ultraviolet radiation is comprised between visible light and theX ray. The ultraviolet radiation emitted by the Sun stimulates the creation of melaninTherefore, when exposed to the sun for a certain time, it is possible to take advantage of the incidence of radiation to generate the effect of tanned skin.
→ X-rays
You X ray are high-frequency electromagnetic waves that have the ability to penetrate low-end systems. density. They are used for imaging diagnosis.
X-rays can pass through human tissue, but are blocked by the greater density of bones. This provides imaging for fracture diagnosis, for example.
→ Gamma rays
You gamma they are very high frequency electromagnetic waves produced by nuclear transitions. Due to their high penetration power, they are used in radiotherapy for cauterization of tumor cells.
By Joab Silas
Graduated in Physics
Would you like to reference this text in a school or academic work? Look:
JUNIOR, Joab Silas da Silva. "What is the electromagnetic spectrum?"; Brazil School. Available in: https://brasilescola.uol.com.br/o-que-e/fisica/o-que-e-espectro-eletromagnetico.htm. Accessed on June 27, 2021.
