Spectrum
electromagnetic
What is it?
Electromag netic radiation is one of many ways that
energy travels throug h space. The electromagnetic
spectrum is the set of electromagnetic signals, ordered
according to their frequency and wavelength.
An electromagnetic signal is characterized by being
periodic in time, that is, it is repeated in exactly the same
way every given time interval. Electromagnetic waves do
not need a physical medium to propagate (unlike sound,
if there is no air, it does not propagate), this is very
importan t since it allows wireless communications. The
most well-known electromagnetic wave is Light, but they
are present in numerous devices that we use daily:
microwaves, Wi-Fi, Bluetooth, etc.
The electromagnetic spectrum is the set of
electromagnetic radiations that propagate through space
in the form of waves. What identifies each type of
radiation is its frequency, which is the number of cycles
it presents in a given time. It is useful to characterize the
signal in terms of its wavelength, a magnitude, expressed
in meters, that is inversely proportional to frequency and
that measures the distance between two consecutive
peaks of the wave. The energy associated with each of
these wavelengths is expressed in electron volts.
Visible light, i.e. the fraction of the electromagnetic
spectrum that is visible to the human eye, is a tiny part of
the total spectrum. It ranges from the 400 nanometers
that make up violet light – throug h blue, green, yellow
and orange – to red, with approximately 750 nanometers.
Some animals are sensitive to ultraviolet or infrared
light, which provides them with benefits related to
feeding, sexual activity, and defense.
