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Electromagnetism 101 | National Geographic


[Music]
electromagnetism or the electromagnetic
force is one of the four fundamental
forces of nature it generates light and
energy and holds atoms matter and the
world as we know it together
[Music]
electromagnetism is a branch of physics
that studies the interactions between
electric and magnetic fields all matter
has an electric charge which can be
positive negative or zero opposite
charges attract while like charges repel
these electric forces bring and hold
atoms together and when atoms gain a
positive or negative charge through the
transfer of electrons a measurable
electric field will form if those
electrically charged particles start to
move the field will become a flowing
electric current and form a magnetic
field around it under the right
circumstances interacting electric and
magnetic fields can continuously produce
and sustain one another this generates
an electromagnetic field that transmits
waves of electromagnetic energy or
radiation into space the intensity of
this radiation is determined by its
frequency these frequencies make up
what’s known as the electromagnetic
spectrum near the middle of the spectrum
is visible light such as light emitted
by stars fireflies and computer screens
on either side are invisible
electromagnetic waves on one end are
long low frequency radio waves that
broadcast television and radio signals
microwaves that carry telephone signals
and cook food and infrared waves emitted
by fires
on the other are short high-frequency
wavelengths ultraviolet X and gamma
radiation
unlike low-frequency waves these waves
can pass through the human body making
them useful for medical applications
while electromagnetism has daily
applications it’s also the engine that
drives the planet as a whole
thousands of miles below the earth’s
surface a layer of liquid metals churn
and flow this generates electric
currents that then produce magnetic
fields that altogether encompassed the
entire planet called a geo dynamo this
process causes Earth’s poles to attain
positive and negative charges turning
the planet into a giant electromagnet
this phenomenon also creates a
protective layer around the planet it
shields us from the most harmful
radiation in space leaving us to enjoy a
world held together by the strange and fundamental force of electromagnetism
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