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A
little more about Electromagnetic Waves
There are many kinds of electromagnetic waves. They
all have the same velocity (which is the speed of light and is
300,000,000 m/s) and they all consist of changing electric and magnetic
fields. A changing electric field produces a changing magnetic
field and vice versa, which causes the wave to propagate.
Electromagnetic waves make up a spectrum, or a continuous distribution
of frequencies. Since the energy of the wave depends on its
frequency, each type of electromagnetic wave has a different
energy. They all also have different wavelengths.
The velocity is the same, so waves with high frequency (energy) have a
smaller wavelength than waves with a lower frequency. Microwaves are
classified as radio waves, and are on the low energy end of the
spectrum. The frequency of the microwaves produced by a microwave
oven is 2450 MHz, as set by the FCC. This means they have a wavelenth
of 300,000,000 m/s divided by 2,450,000,000 Hz = .122 meter, or about
12 centimeters.
Copyright © National Aeronautics and Space Administration,
Langley
Research Center, http://www.nasa.gov/centers/langley/images/content/114284main_EM_Spectrum500.jpg
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