Presentation on the telephone Guadalupe Mendoza and Joanna Sandoval. If you have any questions, be ready to pose them in class. An aside on the electromagnetic spectrum. The spectrum is part of the natural world, the radiation emitted by both natural and artificial sources.
Visible light is part of the spectrum, as are x-rays, radio waves, and many other phenomena.
In the United States, the FCC has the responsibility for assigning portions of the spectrum for use, though the spectrum itself is regarded as a natural resource, owned by no one, but administered by the government on our behalf. Click here for an illustration of the spectrum.