What we know as "light" is but a narrow region of the electromagnetic spectrum.
Figure 5.6 The electromagnetic spectrum from 0 to 15 m.
They work in or near the visual part of the electromagnetic spectrum.
Yet we know well that our eyes can see only a small part of the electromagnetic spectrum.
The ship looked across the entire electromagnetic spectrum and saw nothing but the natural background.
Yet the light we can see represents only a very small portion of the electromagnetic spectrum.
The problem is we have to look at the electromagnetic spectrum for wireless communications.
In fact energy covering much of the electromagnetic spectrum comes from the sun.
We only see light in a tiny band of the electromagnetic spectrum.
The whole range of radiation is called the electromagnetic spectrum.