Graphics Reference
In-Depth Information
The electromagnetic spectrum
10
2
6
nm
10
2
5
nm
10
2
4
nm
10
2
3
nm
Gamma rays
10
2
2
nm
10
2
1
nm
1 nm
10 nm
10 nm
100 nm
1
å
X-rays
Violet
Indigo
Blue
Green
Yellow
Orange
Red
Ultraviolet
Visible light
Near infrared
10
3
nm
10
1
m
m
100
m
Far infrared
1000
m
1 mm
10 mm
10 cm
100 cm
1 cm
Microwave
1 m
10 m
100 m
1000 m
1 km
Radio
10 km
100 km
1 Mm
10 Mm
100 Mm
nm = nanometer,
Å
= angstrom,
m = micrometer, mm = millimeter,
cm = centimeter, m = meter, km = kilometer, Mm = Megemeter
Figure 26.5: The electromagnetic spectrum includes many different phenomena; visible
light occupies only a small portion of the spectrum.
when we speak of “light.”) Other kinds include X-rays, microwaves, etc. (see Fig-
ure 26.5). The wave nature of light is best used when trying to understand how
light propagates; in fact, a good rule of thumb is that “[e]verything propagates
like a wave and exchanges energy like a particle” [TM07]. To understand the
propagation of light, we must discuss kinds of waves.
Large and regular waves on the surface of the ocean are
linear waves
—each
peak and trough consists of a long line that moves in a direction perpendicular to
the axis of the line (see Figure 26.6). The
wavelength
is the perpendicular distance
between adjacent peaks (or adjacent troughs). The
wave velocity
is the velocity
with which the peak moves. This is not the velocity of any individual particle
of water, which is easy to see by watching, for instance, a log floating on the
