EM 1110-2-2907
1 October 2003
light, microwaves, and radio waves. All of these waves move and behave similarly; they
differ only in radiation intensity.
f. Measurement of Electromagnetic Wave Radiation.
(1) Wavelength. Electromagnetic waves are measured from wave crest to wave
crest or conversely from trough to trough. This distance is known as wavelength (λ or
"lambda"), and is expressed in units of micrometers (m) or nanometers (nm) (Figures 2-
4 and 2-5).
Crest
λ
λ
Trough
Figure 2-4. Wave morphology--wave-
length (λ) is measured from crest-to-crest
or trough-to-trough.
Figure 2-5. Long wavelengths maintain a low frequency and lower energy state relative to
the short wavelengths.
(2) Frequency. The rate at which a wave passes a fixed point is known as the wave
frequency and is denoted as ν ("nu"). The units of measurement for frequency are given
as Hertz (Hz), the number of wave cycles per second (Figures 2-5 and 2-6).
2-5
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