Concept Map

Key Terms

amplitude

the height, or magnitude, of an electromagnetic wave

electromagnetic spectrum

the full range of wavelengths or frequencies of electromagnetic radiation

electromagnetic waves

radiation in the form of waves of electric and magnetic energy

frequency

the number of complete wave cycles (up-down-up) passing a given point within one second (cycles/second)

gamma ray

extremely high frequency electromagnetic radiation emitted by the nucleus of an atom, either from natural nuclear decay or induced nuclear processes in nuclear reactors and weapons.

hertz

an SI unit denoting the frequency of an electromagnetic wave, in cycles per second

microwaves

electromagnetic waves with wavelengths in the range from 1 mm to 1 m; they can be produced by currents in macroscopic circuits and devices

oscillate

to fluctuate back and forth in a steady beat

radar

a common application of microwaves. Radar can determine the distance to objects as diverse as clouds and aircraft, as well as determine the speed of a car or the intensity of a rainstorm

radio waves

electromagnetic waves with wavelengths in the range from 1 mm to 100 km; they are produced by currents in wires and circuits and by astronomical phenomena

speed of light

in a vacuum, such as space, the speed of light is a constant 3 x 10⁸ m/s

transverse wave

a wave, such as an electromagnetic wave, which oscillates perpendicular to the axis along the line of travel

visible light

the narrow segment of the electromagnetic spectrum to which the normal human eye responds

wavelength

the distance from one peak to the next in a wave

X-ray

invisible, penetrating form of very high frequency electromagnetic radiation, overlapping both the ultraviolet range and the gamma-ray range

More terms can be found in the textbook, chapter 24