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Unformatted text preview: around us. Artificial sources
such as radio and television, microwave radar detection systems, telephone signals, light bulbs, and medical
equipment, are also contributors. We have learned a great deal about nature and the structure of the atom by
monitoring radiation with microscopes, telescopes and other scientific equipment. The continuum of this radiation
is known as the electromagnetic spectrum. It includes x- rays and gamma rays; ultra- violet, visible, and infrared
light; microwaves and radiowaves. Human vision is limited to the very narrow band of visible light.
Electromagnetic radiation can be described as a wave characterized by two interdependent variables:
Fre que ncy, ν (nu), is the number of waves passing a certain point per second. Frequency is measured in
Hertz (Hz). 1 Hz = 1 cycle/sec.
Wave le ngth, λ (lambda), is the distance between a point on one wave and the corresponding point on
the next wave. Wavelength is measured in units of length, which are convenient for the type of radiation
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This document was uploaded on 01/22/2014.
- Spring '14