IntroductionX ray, invisible, highly penetrating electromagnetic
radiation of much shorter wavelength (higher frequency) than
visible light. The wavelength range for X rays is from about 10
- 8 m to about 10 - 11 m, or from less than a billionth of an
inch to less than a trillionth of an inch; the corresponding
frequency range is from about 3 × 1016 Hz to about 3 × 1019 Hz
(1 Hz = 1 cps). Sections in this article: The Columbia
Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia
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articles on: Physics