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This article defines and compares frequency measurements expressed in Hertz, Kilohertz kHz, Megahertz MHz, Gigahertz GHz, and Terahertz THz .
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Relation of wavelength to frequency & speed: notice that the shorter the wavelength the higher the frequency. That's why in our table above as the wavelengths get smaller (notice those negative exponents?) the electromagnetic frequency numbers get larger. More technically, wavelength is inversely proportional to wave frequency.
Do not confuse wavelength and frequency of an electromagnetic wave with its speed. All electromagnetic waves move at or close to the speed of light (and do move at the speed of light if measured in a vacuum). The speed of an electromagnetic wave, expressed in meters per second is equal to wavelength (in meters) x frequency (in oscillations per second or Hertz, abbreviated as Hz).
Our table (below) provides definitions of various frequencies or oscillation rates expressed in kilohertz, megahertz, gigahertz, or terahertz.
Separately at Table of EMR Frequencies we provide a separate listing of the frequency in Hertz of various sources of electromagnetic radiation, ranging from ULF - ultra low frequency sources - through UHF - ultra high frequency electromagnetic radiation sources. Because the possible effects of electromagnetic fields on humans, other animals, and even materials varies significantly by frequency (and wavelength, distance, and other factors), readers should also see EMF RF FIELD & FREQUENCY DEFINITIONS.
Also see Definitions of Gauss vs Milligauss for details about gauss and milligauss and definitions of these terms. Also see Electric Power Lines, Electromagnetic Fields, Cancer Risk, & "Enviro-Scare" - The Normal Curve Cycle of Public Fear of Environmental Issues which discusses the impact of EMF and other environmental concerns on property values. And see EMF ELECTROMAGNETIC FIELDS & HUMAN EXPOSURE which discusses EMF exposure in the workplace.
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Frequently Asked Questions (FAQs) about the definitions of Hertz & various frequency measurements
Question: how many zeros in a PetaHertz?
I read in [the article above]
“One petahertz = ten followed by 15 zeros”
I Believe it should be :
One petahertz = one followed by 15 zeros
The same mistake is repeated for the definitions of : Exahertz Zetahertz Yotahertz. - Y. [Annon]
Thank you for the question on clarifying how to write the value of various high-frequency measurements such as Petahertz, Exahertz, etc.
The correct formula for one PHz is 1 x 10 to the 15th power
10 to the 1th is 10
10 to the 2d power is 10 x 10 = 100 (1 followed by two zeroes) making you correct
or 1 followed by fifteen zeroes - you are quite correct and we have amended our article text to be more accurate.
Thank you. Daniel Friedman
Questions & answers or comments about various hertz definitions. .
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