µm and microns

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bluesfan
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µm and microns

Postby bluesfan » Mon 23 Jul 2007 3:44 pm

please forgive my ignorance... is the micrometre or "µm" the same as microns? (i.e. does a cornea with 560 µm the same as a cornea of 560 microns thickness?)

Tried already to "google" this but cou;dn't get definitive answer. Thanks for your help!

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Marc Pritchard
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Postby Marc Pritchard » Mon 23 Jul 2007 5:04 pm

A micrometre (American spelling: micrometer; symbol µm) is an SI unit of length equal to one millionth of a metre, or equivalently, one thousandth of a millimetre. It is also commonly known as a micron. It can be written in scientific notation as 1×10−6 m, meaning 1 / 1,000,000 m.

The symbol µm's character µ (Unicode character U+00B5; HTML µ) is the "micro sign", which should look identical to the Greek letter mu (μ) (the two may or may not look the same, depending on the font). The symbol "um" is sometimes used, when the µ and μ are not available, for example in ASCII, or when using a typewriter.

The micrometre is a common unit of measurement for wavelengths of infrared radiation. Some people (especially in astronomy and the semiconductor industry) use the old name micron and/or the solitary symbol µ (both of which were official[citation needed] between 1879 and 1967) to denote a micrometre. This practice persists in the face of official discouragement, perhaps to help disambiguate between the unit of measurement and the micrometer, a measuring device.




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Postby GarethB » Mon 23 Jul 2007 5:46 pm

I use these units daily and they are the same, micron is an abreviaion of micrometer and µm is more of an abreviation/symbol.
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Postby bluesfan » Mon 23 Jul 2007 9:57 pm

Thanks MArc and Gareth for helping out!!

Thanks for the hint on ask.co.uk I will check it out !! Indeed Wikipedia is a very handy website and always interesting to look up although just a word of caution I have come across some very questionable "facts" on the wikipedia from time to time! so its alays good to procced with care over there!


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