TheĀ micrometreĀ (International spellingĀ as used by theĀ International Bureau of Weights and Measures;[1]Ā SIĀ symbol:Ā Ī¼m) orĀ micrometerĀ (American spelling), alsocommonly knownĀ as aĀ micron, is anĀ SI derived unitĀ ofĀ lengthĀ equaling 1Ć10ā6Ā of ametreĀ (SI standard prefix "micro-" = 10ā6); that is, one millionth of a metre (or one thousandth of a millimetre, 0.001Ā mm, or about 0.000039Ā inch).[1]Ā The symbol Ī¼m is sometimes rendered as um if the symbolĀ Ī¼Ā cannot be used, or if the writer is not aware of the distinction.[citation needed]
The micrometre is a common unit ofĀ measurementĀ forĀ wavelengthsĀ ofĀ infrared radiationĀ as well as sizes of biologicalĀ cellsĀ andĀ bacteriaĀ and is also commonly used in plastics manufacturing.[1]Ā Micrometres are the standard for grading wool by the diameter of the fibres; wool finer than 25Ā Ī¼m can be used for garments, while coarser grades are used for outerwear, rugs, and carpets.[2]Ā The width of a single human hair ranges from approximately 10 to 200Ā Ī¼m. The first and longest human chromosome is 10Ī¼m in length.
ContentsĀ Ā [hide]Ā 1Examples2SI standardization3Symbol4See also5Notes and references