Mega is a metric prefix in of units denoting a factor of one million (106 or ). It has the unit symbol M. It was confirmed for use in the International System of Units (SI) in 1960. Mega comes from .
Common examples of usage
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Megapixel: 1 million in a digital camera
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One megatonne of TNT equivalent amounts to approx. 4 and is the approximate energy released on igniting one million tonnes of TNT. The unit is often used in measuring the explosive power of .
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Megahertz: frequency of electromagnetic radiation for radio and television broadcasting, GSM, etc. 1 MHz = 1,000,000 Hertz.
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Megabyte: unit of information equal to one million bytes (SI standard).
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Megawatt: equal to one million watts of power. It is commonly used to measure the output of , as well as the power consumption of electric locomotives, , and other entities that heavily consume electricity.
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Megadeath: (or megacorpse) is one million human deaths, usually used in reference to projected number of deaths from a nuclear explosion. The term was used by scientists and thinkers who strategized likely outcomes of all-out nuclear warfare.
Exponentiation
When units occur in
exponentiation, such as in square and cubic forms, any multiples-prefix is considered part of the unit, and thus included in the exponentiation.
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1 Mm2 means one square megametre or the size of a square of by or , and not (106 m2).
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1 Mm3 means one cubic megametre or the size of a cube of by by or 1018 m3, and not (106 m3)
Computing
In some fields of
computing,
mega may sometimes denote (2
20) information units, for example, a megabyte, a megaword, but denotes (10
6) units of other quantities, for example, transfer rates: = .
In the case of 3½-inch floppy disks, sizes were given in megabytes of 1000KB or bytes.
The prefix
mebi- has been suggested as a prefix for 2
20 to avoid ambiguity.
See also
External links
