Mega
From Wikipedia, the free encyclopedia
- For other meanings, see Mega (disambiguation)
mega- (symbol M) is an SI prefix in the SI system of units denoting a factor of 106, 1,000,000 (one million).
For example, 1 MW (megawatt) = 1,000,000 watts = 1,000 kilowatts.
Confirmed in 1960, it comes from the Greek μέγας, meaning great.[citation needed]
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[edit] Other common examples of usage
- one megaton [of TNT] (a unit often used in measuring the explosive power of nuclear weapons) is 1,000,000 tTNT.
- megahertz — frequency of electromagnetic radiation for radio and television broadcasting, GSM, etc. 1 MHz = 1,000,000 Hz
[edit] Square and cubic forms
As the SI-prefixes take precedence over exponents,
- 1 Mm² means one square megametre or the size of a square of 1,000,000 m × 1,000,000 m or 1012 m² (and not 1,000,000 × a square metre or 106 m²)
- 1 Mm³ means one cubic megametre or the size of a cube of 1,000,000 m × 1,000,000 m × 1,000,000 m or 1018 m² (and not 1,000,000 × a cubic metre or 109 m²)
[edit] Computing
In computing, mega- can sometimes denote 1,048,576 (220) of information units (example: a megabyte, a megaword), but can denote 1,000,000 (106) of other quantities, for example, transfer rates: 1 megabit/s = 1,000,000 bit/s.
The prefix mebi- has been suggested as a prefix for 220 to avoid ambiguity, but is yet to be widely used.
| 1000n | 10n | Prefix | Symbol | Short scale | Long scale | Decimal equivalent in SI writing style |
|---|---|---|---|---|---|---|
| 10008 | 1024 | yotta | Y | Septillion | Quadrillion | 1 000 000 000 000 000 000 000 000 |
| 10007 | 1021 | zetta | Z | Sextillion | Trilliard (thousand trillion) | 1 000 000 000 000 000 000 000 |
| 10006 | 1018 | exa | E | Quintillion | Trillion | 1 000 000 000 000 000 000 |
| 10005 | 1015 | peta | P | Quadrillion | Billiard (thousand billion) | 1 000 000 000 000 000 |
| 10004 | 1012 | tera | T | Trillion | Billion | 1 000 000 000 000 |
| 10003 | 109 | giga | G | Billion | Milliard (thousand million) | 1 000 000 000 |
| 10002 | 106 | mega | M | Million | 1 000 000 | |
| 10001 | 103 | kilo | k | Thousand | 1 000 | |
| 10002/3 | 102 | hecto | h | Hundred | 100 | |
| 10001/3 | 101 | deca, deka | da | Ten | 10 | |
| 10000 | 100 | (none) | (none) | One | 1 | |
| 1000−1/3 | 10−1 | deci | d | Tenth | 0.1 | |
| 1000−2/3 | 10−2 | centi | c | Hundredth | 0.01 | |
| 1000−1 | 10−3 | milli | m | Thousandth | 0.001 | |
| 1000−2 | 10−6 | micro | µ (u) | Millionth | 0.000 001 | |
| 1000−3 | 10−9 | nano | n | Billionth | Milliardth | 0.000 000 001 |
| 1000−4 | 10−12 | pico | p | Trillionth | Billionth | 0.000 000 000 001 |
| 1000−5 | 10−15 | femto | f | Quadrillionth | Billiardth | 0.000 000 000 000 001 |
| 1000−6 | 10−18 | atto | a | Quintillionth | Trillionth | 0.000 000 000 000 000 001 |
| 1000−7 | 10−21 | zepto | z | Sextillionth | Trilliardth | 0.000 000 000 000 000 000 001 |
| 1000−8 | 10−24 | yocto | y | Septillionth | Quadrillionth | 0.000 000 000 000 000 000 000 001 |
