Metric prefixes are a way to represent different powers of ten in engineering notation. The table below shows some common metric prefixes along with their symbols and corresponding powers of ten:
These prefixes are used with numbers that have a unit of measure, like volts, amperes, and ohms, and they come before the unit symbol. For instance, 0.025 amperes can be expressed as 25 mA, read as 25 milliamps.
Basic rules for metric unit conversions include:
- When going from a larger unit to a smaller unit, move the decimal point to the right.
- When going from a smaller unit to a larger unit, move the decimal point to the left.
- Determine the number of places to move the decimal point by finding the difference in the powers of ten of the units being converted.
For example, converting 0.15 milliamperes (0.15 mA) to microamperes involves moving the decimal point three places to the right:
0.15 mA = 0.15 * 10^-3 A = 150 * 10^-6 A = 150 µA
Similarly, converting 4500 microvolts to millivolts means moving the decimal point three places to the left:
4500 µV = 4500 * 10^-6 V = 4.5 * 10^-3 V = 4.5 mV
These rules apply to various conversions, making it easy to express quantities in different units.