SI prefixes

This appendix lists the SI prefixes, base units for physical quantities in the SI system, and some useful SI-English conversions. 

Use Table A-1 as a handy reference for the abbreviations and meanings of various SI prefixes. 

The base unit for length in the SI system is the meter. The exact definition of meter has changed over the years, but it s now defined as the distance that li t travels in a vacuum in J499.792.4s8 of a second. Here are some SI units of lei th  

Some common English to SI system length conversions are 

The International System of Units (SI) prefixes are presented in Table 1.2. 

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NEW The Fact Sheet at the back of the book provides students with a single source for most of the information they need to solve problems. The fact sheet includes a list of key equations for each chapter the periodic table and tables of the elements, SI prefixes, fundamental constants, and relations between units. 

The unit of time is the second in the fundamental list of constants but it is convenient to use years when referring to the age of the Universe, Solar System or the Earth. I have chosen to use the SI prefixes in front of the symbol yr so that 109 years is 1 Gyr the age of the Universe is 15 billion years or 15 Gyr, etc., and whenever this refers to a period of time in the past then 4.5 Gyr ago will be used explicitly. 

Practice using the SI prefixes and units and conversions below ... 

Note that the curie is a much larger unit than the becquerel and SI prefixes are commonly used with both units to signify ordinary working levels of... 

The CIPM has approved twenty prefixes for SI units (see Table 3) and permits the use of any SI prefix with an SI unit, with one exception. The SI unit for mass, the kilogram, already has a prefix in its name and can have no other SI prefix. To use prefixes with a unit for mass, the rule is to remove the kilo prefix and add the new prefix to gram (unit symbol g), as in milligram and its abbreviation mg. 

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