A unit of length, used especially in expressing the length of light waves, isthe nanometer, abbreviated as nm and equal to 10−9 meter.
Because in the United States measurements are occasionally reported in units
of the English system, it is important to be aware of some metric to English
system equivalents. Some common conversion factors are shown in the following
table.
TIP
For your information only; metric is used on the test.The metric system standards were chosen as natural standards. The meter
was once described as 1/10,000,000 of the distance between the equator and the
North Pole but now is defined as the length of the path traveled by light in a
vacuum during a time interval of 1/2.99792458 × 10^8 second.
There are some interesting relationships between volume and mass units in
the metric system. Because water is most dense at 4°C, the gram was intended to
be 1 cubic centimeter of water at this temperature. This means, then, that:
1,000 cm^3 = 1 L of water @ 4°C