# Appendix B

# Units in Physics

## B.1. Multiples and submultiples of units

The multiples of units and their submultiples by powers of 10 are designated follows in Table B.1.

**Table B.1.** *Multiples and submultiples*

## B.2. Fundamental and derived SI units

The units of all physical quantities are defined in terms of six *fundamental* (or *basic*) *units*, which are defined by convention: *length*, *time*, *mass*, *current intensity*, *temperature* and *luminous intensity*. The units of the other physical quantities (the so-called *derived units*) are defined with reference to the fundamental units based on the dimensional homogeneity of laws of physics. The International System of Units (SI) uses *meters* (m), seconds (s), *kilograms* (kg), *ampere* (A), *kelvin* (K) and *candela* (cd) as fundamental units. Some branches of science and engineering continue to use the CGS system (based on the *centimeter*, *gram* and *second*) for mechanical quantities. As the whole circumference is divided into 2π *radians*, the unit of angles is the radian. We also use the *degree* (°), *minute* (′) and *second* (″), and sometimes *revolution* (2π radians).

## B.3. Mechanical units

**Table B.2.** *Mechanical units*

## B.4. Electromagnetic units

**Table B3.** *Electromagnetic ...*