Units, Prefixes

SI-Units

Quantity Symbol Unit
Length l [m]
Mass m [kg]
Time t [s]
Temperature T [K]
Current I [A]
Luminous intensity Iv [Cd]
Amount of substance n [mol]

Which two are exceptional?

Weight: Has a prefix before it

Current: Quotient of two quantities

Prefixes

× 10 deca × 10-1 deci
× 100 hecto × 10-2 centi
× 1000 kilo × 10-3 milli
× 106 mega × 10-6 micro
× 109 giga × 10-9 nano
× 1012 tera × 10-12 pico
× 1015 peta × 10-15 femto
× 1018 exa × 10-18 atto

To represent large or small data:

0.0000000046 s = 4.6 ns

7800000000 Watt = 7.8 GW