# Fundamental and Derived Units

Some Physical Fundamental and Derived Units.

## Fundamental (Primary) Units

Quantity Name of Unit Definition
length meter (m)
mass kilogram (kg)
time second (s)
electric current ampere (A) Coulomb/second
thermodynamic temperature     kelvin (K)
amount of substance mole (mol)
luminous intensity candela (cd)

## Derived Units

Quantity Name of Unit Definition
capacitance farad (F) Coulomb/volt, (amp * second/volt)
charge, quantity of Coulomb (C) (amp * second)
energy (work) Joule (J) Newton-meter, (kg * m2 / sec2)
force Newton (N) Joules/meter, kg * m / sec2
inductance Henry (H) volt * second/Ampere
magnetic flux Weber (Wb) volt * second, (Mead page11)
magnetic flux density Tesla (T) (Webers / meter2); (joules * second) / (Coulomb * meter2);
(Note: 1 tesla = 1.0e4 Gauss = 1Newton/(amp * meter))
potential difference (electromotive force)     volt (V) joules/Coulomb, (kg * m2 / (sec2 * Coulomb)), watts/Ampere
power Watt (W) joules/second, (volts * Ampere)
resistance Ohm volts/Ampere

## Fundamental Constants

Constant Symbol Value
speed of light C 2.99792458e8 m/s, Halliday-Resnick appendix B
charge, elementary e 1.60217738e-19 C, Halliday-Resnick appendix B
electric permittivity constant (in vacuum) epsilon0     8.85418781762E-12 F/m, Halliday-Resnick appendix B
Planck’s constant h 6.6260754e-34 j-s, Halliday-Resnick appendix B
Planck’s constant / (2.0 * pi) hbar 1.055e-34 joules-sec
Complex number i sqrt(-1)
magnetic permeability constant (in vacuum)     mu0 4.0 * pi * 1.0e-7 H/m (Newton/amp2), GriffithsED page216 Eqn:D.1