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

7c2d2dd433a429dec7d9df2eeb469eaf.png Eqn:D.1

See Also