Skip to main content
Physics LibreTexts

Appendix A: Units

Units Used in Physics (Fundamental units in bold)

Quantity Common Symbol Unit Unit in Terms of Base SI Units
Acceleration $$\vec{a}$$ m/s2 m/s2
Amount of substance n mole mol
Angle $$\theta, \phi$$ radian (rad)  
Angular acceleration $$\vec{\alpha}$$ rad/s2 s-2
Angular frequency $$\omega$$ rad/s s-1
Angular momentum $$\vec{L}$$ kg • m/s2 kg • m/s2
Angular velocity $$\vec{\omega}$$ rad/s s-1
Area A m2 m2
Atomic number Z    
Capacitance C farad (F) A2 • s4/kg • m2
Charge q, Q, e coulomb (C) A • s
Charge density:      
Line $$\lambda$$ C/m A• s/m
Surface $$\sigma$$ C/m2 A• s/m2
Volume $$\rho$$ C/m3 A• s/m3
Conductivity $$\sigma$$ $$\frac{1}{\Omega \cdotp m}$$ A2 • s3/kg • m3
Current I ampere A
Current density $$\vec{J}$$ A/m2 A/m2
Density $$\rho$$ kg/m3 kg/m3
Dielectric constant $$\kappa$$    
Electric dipole moment $$\vec{p}$$ C• m A• s • m
Electric field $$\vec{E}$$ N/C kg • m/A • s3
Electric flux $$\Phi$$ N • m2/C kg • m3/A • s3
Electromotive force $$\varepsilon$$ volt (V) kg • m2/A • s3
Energy E, U, K joule (J) kg • m2/s2
Entropy S J/K kg • m2/s2 • K
Force $$\vec{F}$$ newton (N) kg • m/s2
Frequency f hertz (Hz) s-1
Heat Q joule (J) kg • m2/s2
Inductance L henry (H) kg • m2/A2 • s2
Length: \(\ell\), L meter m
Displacement $$\Delta x, \Delta \vec{r}$$    
Distance d, h    
Position x, y, z, \(\vec{r}\)    
Magnetic dipole moment $$\vec{\mu}$$ N • J/T A • m2
Magnetic field $$\vec{B}$$ tesla (T) = Wb/m2 kg/A • s2
Magnetic flux $$\Phi_{m}$$ weber (Wb) kg • m2/A • s2
Mass m, M kilogram kg
Molar specific heat C J/mol • K kg • m2/s• mol • K
Moment of inertia I kg • m2 kg • m2
Momentum $$\vec{p}$$ kg • m/s kg • m/s
Period T s s
Permeability of free space $$\mu_{0}$$ N/A2 = H/m kg • m/A2 • s2
Permittivity of free space $$\varepsilon_{0}$$ C2/N • m= F/m A2 • s4/kg • m3
Potential V volt (V) = J/C kg • m2/A2 • s3
Power P watt (W) = J/s kg • m2/s3
Pressure p pascal (Pa) = N/m2 kg/m • s3
Resistance R ohm (\(\Omega\)) = V/A kg • m2/A2 • s3
Specific heat c J/kg • K m2/s• K
Speed v m/s m/s
Temperature T kelvin K
Time t second s
Torque $$\vec{\tau}$$ N • m kg • m2/s2
Velocity $$\vec{v}$$ m/s m/s
Volume V m3 m3
Wavelength $$\lambda$$ m m
Work W joule (J) = N • m kg • m2/s2


  • The OpenStax College name, OpenStax College logo, OpenStax College book covers, OpenStax CNX name, and OpenStax CNX logo are not subject to the creative commons license and may not be reproduced without the prior and express written consent of Rice University. For questions regarding this license, please contact Download for free at