EE47008 Notation and symbols, in SI1 units Quantity Area (A) Capacitance (C) Description length × length charge/potential Charge density either, linear charge density ρl (charge/length) surface charge density ρs (charge/area) volume charge density ρv (charge/volume) current × time electron charge 1/resistance conductance/length charge/time current/area energy out/energy in p = qd force/charge or potential/length electric flux = ∫surface D•ds =Q D is electric flux/area mass × acceleration cycles/second magnetic flux/current ∫loop H•dl = I Charge(Q) fundamental (q) Conductance Conductivity (σ) Current (I) Current density (J) Efficiency (η) Electric dipole (p) Electric field (ξ ) Electric flux density (D) Force (F) Frequency (f) Inductance (L) Length (l, d) Magnetic field intensity (H) Magnetic flux (Φ) Magnetic field (B) Mass (m) Permeability (µo) Permittivity (εo), dielectric constant Polarization (P) Potential Power Φ = ∫s B•ds magnetic flux density (Φ/area) for vacuum for vacuum or air at atmospheric pressure electric dipole/volume voltage energy/time Units square meters (m2) Coulomb/volt (C/V), Farad (F) C/m C/m2 C/m3 Coulomb (C) 1.602 x 10‐19 C 1/Ohm, Ω‐1 Ω‐1m‐1 A A/m2 dimensionless, % C m V/m C/m2 Newton (N) Hertz, (Hz or s‐1) Henry (H) or Wb/A meter (m) A/m Weber (Wb) Tesla (T) Weber/m2 (Wb/m2) kilogram (kg) Henry/meter (H/m) F/m C/m2 V Watt (W) Bold face indicates vector quantities 1 International System of Units (SI), The NIST Reference on Constants, Units, and Uncertainty, http://physics.nist.gov/cuu/Units/, Aug. 2, 2008. Quantity Power density Relative permittivity (εr) Resistance (R) Resistivity (ρ) Seebeck coefficient (Q) Description power/area material permittivity/ε o voltage/current resistance × length electric field/temperature gradient Strain (s) relative change in length Δl/l Stress (σ) force/area Temperature (T) Time (t) Thermal conductivity (κ) Watts/Kelvin/meter Thermoelectric Q2/κσ figure‐of‐merit (Z) Velocity (v) distance/time Wavelength (λ) propagation velocity/ frequency Young’s modulus (Y) strain/stress Units W/m2 dimensionless Ω
W cm V/K dimensionless N/m2 Kelvin (K) s W/(K m) K‐1 m/s m N/m2 Some symbols have to be determined by context: σ is used for both conductivity and stress, and Q is used for charge and Seebeck coefficient. This table is based on Appendix B of Iskander2. 2M. F. Iskander, Electromagnetic Fields and Waves, Waveland Press, 1992, pp. 720‐723.