Quantity of Electricity or Charge

The electrostatic unit of charge, the quantity which when concentrated at a point and placed at unit distance from an equal and similarly concentrated quantity, is repelled with unit force. If the distance is one centimeter and force of repulsion one dyne and the surrounding medium a vacuum, we have the electrostatic unity of quantity. The electrostatic unit of quantity may be defined as that transferred by electrostatic unit current in unit time. The quantity transferred by one ampere in one second is the coulomb, the practical unit. The faraday is the electrical charge carried by one gram equivalent. The coulomb = 3 × 109 electrostatic units. Dimensions –

$$[e^{{1 \over 2}} m^{{1 \over 2}} l^{{3 \over 2}} t^{ - 1} ]; [\mu ^{ - {1 \over 2}} m^{{1 \over 2}} l^{{1 \over 2}}]$$

(CRC Handbook of Chemistry and Physics, Lide DR (ed) CRC Press, Boca Raton, FL, 2004 Version).