The volt expression can be also given in the terms of joule and coulomb i.e in the units of energy and charge. One volt can be defined as the potential difference between the points which impart one unit of joule energy per one unit of coulomb charge which flows in the electric circuit. The mathematical expression of the definition is given as, V=J/C, where, V denotes the voltage, J for joule energy, C stands for coulomb charge.