Electromotive Force

Introduction

• Electromotive force, often abbreviated as E or emf, refers to the energy per unit electric charge supplied by an energy source, such as a battery or electric generator. Within these devices, energy undergoes conversion from one form to another as work is performed on the electric charge being transferred. This process results in one terminal of the device acquiring a positive charge while the other terminal becomes negatively charged. The electromotive force represents the work performed on a unit of electric charge and the energy gained per unit electric charge. 
• It characterizes the capability of any energy source to drive electric charge throughout a circuit. In the international metric system, electromotive force is denoted as E and measured in volts, which is equivalent to one joule per coulomb of electric charge. In the centimetre-gram-second system of electrostatic units, the unit of electromotive force is the statvolt, equivalent to one erg per electrostatic unit of charge. Despite its name, electromotive force does not refer to an actual force.