EMF, terminal p.d. and real cells
EMF, terminal p.d. and real cells

EMF is the energy supplied per unit charge by a source, so ε=WQ\varepsilon = \frac{W}{Q}ε=QW. It is measured in volts because 1 V=1 J/C1 \, \text{V} = 1 \, \text{J/C}1V=1J/C, but it is not a force.