A battery does work in moving charge around a circuit i.e. sustaining a current through the circuit. To illustrate this point, consider a resistor with a voltage V across it and a current I flowing through it. Part A Focus on a single charge, q, passing through the resistor. Find the work W done on the charge by the electric field in the resistor. Express the work W done on the charge in terms of q, V, and/or I.