Quantity of charge is proportional to to potential; that is, Q = CE, where Q is the quantity of charge in coulombs, E is the potential in volts, and C is a constant called the capacitance of the charged object. The unit of capacitance is the farad. Capacitance increases with the size of the object, and also increases if the charge is distributed between two conductors by induction, if the conductors are insulated from each other. (This is because for the same total quantity of electricity the potential, E, is lowered by the presence of the nearby induced charge of opposite polarity.)