Final answer:
The work done by the voltage source when the capacitor reaches steady-state is expressed as \( \frac{1}{2} C E^{2} \), where E is the voltage, and C is the capacitance.
Step-by-step explanation:
The work W done by the voltage source when the capacitor reaches the steady-state can be found by considering the energy stored in the capacitor. This is equal to the potential energy Uc given by the formula Uc = \( \frac{1}{2} C E^{2} \), where E is the electric potential (voltage), R is the resistance, and C is the capacitance. In the steady state, the work done by the voltage source to transfer charge until the capacitor is at potential E is equal to the energy stored in the capacitor. Thus, the work done W is \( \frac{1}{2} C E^{2} \).