A light bulb has resistance \(R_{\text {bulb }}=5.0 \Omega\) and should be operated at a potential difference of \(V_{\text {bulb }}=3.0 \mathrm{~V}\). If you must use this bulb in a circuit powered by a battery of \(\mathrm{emf} \mathscr{E}=9.0 \mathrm{~V}\), how much resistance must you add in series to the circuit in order to have a \(3.0-\mathrm{V}\) potential difference across the bulb?