P_2=\frac{V^2}{R}\ \Rightarrow\ R=\frac{V^2}{P_2}=20~\Omega \qquad\text{(in modo analogo)} \qquad Q_2=\frac{V^2}{X_L}\ \Rightarrow\ X_L=\frac{V^2}{Q_2}=50~\Omega

 \text{essendo } X_L=2\pi f,L \ \Rightarrow L=\frac{X_L}{2\pi f} =\frac{50}{2\pi\cdot100} =0.0795~\text{H}=79.5~\text{mH}

 \text{Quando i due elementi sono in serie:}\qquad P_1=R I^2 \ \Rightarrow\ I=\sqrt{\frac{P_1}{R}} =\sqrt{\frac{320}{20}} =4~\text{A}

 \text{Con questa corrente:}\quad V_L=X_L I=50\cdot4=200~\text{V}, \qquad V_R=RI=20\cdot4=80~\text{V}

 V=\sqrt{V_R^2+V_L^2} =\sqrt{200^2+80^2} =215.4~\text{V}