Starting from the Norton equivalent circuit with a resistive load $R_{l}$, attached, find an expression for the power delivered to the load in terms of $I_{n}, R_{l},$ and $R_{L}$. Assuming that $I_{n}$ and $R_{f}$ are fixed values and that $R_{L}$ is variable, show that maximum power is delivered for $R_{L}=R_{t}$. Find an expression for maximum power delivered to the load in terms of $I_{n}$ and $R_{t}$