Question

A simple model of a photovoltaic solar cell is a current source, with the current proportional to the amount of sunlight falling on it. A more accurate model includes a diode (a nonlinear element we will see later). There is some leakage current that we can model with a parallel resistor, and there is a voltage drop in the interconnect that we can model with series resistances connecting to the load resistor. So a crude model of a complete system might be the circuit shown below.

Answer 1

use RL= Rp+Rs+Rs for load resistance and Thevenin equivalent resistance (both would have same answer)
and use P=I^2*RL