Consider a single crystal Si solar cell that has an ideality factor $()$ of $2.$ Assume that the equivalent parallel resistance $($Rp$)$ is negligible but not the series resistance $($Rs$).$ When the solar cell is under a light intensity of $800$ W m$-2,$ an electrical engineer measures an open circuit voltage $($Voc$)$ of $0\mathrm{.}590$ V and a short circuit current of $120$ mA$.$ He then connects an adjustable load RL across the solar cell and adjusts this load until the current is $85\mathrm{.}0$ mA$.$ The corresponding voltage across the solar cell is $0\mathrm{.}348$ V$.$ Assume that the room temperature is $27$C$.$ a What is the series resistance Rs of the solar cell?