a$)$ Classify the power plant into their various configuration.$($b$)$ Steam enters a convergent$-$divergent nozzle with a negligible velocity and P mass flow rate of $2\mathrm{.}5$ kg$/$s and it exits at a pressure of $300$ kPa. The flow is isentropic between the nozzle entrance and the throat. The nozzle efficiency is $93\%.$ Determine the $($a$)$ the throat and exit aeras. $($b$)$ the Mach number at the throat and the nozzle exit.