Question

The pressure ratio of a gas power plant cycle corresponding to maximum work output for the given temperature limits of T_min and T_max will be                                                                                                                           

      (a)  $\left ( \frac{T_{max}}{T_{min}} \right )^{\frac{\gamma }{2\left ( \gamma -1 \right )}}$                                                  (b) $\left ( \frac{T_{min}}{T_{max}} \right )^{\frac{\gamma }{2\left ( \gamma -1 \right )}}$

      (c)  $\left ( \frac{T_{max}}{T_{min}} \right )^{\frac{\gamma -1}{\gamma }}$                                                     (d) $\left ( \frac{T_{max}}{T_{min}} \right )^{\frac{\gamma -1}{\gamma }}$