Agas turbine plant operates on the regenerative Brayton cycle with two stages of reheating and two stages of intercooling between the pressure limits of 100 and 1200 kPa. The working fluid is air. The air enters the first and second stages of the compressor at 300 K and 350 K, respectively, and the first and second stages of the turbine at 1400 K and 1300 K, respectively. Assuming both the compressor and the turbine have an isentropic efficiency of 80 percent and the regenerator has an efficiency of 75 percent and using the variable specific heats, determine (a) the back work ratio and the network output, (b) the thermal efficiency.