Steam at 5MPa, 500 Degrees C enters an insulted turbine operating at steady state with a mass flow rate of 7 kg/s and exits at 0.3 MPa. Kinetic and potential energy effects are negligible. Determine the maximum theoretical power that can be developed by the turbine, in kW, and the corressponding exit temperature. If the steam exits the turbine at 250 degree C and 0.5 MPa, determine the isentropic efficiency.