Air at 1600 k, 30 bar enters a turbine operating at steady state and expands adiabatically to the exit, where the temperature is 830 k. if the isentropic turbine efficiency is 90%, determine (a) the pressure at the exit, in bar, and (b) the work developed, in kj per kg of air flowing. assume ideal gas behavior for the air and ignore kinetic and potential energy effects