Consider the reversible adiabatic flow of stream through a nozzle. Steam enters the nozzle at 1 Mpa and 300°C with a velocity of 30 m/s. The pressure of the steam at the nozzle exit is 0.3 Mpa. Determine the exit velocity of the nozzle. If the actual nozzle exit velocity is measured to be 500 m/s, find the entropy change of the steam.