A well-insulated rigid tank contains 30 kg of saturated liquid-vapor mixture of H2O of quality 20% at 100 kPa. Electric heater inside the tank is turned on and kept until all liquid is vaporized. (4a). (5p) Please determine the work done by the electric heater during this process. (4b). (4p) Please determine the entropy change of the water during this process. (4c). (3p) Will Sgen be positive for this process